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Review of low cost synthesis of perovskite solar cells
| By Michigan Tech's Open Sustainability Technology Lab.
Wanted: Students to make a distributed future with solar-powered open-source 3-D printing.
- 1 Purpose
- 2 Current Design
- 3 p-type material layer(NiO)
- 3.1 p-type Mesoscopic Nickel Oxide/Organometallic Perovskite Heterojunction Solar Cells
- 3.2 Properties of Plasmon-Induced Photoelectric Conversion on a TiO2/NiO p–n Junction with Au Nanoparticles 
- 3.3 Solution deposited NiO thin-films as hole transport layers in organic photovoltaics
- 3.4 Solution-Processed Nickel Oxide Hole Transport Layers in HighEffi ciency Polymer Photovoltaic Cells 
- 3.5 Ultrafast Dynamics of Hole Injection and Recombination in Organometal Halide Perovskite Using Nickel Oxide as p-Type Contact Electrode
- 3.6 Effects of Cu doping on nickel oxide thin film prepared by sol–gel solution process 
- 3.7 Simulation of perovskite solar cells with inorganic hole transporting materials 
- 3.8 Introducing Cu2O Thin Films as a Hole-Transport Layer in Efficient Planar Perovskite Solar Cell Structures 
- 3.9 High-Performance and Environmentally Stable Planar Heterojunction Perovskite Solar Cells Based on a Solution-Processed Copper-Doped Nickel Oxide Hole-Transporting Layer 
- 3.10 Sol–gel deposited nickel oxide films for electrochromic applications
- 3.11 Structural and Electrical Functionality of NiO Interfacial Films in Bulk Heterojunction Organic Solar Cells
- 3.12 p-Type semiconducting nickel oxide as an efficiency-enhancing anode interfacial layer in polymer bulk-heterojunction solar cells
- 3.13 Transparent conducting p-type NiO thin films prepared by magnetron sputtering
- 4 TiO2/Graphene or ZnO (n-type Layer)
- 4.1 Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells
- 4.2 Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells Supporting Information
- 4.3 Measurement of Multicomponent Solubility Parameters for Graphene Facilitates Solvent Discovery
- 4.4 High-yield production of graphene by liquid-phase exfoliation of graphite
- 4.5 High-yield production of graphene by liquid-phase exfoliation of graphite Supporting Information
- 4.6 Solution processable titanium dioxide precursor and nanoparticulated ink: application in Dye Sensitized Solar Cells
- 4.7 Solution processable titanium dioxide precursor and nanoparticulated ink: Application in Dye Sensitized Solar Cells
- 4.8 Preparation of TiO2 Sol Using TiCl4 as a Precursor
- 4.9 Hydrolysis preparation of the compact TiO2 layer using metastable TiCl4 isopropanol/water solution for inorganic–organic hybrid heterojunction perovskite solar cells
- 4.10 Approach
- 4.11 Speciation in diethanolamine-moderated TiO2 precursor sols and their use in film formation
- 4.12 Photo-induced monomer/dimer kinetics in methylene blue degradation over doped and phase controlled nano-TiO2 films
- 4.13 Transparent thin films of Cu–TiO2 with visible light photocatalytic activity
- 4.14 Effects of solvent on properties of sol—gel-derived TiO2 coating films
- 4.15 Origin of the Thermal Instability in CH3NH3PbI3 Thin Films Deposited on ZnO
- 4.16 Electroluminescence from light-emitting polymer/ZnO nanoparticle heterojunctions at sub-bandgap voltages
- 5 Perovskite Layer - active layer
- 6 3D printing papers
- 6.1 Toward Large Scale Roll-to-Roll Production of Fully Printed Perovskite Solar Cells 
- 6.2 Fully spray-coated ITO-free organic solar cells for low-cost power generation 
- 6.3 Optically monitored spray coating system for controlled deposition of photoactive layer in organic solar cells
- 6.4 Organic photovoltaic modules fabricated by an industrial gravure printing proofer
- 6.5 An inter-laboratory stability study of roll-to-roll coated flexible polymer solar modules
- 6.6 3D Printer Based Slot-Die Coater as a Lab-to-Fab Translation Tool for Solution-Processed Solar Cells 
- 6.7 A stability study of roll-to-roll processed organic photovoltaic modules containing a polymeric electron-selective layer 
- 6.8 Reverse gravure coating for roll-to-roll production of organic photovoltaics 
- 6.9 Back-Contacted Hybrid Organic-Inorganic Perovskite Solar Cells 
- 6.10 Photonic Sintering of Copper through the Controlled Reduction of Printed CuO Nanocrystals 
- 6.11 Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells 
- 6.12 Polymer solar cell modules prepared using roll-to-roll methods: Knife-over-edge coating, slot-die coating and screen printing
- 7 Papers Found
- 7.1 Review Articles Group 1
- 7.1.1 Perovskite solar cells: an emerging photovoltaic technology
- 7.1.2 progress and future perspectives for organic/inorganic perovskite solar cells
- 7.1.3 The light and shade of perovskite solar cells
- 7.1.4 Organolead halide perovskite: A rising player in high-efficiency solar cells
- 7.1.5 Trend of Perovskite Solar Cells: Dig Deeper to Build Higher
- 7.1.6 A brief history of perovskite materials for photovoltaic applications
- 7.2 Focused Papers-Solar Cell Group 1
- 7.2.1 Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells
- 7.2.2 High efficiency CH3NH3PbI(3−x)Clx perovskite solar cells with poly(3-hexylthiophene) hole transport layer
- 7.2.3 Influence of compact TiO2 layer on the photovoltaic characteristics of the organometal halide perovskite-based solar cells
- 7.2.4 Gas-assisted preparation of lead iodide perovskite films consisting of a monolayer of single crystalline grains for high efficiency planar solar cells
- 7.2.5 Charge Transport and Recombination in Perovskite (CH3NH3)PbI3 Sensitized TiO2 Solar Cells
- 7.2.6 Optical bleaching of perovskite (CH3NH3)PbI3 through room-temperature phase transformation induced by ammonia
- 7.2.7 Solid-State Mesostructured Perovskite CH3NH3PbI3 Solar Cells: Charge Transport, Recombination, and Diffusion Length
- 7.2.8 Low-Temperature and Solution-Processed Amorphous WOX as Electron-Selective Layer for Perovskite Solar Cells
- 7.2.9 Crystal Morphologies of Organolead Trihalide in Mesoscopic/Planar Perovskite Solar Cells
- 7.2.10 Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode
- 7.3 Review Articles Group 2
- 7.4 Focused Papers-Solar Cell Group 2
- 7.4.1 Efficient organic–inorganic hybrid perovskite solar cells processed in air 
- 7.4.2 Study on the stability of CH3NH3PbI3 films and the effect of post-modification by aluminum oxide in all-solid-state hybrid solar cells
- 7.4.3 Sub-150C processed meso-superstructured perovskite solar cells with enhanced efficiency
- 7.4.4 Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates
- 7.4.5 Carbon Nanotube/Polymer Composites as a Highly Stable Hole Collection Layer in Perovskite Solar Cells
- 7.4.6 Efficient planar heterojunction perovskite solar cells by vapour deposition
- 7.4.7 Environmentally responsible fabrication of efficient perovskite solar cells from recycled car batteries
- 7.4.8 Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells
- 7.4.9 New Physical Deposition Approach for Low Cost Inorganic Hole Transport Layer in Normal Architecture of Durable Perovskite Solar Cells
- 7.4.10 Metal/Metal-Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO3
- 7.4.11 Small Photocarrier Effective Masses Featuring Ambipolar Transport in Methylammonium Lead Iodide Perovskite: A Density Functional Analysis
- 7.4.12 Comparison of transparent conductive indium tin oxide, titanium-doped indium oxide, and fluorine-doped tin oxide films for dye-sensitized solar cell application
- 7.4.13 Screening procedure for structurally and electronically matched contact layers for high-performance solar cells: hybrid perovskites
- 7.4.14 Research improves efficiency from larger perovskite solar cells
- 7.5 Focused Papers-3D Printing
- 7.1 Review Articles Group 1
This literature review is meant to provide an understanding of the usefulness and properties of perovskites as a material for 3D printing solar cells.
This lit review needs to be reorganized into categories related to each layer and the materials each layer could be printed with.Furthermore, a section on printing powdered materials in a solvent should be added.
- Metal contact - Aluminum Metal
- Hole Transporting Material - NiO np
- Sensitier - CH3NH3PbIx-3BrxClx
- Mesoscopic Layer - Al2O3 np
Al2O3 gamma np - Reasoning for gamma over alpha: highly porous, potentially catalytic features - need paper citation
- Electron Transporting Material - TiO2 & graphene flakes
- Transparent Conducting Oxide - Florine doped Tin-Oxide
Reusing lead "Recycling lead acid batteries into perovskite solar cells."
Used for syringe design Open-source syringe pump
3D printer used and modified []
Used for Raspberry Pi set up on prusa for franklin How to install FLIR Lepton Thermal Camera and applications on Raspberry Pi
- Upload images and then upload to github.
- Surface Roughness
p-type material layer(NiO)
Kuo-Chin Wang J-YJ. "p-type Mesoscopic Nickel Oxide/Organometallic Perovskite Heterojunction Solar Cells" Scientific reports. 2014;4:4756.
- This paper was the initial reasoning for using NiO as a p-type metal oxide HTM material
Fabrication of NiOx solution The precursor for NiOx film coating was prepared with 0.5 M nickel formate dihydrate (Alfa Aesar) in ethylene glycol solution containing 1 M ethylenediamine (Aldrich) and filtered with 0.45 μm nylon filters41.
Fabrication of NiOnc paste The mesoporous NiO solution used for spin coating was prepared by diluting slurry NiO with anhydrous ethanol in a ratio of 1:7. Slurry NiO was prepared by mixing 3 g of NiO nanopowder (Inframat) in 80 ml ethanol and subsequently adding with 15 g of 10 wt% ethyl cellulose (in EtOH) and 10 g of terpineol. The solution was stirred and dispersed with ultrasonic horn and concentrated with rotary evaporator for ethanol removal until 23 mbar
- Goal is to encompass the perovskite inside metal oxides to massively increase stability of the cell.
Properties of Plasmon-Induced Photoelectric Conversion on a TiO2/NiO p–n Junction with Au Nanoparticles 
Free source: 
Abstract (Just accepted article)
We have successfully fabricated all-solid-state plasmonic photoelectric conversion devices composed of titanium dioxide (TiO2)/nickel oxide (NiO) p-n junctions with gold nanoparticles (Au-NPs) as prototype devices for a plasmonic solar cell. The characteristics of the crystal structures and the photoelectric properties of the all-solid-state devices were demonstrated. We observed that the crystalline structure of the NiO thin film and the interfacial structure of TiO2/Au-NPs/NiO changed significantly during an annealing treatment. Furthermore, the photoelectric conversion devices exhibited plasmon-induced photocurrent generation in the visible-wavelength region. The photocurrent may result from plasmon-induced charge separation. The photoelectric conversion properties via plasmon-induced charge separation were strongly correlated with the morphology of the TiO2/Au-NPs/NiO interface. The long-term stability of the plasmonic photoelectric conversion device was found to be very high because a stable photocurrent was observed even after irradiation for 3 days.
- Good info on the use of NiO and TiO2
Organic solar cells require suitable anode surface modifiers in order to selectively collect positive charge carriers and improve device performance. We employ a nickel metal organic ink precursor to fabricate NiO hole transport layers on indium tin oxide anodes. This solution deposited NiO annealed at 250 C and plasma treated, achieves similar OPV device results reported with NiO films from PLD as well as PEDOT:PSS. We demonstrate a tunable work function by post-processing the NiO with an O2-plasma surface treatment of varied power and time. We find that plasma treatment is necessary for optimal device performance. Optimal devices utilizing a solution deposited NiO hole transport layer show lower series resistance and increased fill factor when compared to solar cells with PEDOT:PSS.
- Good for scientific reasoning to not use organics for HTM
- Solid background on NiO
- Utilizies a NiO ink patented by the NREL, however it requires plasma treatment
Solution-Processed Nickel Oxide Hole Transport Layers in HighEffi ciency Polymer Photovoltaic Cells 
The detailed characterization of solution-derived nickel (II) oxide (NiO) holetransporting layer (HTL) fi lms and their application in high effi ciency organic photovoltaic (OPV) cells is reported. The NiO precursor solution is examined in situ to determine the chemical species present. Coordination complexes of monoethanolamine (MEA) with Ni in ethanol thermally decompose to form non-stoichiometric NiO. Specifi cally, the [Ni(MEA) 2(OAc)] + ion is found to be the most prevalent species in the precursor solution. The defect-induced Ni 3 + ion, which is present in non-stoichiometric NiO and signifi es the p-type conduction of NiO, as well as the dipolar nickel oxyhydroxide (NiOOH) species are confi rmed using X-ray photoelectron spectroscopy. Bulk heterojunction (BHJ) solar cells with a polymer/fullerene photoactive layer blend composed of poly-dithienogermole-thienopyrrolodione (pDTG-TPD) and [6,6]-phenyl-C71-butyric acid methyl ester (PC 71 BM) are fabricated using these solution-processed NiO fi lms. The resulting devices show an average power conversion effi ciency (PCE) of 7.8%, which is a 15% improvement over devices utilizing a poly(3,4 ethylenedioxythiophene):poly(styrenesulf onate)(PEDOT:PSS) HTL. The enhancement is due to the optical resonance in the solar cell and the hydrophobicity of NiO, which promotes a more homogeneous donor/acceptor morphology in the active layer at the NiO/BHJ interface. Finally, devices incorporating NiO as a HTL are more stable in air than devices using PEDOT:PSS.
- Signifies that an in order to deposit an ultra-thin layer of NiO, a solution stabilizer (amine) is needed, in this case monoethanolamine.
- 5nm thickness was achieved allowing for 95% light transmittance.
NiO Precursor Solution : Nickel acetate tetrahydrate(Ni(CH 3COO) 2· 4H 2 O) (Acros Organics) was dissolved in ethanol with monoethanolamine (NH 2CH 2CH 2 OH) (Sigma-Aldrich) (0.1 mol L − 1). The mole ratio of Ni 2 + : MEA was maintained at 1:1 in solution. Dissolution took place while stirring in a sealed glass vial under air at 70 ° C for 4 h. The solution appeared homogeneous and deep green after approximately 40 min.
Ultrafast Dynamics of Hole Injection and Recombination in Organometal Halide Perovskite Using Nickel Oxide as p-Type Contact Electrode
There is a mounting effort to use nickel oxide (NiO) as p-type selective electrode for organometal halide perovskite-based solar cells. Recently, an overall power conversion efficiency using this hole acceptor has reached 18%. However, ultrafast spectroscopic investigations on the mechanism of charge injection as well as recombination dynamics have yet to be studied and understood. Using time-resolved terahertz spectroscopy, we show that hole transfer is complete on the subpicosecond time scale, driven by the favorable band alignment between the valence bands of perovskite and NiO nanoparticles (NiO(np)). Recombination time between holes injected into NiO(np) and mobile electrons in the perovskite material is shown to be hundreds of picoseconds to a few nanoseconds. Because of the low conductivity of NiO(np), holes are pinned at the interface, and it is electrons that determine the recombination rate. This recombination competes with charge collection and therefore must be minimized. Doping NiO to promote higher mobility of holes is desirable in order to prevent back recombination.
- Organometal lead halide perovskite based materials are attractive research topics because of long charge diffusion lengths, broad absorption ranges from visible to infrared, high absorption coefficints, low exciton binding energy, and a direct optical bandgap around 1.5eV.
- NiO shows to have a hole injection similar in time scale to that of electron injection into TiO2.
- Recombination occurs sometime between several hundred picoseconds to a few nanoseconds due to the pinning holes at the interface between NiO and perovskite material.
- Emphasises a need of doping NiO in order into increase the lifetime of electrons and holes.
- This paper has solid photoconductivity kinetics data.
We prepared nickel oxide (NiO) thin films with p-type Cu dopants (5 at%) using a sol–gel solution process and investigated their structural, optical, and electrical characteristics by X-ray diffraction (XRD), atomic force microscopy (AFM), opticaltransmittance and current–voltage (I–V) characteristics. The crystallinity of the NiO films improved with the addition of Cu dopants, and the grain size increased from 38 nm (nondoped) to 50 nm (Cu-doped). The transmission of the Cu-doped NiO film decreased slightly in the visible wavelength region, and the absorption edge of the film red-shifted with the addition of the Cu dopant. Therefore, the width of the optical band gap of the Cu-doped NiO film decreased as compared to that of the non-doped NiO film. The resistivity of the Cu-doped NiO film was 23 m, which was significantly less than that of the non-doped NiO film (320 m). Thus, the case of Cu dopants on NiO films could be a plausible method for controlling the properties of the films.
- Useful if processing to dope NiO with Cu.
- Chemicals used:
- Nickel acetate tetrahydrate(Ni(COOCH3)2·4H2O, 0.3 M)
- Copper acetate monohydrate (Cu(CH3COO)2·H2O, 5 at%)
- Both dissolved in: 2-methoxyethanol (2ME), and hydrochloric acid (HCl)
- The solution was stirred at 60 ◦C for 1 h and then aged for 24 h at room temperature. Annealed at 550C for 1 hour
Device modeling organolead halide perovskite solar cells with planar architecture based on inorganic hole transporting materials (HTMs) were performed. A thorough understanding of the role of the inorganic HTMs and the effect of band offset between HTM/absorber layers is indispensable for further improvement in power conversion efficiency (peE). Here, we investigated the effect of band offset between inorganic HTM/absorber layers. The solar cell simulation program adopted in this work is named wxAMPS, an updated version of the AMPS tool (Analysis of Microelectronic and Photonic Structure).
- Useful for direction of copper doped NIO layer or Cu2O layer
- Regard for future work on NiO
Introducing Cu2O Thin Films as a Hole-Transport Layer in Efficient Planar Perovskite Solar Cell Structures 
In this work, we introduce Cu2O thin films as a hole-transport layer in planar perovskite solar cells. Here, a Cu2O layer was formed through successive ionic layer adsorption and reaction (SILAR) method. With methylammonium lead triiodide (MAPbI3) we form a direct structure (p− i−n), where the perovskite layer is sandwiched between a layer of p-type Cu2O and another layer of n-type PCBM (phenylC61-butyric acid methyl ester), which acted as hole- and electron-transport materials, respectively. We locate band edges of the materials with respect to their Fermi energy by recording scanning tunneling spectroscopy that has correspondence to their density of states (DOS). We observe that the energy levels of the materials form type II band alignments at each of the two interfaces (p−i and i−n) for charge separation and uninterrupted carrier transport upon illumination. Such a band alignment enabled charge transfer from MAPbI3 as evidenced from quenching of its photoluminescence emission when the perovskite was in contact with either the hole- or the electron-transport layer. With the direct p−i−n structure having appropriate energy levels for carrier separation, the planar perovskite solar cell (Cu2O/MAPbI3/PCBM) yielded an energy conversion efficiency (η) of 8.23% under 1 sun illumination.
- NiO alternative
High-Performance and Environmentally Stable Planar Heterojunction Perovskite Solar Cells Based on a Solution-Processed Copper-Doped Nickel Oxide Hole-Transporting Layer 
- For use with Cu in NiO
The electrochromic (EC) behavior, the microstructure, and the morphology of sol–gel deposited nickel oxide (NiOx) coatings were investigated. The films were produced by spin and dip-coating techniques on indium tin oxide (ITO)/glass and Corning glass (2947) substrates. The coating solutions were prepared by reacting nickel(II) 2-ethylhexanoate as the precursor, and isopropanol as the solvent. NiOx was heat treated at 350 °C for 1 h. The surface morphology, crystal structure, and EC characteristics of the coatings were investigated by scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), atomic force spectroscopy (AFM), X-ray diffractometry (XRD), and cyclic voltammetry (CV). SEM and AFM images revealed that the surface morphology and surface characteristics of the spin- and dip-coated films on both types of substrate were different. XRD spectra revealed that both films were amorphous, either on ITO or Corning glass substrates. CV showed a reversible electrochemical insertion or extraction of the K+ ions, cycled in 1 M KOH electrolyte, in both type of film. The crystal structure of the cycled films was found to be XRD amorphous. Spectroelectrochemistry demonstrated that dip-coated films were more stable up to 1000 coloration–bleaching cycles, whereas spin-coated films gradually degraded after 500 cycles.
- useful for comparing dip technique to the spin coating technique. Good images.
Structural and Electrical Functionality of NiO Interfacial Films in Bulk Heterojunction Organic Solar Cells
The functionality of NiO interfacial layers in enhancing bulk heterojunction (BHJ) organic photovoltaic (OPV) cell performance is investigated by integrated characterization of the electrical properties, microstructure, electronic structure, and optical properties of thin NiO films grown on glass/ITO electrodes. These NiO layers are found to be advantageous in BHJ OPV applications due to favorable energy band levels, interface passivation, p-type character, crystallinity, smooth surfaces, and optical transparency. The NiO overlayers are fabricated via pulsed-laser deposition and found to have a work function of ∼5.3 eV. They are investigated by both topographic and conductive atomic force microscopy and shown to passivate interfacial charge traps. The films also have an average optical transparency of >80% in the visible range, crucial for efficient OPV function, and have a near-stoichiometric Ni:O surface composition. By grazing-incidence X-ray diffraction, the NiO thin films are shown to grow preferentially in the (111) direction and to have the fcc NaCl crystal structure. Diodes of p�n structure and first-principles electronic structure calculations indicate that the NiO interlayer is preferentially conductive to holes, with a lower hole charge carrier effective mass versus that of electrons. Finally, the implications of these attributes in advancing efficiencies for state-of-the-art OPV systems—in particular, improving the open circuit voltage (VOC)—are
- Critical Paper
p-Type semiconducting nickel oxide as an efficiency-enhancing anode interfacial layer in polymer bulk-heterojunction solar cells
To minimize interfacial power losses, thin (5–80 nm) layers of NiO, a p-type oxide semiconductor, are inserted between the active organic layer, poly(3-hexylthiophene) (P3HT) + [6,6]-phenyl-C61 butyric acid methyl ester (PCBM), and the ITO (tin-doped indium oxide) anode of bulk-heterojunction ITO/P3HT:PCBM/LiF/Al solar cells. The interfacial NiO layer is deposited by pulsed laser deposition directly onto cleaned ITO, and the active layer is subsequently deposited by spin-coating. Insertion of the NiO layer affords cell power conversion efficiencies as high as 5.2% and enhances the fill factor to 69% and the open-circuit voltage (V oc) to 638 mV versus an ITO/P3HT:PCBM/LiF/Al control device. The value of such hole-transporting/electron-blocking interfacial layers is clearly demonstrated and should be applicable to other organic photovoltaics. discussed.
- important for demonstrating NiO effect on a cell.
- 5-10 nm thickness of layer is shown to be ideal with significant PCE drop if the layer thickness is increased to even just 30nm.
Transparent and conductive thin films consisting of p-type nickel oxide (NiO) semiconductors were prepared by r.f. magnetron sputtering. A resistivity of 1.4 × 10−1 ohms cm and a hole concentration of 1.3 × 1019 cm−3 were obtained for non-intentionally doped NiO films prepared at a substrate temperature of 200°C in a pure oxygen sputtering gas. An average transmittance of about 40% in the visible range was obtained for a 110 nm thick NiO film. A semitransparent thin film pin diode consisting of p-NiO/i-NiO/i-ZnO/n-ZnO layer having a voltage-current rectification characteristic and an average transmittance above 20% in the visible range was fabricated on a glass substrate.
TiO2/Graphene or ZnO (n-type Layer)
Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells
Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells Supporting Information
Measurement of Multicomponent Solubility Parameters for Graphene Facilitates Solvent Discovery
High-yield production of graphene by liquid-phase exfoliation of graphite Supporting Information
Solution processable titanium dioxide precursor and nanoparticulated ink: application in Dye Sensitized Solar Cells
Solution processable titanium dioxide precursor and nanoparticulated ink: Application in Dye Sensitized Solar Cells
Hydrolysis preparation of the compact TiO2 layer using metastable TiCl4 isopropanol/water solution for inorganic–organic hybrid heterojunction perovskite solar cells
Photo-induced monomer/dimer kinetics in methylene blue degradation over doped and phase controlled nano-TiO2 films
9 mL of titanium(IV) isopropoxide was added to 120 mL isopropanol. Subsequently 0.3 mL 2 M HCl was added drop by drop.
Electroluminescence from light-emitting polymer/ZnO nanoparticle heterojunctions at sub-bandgap voltages
Perovskite Layer - active layer
Ultrasmooth organic–inorganic perovskite thin-film formation and crystallization for efficient planar heterojunction solar cells
To date, there have been a plethora of reports on different means to fabricate organic–inorganic metal halide perovskite thin films; however, the inorganic starting materials have been limited to halide-based anions. Here we study the role of the anions in the perovskite solution and their influence upon perovskite crystal growth, film formation and device performance. We find that by using a non-halide lead source (lead acetate) instead of lead chloride or iodide, the perovskite crystal growth is much faster, which allows us to obtain ultrasmooth and almost pinhole-free perovskite films by a simple one-step solution coating with only a few minutes annealing. This synthesis leads to improved device performance in planar heterojunction architectures and answers a critical question as to the role of the anion and excess organic component during crystallization. Our work paves the way to tune the crystal growth kinetics by simple chemistry.
- Critical paper
- Tio2 process to be repeated if low temp graphene layer process does not work: "A hole-blocking layer of compact TiO2 was deposited by spin-coating a mildly acidic solution of titanium isopropoxide in ethanol, and annealed at 500 °C for 30 min. Spin-coating was carried out at 2,000 r.p.m. for 60
3D printing papers
Solar cell technology has been developed to harvest solar energy more efficiently as well as more economically. Third-generation solar cells, including chemical-compound solar cells (CIGS, CdTe), dye-sensitized solar cells (DSSCs), and organic photovoltaics (OPVs), have been intensively studied during the past decade for their potential low production costs. [ 1–6 ] Recently, organic-inorganic hybrid perovskite solar cells have emerged as the most promising of the third-generation solar cells with an increased record of efficiency that has risen to 19.3% [ 7 ] from 3.8% [ 8 ] in last 4 years. In addition to record efficiencies published in the literature, a certified record efficiency of over 20% [ 9 ] has been reported very recently, albeit with no details disclosed. This record efficiency is already comparable to that of silicon solar cells. [ 9 ] The next challenge in the field will be translating the lab-scale process to a large-scale production process, which will preferably include a cost-competitive roll-to-roll printing process.
- This is a very useful paper as it proves a methodology to create a soloar cell of PCE: 11.94%.
- ITO/ZnO/MAPbI3/P3HT/Ag is the architecture used.
- ITO was sonicated
- ZnO np were coated and annealed at 120C for 10 minutes
- PbI2 in N , N -dimethylformamide was stirred for 1h at 70C then coated and dried with N2 and transferred to an enclosed space.
- CH3NH3I was synthesized and coated onto the PbI2 layer with bed temp at 70C.
- P3HT was immediately deposited to prevent moisture from damaging the perovskite layer.
- Ag was deposited via ion-deposition
- Entire process was carried out at ambient temp and humidity.
- Created a 10mm^2 section for testing
- This process can easily be adapted from a slot-die to a syringe pump process.
- ZnO is an alternative to TiO2, may be beneficial for reasons such as deposition temperature/ precursor solution(verify).
- The intrinsic layer is a good layer in this set up, they went through a lot of testing for printing optimization of the PbI2, worthy of modeling.
- I would use the NiO instead of P3Ht due to chemicals used, and it appears NiO should be easy to deposit.
- Overall, based on this design the process could take a few hours to do in a lab, but could easily be scaled up for industry.
We report on cost-effective ITO-free organic solar cells (OSCs) fabricated by a spray deposition method. All solution-processable layers of solar cells—a highly conductive poly(3,4-ethylenedioxythiophene):-poly(styrenesulfonate) (PEDOT:PSS) layer and a photoactive layer based on poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM)—were spray-coated. PEDOT:PSS anode films with various thicknesses were prepared by controlling the spray deposition time. The transmittance and sheet resistance of PEDOT:PSS anodes were varied from 89.0% to 67.4% and from 358 to 63.3 O/squares, respectively, corresponding to an increase in film thickness. The best device exhibited a high power conversion efficiency of 2.17% under 100 mW cm2 illumination with air mass (AM) 1. 5 global (G) condition. More importantly, the efficiency of the fully spray-coated OSC with the PEDOT:PSS anode was comparable to that of conventional ITO-based devices, demonstrating the feasibility of fabricating all-spray-deposited OSCs without a conventional spin-coating method and the possibility of replacing the costly vacuum-deposited indium tin oxide (ITO) with highly conductive polymer films fabricated by inexpensive spray deposition techniques.
Optically monitored spray coating system for controlled deposition of photoactive layer in organic solar cells
A Spray deposition process equipped with an in-situ optical thickness monitoring system has been developed to fabricate the photo active layer of solar cells. Film thickness is monitored by a photodiode –LED couple after each deposition cycle. It is found thickness of spray deposited photo active film linearly increase with deposition cycle over a wide range of deposition conditions. After instrument calibration, optimization of the active layer thickness can be accomplished by simply setting the desired absorbance of the film. The simple process is used for rapid optimization of devices based on poly(3-hexylthiophene-2,5-diyl) (P3HT) and Phenyl-C61-butyric acid methyl ester as well as P3HT and indene-C60 bis-adduct combination to achieve up to 4.21 % power conversion efficiency.
Large-area, flexible organic photovoltaic (OPV) modules are fabricated successfully by gravure printing in air, using an industrial-scale printing proofer of similar performance to commercial roll-to-roll printing processes. Both the hole transport layer, poly-3,4-ethylenedioxy-thiophene:poly(styrene sulfonic-acid) (PEDOT:PSS), and the active layer, poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM), are successively printed on indium tin oxide (ITO) coated polyethylene terephthalate (ITO/PET) substrates with evaporated aluminum (Al) top electrodes. The 45 cm2 modules, composed of 5 cells connected in series, show power conversion efficiency (PCE) of over 1.0%, in which the short-circuit current (Jsc) and open-circuit voltage (Voc) are as high as 7.14 mA/cm2 and 2.74 V (0.55 V per cell), respectively. The PCEs could be potentially improved by the further optimization of the layer interface, layer morphology and flexible substrate properties. The results suggest that gravure printing may be a suitable technique for fast commercial processing of large-area, flexible OPVs with high output.
A large number of flexible polymer solar modules comprising 16 serially connected individual cells was prepared at the experimental workshop at Risø DTU. The photoactive layer was prepared from several varieties of P3HT (Merck, Plextronics, BASF and Risø DTU) and two varieties of ZnO (nanoparticulate, thin film) were employed as electron transport layers. The devices were all tested at Risø DTU and the functional devices were subjected to an inter-laboratory study involving the performance and the stability of modules over time in the dark, under light soaking and outdoor conditions. 24 laboratories from 10 countries and across four different continents were involved in the studies. The reported results allowed for analysis of the variability between different groups in performing lifetime studies as well as performing a comparison of different testing procedures. These studies constitute the first steps toward establishing standard procedures for an OPV lifetime characterization.
3D Printer Based Slot-Die Coater as a Lab-to-Fab Translation Tool for Solution-Processed Solar Cells 
Solution-processed solar cells continue to show great promise as a disruptive energy generation technology due to their inherently low manufacturing costs and increasing effi ciencies. [ 1–3 ] In this communication, we report the use of a 3D printer platform as a fabrication tool for solution-processed solar cells. This scalable, easily transferable coating process was used to make devices of different sizes and structures toward the aim of advancing the large-scale development of solution-processed solar cells. Organic bulk heterojunction (BHJ) and perovskitebased devices are both examples of solution-processed solar cells that can be made at low temperature, from solution and onto fl exible substrates. Recent advances in material and device structure development have seen lab-scale device power conversion effi ciencies (PCEs) approach those of more established solar technologies. For BHJ devices, the highest power conversion effi ciency reported in the open, peer-reviewed literature is over 9% [ 4 ] while a value of 11.1% has been reported for a device based on an undisclosed structure. [ 5 ] The earliest reports of organolead halide perovskite-based solar cells used a dye sensitized solar cell (DSSC) confi guration which requires a sintered TiO 2 particle layer. [6,7] The PCE of devices using mesoporousbased structures have been rapidly increasing. A record effi ciency of 19.3% has been reported very recently. [ 8 ] Perovskite-based devices without mesoporous TiO 2 structure have also been developed recently. It is reported that over 15% PCE can be achieved via a low temperature, solution-based process
A stability study of roll-to-roll processed organic photovoltaic modules containing a polymeric electron-selective layer 
The stability of roll-to-roll processed organic photovoltaic modules having an inverted structure and incorporating polyethylenimine–ethoxylate (PEIE) as the electron-selective layer was investigated. Large-area modules were fabricated on ITO-coated PET substrates using roll-to-roll coating and printing methods. Modules were encapsulated with commercially-available ultra-high gas/vapor barrier films by employing new encapsulation protocols developed during this work. The operational lifetime of modules on storage in an environmental chamber at ambient temperature and relative humidity of 35 °C and 50%, respectively, and under continuous simulated AM1.5G illumination was found to increase by more than three orders of magnitude upon encapsulation. The chemical stability of the PEIE films under these storage conditions was also studied. Fracture tests were conducted on modules exposed to the same storage conditions to investigate the effects on inter- and intra-layer adhesion and cohesion. An increase in adhesive strength was found for the exposed devices indicating an absence of any substantial mechanical degradation of the deposited layers for the exposure conditions used during this work. The results described here demonstrate the potential utility of commercially-available PEIE as a convenient and effective organic electron-selective layer for the fabrication of durable roll-to-roll processed organic solar cell devices.
Reverse gravure (RG) coating is reported here as an alternate film deposition method for potential large scale roll-to-roll production of organic photovoltaic devices (OPVs). The basic working principles of RG coating are shown and compared to the more well-known gravure printing. Gravure printing is similar to RG coating from a process point of view, but the films produced using each method are very different to each other. An optical thickness measurement system was developed and used to monitor film thickness variation of RG coated photo-active layers with various coating parameters in situ in the roll-to-roll process. Partially and fully printed OPV modules were fabricated using, primarily, the roll-to-roll RG coating process and devices showed 2.1% and 1.5% power conversion efficiencies, respectively.
A novel architecture for quasi-interdigitated electrodes (QIDEs) allows for the fabrication of back-contacted perovskite solar cells. The devices showed a stable power output of 3.2%. The design of the QIDEs avoids the defects that cause short-circuiting in conventional IDEs, while enhancing the collection area of the electrodes. Photoluminescence and photocurrent mapping is used to probe the charge generation and transport properties of the perovskite solar cells.
Photonic Sintering of Copper through the Controlled Reduction of Printed CuO Nanocrystals 
The ability to control chemical reactions using ultrafast light exposure has the potential to dramatically advance materials and their processing toward device integration. In this study, we show how intense pulsed light (IPL) can be used to trigger and modulate the chemical transformations of printed copper oxide features into metallic copper. By varying the energy of the IPL, CuO films deposited from nanocrystal inks can be reduced to metallic Cu via a Cu2O intermediate using single light flashes of 2 ms duration. Moreover, the morphological transformation from isolated Cu nanoparticles to fully sintered Cu films can also be controlled by selecting the appropriate light intensity. The control over such transformations enables for the fabrication of sintered Cu electrodes that show excellent electrical and mechanical properties, good environmental stability, and applications in a variety of flexible devices.
Differentially pumped spray deposition as a rapid screening tool for organic and perovskite solar cells 
We report a spray deposition technique as a screening tool for solution processed solar cells. A dual-feed spray nozzle is introduced to deposit donor and acceptor materials separately and to form blended films on substrates in situ. Using a differential pump system with a motorised spray nozzle, the effect of film thickness, solution flow rates and the blend ratio of donor and acceptor materials on device performance can be found in a single experiment. Using this method, polymer solar cells based on poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) are fabricated with numerous combinations of thicknesses and blend ratios. Results obtained from this technique show that the optimum ratio of materials is consistent with previously reported values confirming this technique is a very useful and effective screening method. This high throughput screening method is also used in a single-feed configuration. In the single-feed mode, methylammonium iodide solution is deposited on lead iodide films to create a photoactive layer of perovskite solar cells. Devices featuring a perovskite layer fabricated by this spray process demonstrated a power conversion efficiencies of up to 7.9%.
Polymer solar cell modules prepared using roll-to-roll methods: Knife-over-edge coating, slot-die coating and screen printing
Review Articles Group 1
- Article includes history of Perovskite technology
- The ABX3 structure is discussed. (X=O,C,N,halogen) X anion is most effective as a halogen. Emphasis on the B cation octahedral and A cation cubo-octahedral structure.
- Carrier diffusion lengths found to be greater than one micron for both electrons and holes.
- A architecture of FTO/bl-TiO2/MAPbI3/Au resulted in a PCE of 8%. Devoid of a mesopourous TiO2 layer and HTM. (MA = CH3NH3)
- A mixed halide perovskite (MAPbI3-xBrx) (x=0-3) appeared more stable in moisture. Br is suspected to stabilize the Ch3NH3+ cation in the lattice.
- A mixed halide perovskite (I,Br,Cl) would also allow the tuning of the band gap for greater light absorption.
- In general: iodides cause a smaller bandgap and longer wavelength light emission, while bromides cause a higher bandgap and shorter wavelength light emission.
- MAPb3 has a bandgap of 1.55eV, optimum is about 1.4eV
- The compact TiO2 layer is needed for collecting the generated electrons and blocking holes.
- Because the Al2O3 conduction band is higher than the absorber's LUMO, no electron injection from the perovskite takes place, indicating that the electron transport occurs within the perovskite itself.
- MAPbI3 has a high extinction coefficient, which ensures a good absorption of light at low mesoporous film thickness
- the crystallizing nature of perovskite upon deposition is important for both conductivity and charge generation since the crystallinity determines the distribution of energetic states.
- Used archetecture: Glass/FTO/TiO2-bl/Al2O3 scafold/MAPbI3/Spiro-OMeTAD/metal contact resulted in a PCE of 10.9%
- TiO2/CH3NH3PbI3/Au contact resulted in a PCE of 5.5%
- Abstract: The rise of metal halide perovskites as light harvesters has stunned the photovoltaic community. As the efficiency race continues, questions on the control of the performance of perovskite solar cells and on its characterization are being addressed.
- Abstract: This perspective presents a brief description of organolead halide perovskite-based solar cells, including the structures and fundamental properties of perovskite, classifications of solar cells, and outlook of their potentials as subcells of tandem photovoltaic devices and large scale applicability.
- single-junction PSC reached Certified 20.1% PCE.
- controlling nucleation and grain growth may provide a more compact and uniform perovskite layer.
- Cl addition adds blue-shifted luminescence and band gap control. (multiple halides term it a wide band-gap cell)
- A hysteresis-free J-V curve can be performed at either very slow or very fast scan rates. Hysteresis during J-V measurements can lead to false PCE values. Additionally, stabilized output at max power should be checked.
- large stability issue for MAPbI3 as in the precence of water it will decompose into PbI2 and CH3NH3I. In the dark it forms a hydrate: MA4PbI6·2H2O. However, this stability can be mitigated by using a mixed halide design (doping the perovskite with Br and Cl).
A brief history of perovskite materials for photovoltaic applications
Source and Full Text: 1. P. Gao, M. Grätzel, and M. K. Nazeeruddin, "Organohalide lead perovskites for photovoltaic applications", Energy & Environmental Science. 7, pp. 2448, (2014)..
There are only few semiconducting materials that have been shaping the progress of third generation photovoltaic cells as much as perovskites. Although they are deceivingly simple in structure, the archetypal AMX3-type perovskites have built-in potential for complex and surprising discoveries. Since 2009, a small and somewhat exotic class of perovskites, which are quite different from the common rock-solid oxide perovskite, have turned over a new leaf in solar cell research. Highlighted as one of the major scientific breakthroughs of the year 2013, the power conversion efficiency of the title compound hybrid organic–inorganic perovskite has now exceeded 18%, making it competitive with thin-film PV technology. In this minireview, a brief history of perovskite materials for photovoltaic applications is reported, the current state-of-the-art is distilled and the basic working mechanisms have been discussed. By analyzing the attainable photocurrent and photovoltage, realizing perovskite solar cells with 20% efficiency for a single junction, and 30% for a tandem configuration on a c-Si solar cell would be realistic.
Focused Papers-Solar Cell Group 1
Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells
Source and Text through ILLiad Interlibrary Loan: Nam Joong Jeon,Jun Hong Noh,Young Chan Kim,Woon Seok Yang,Seungchan Ryu & Sang Il Seok,"Solvent engineering for high-performance inorganic–organic hybrid perovskite solar cells", Nature Materials 13, pp. 897–903, (2014).
- Abstract: Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process. We used CH3NH3 Pb(I1 − xBrx)3 (x = 0.1–0.15) as the absorbing layer and poly(triarylamine) as a hole-transporting material. The use of a mixed solvent of γ-butyrolactone and dimethylsulphoxide (DMSO) followed by toluene drop-casting leads to extremely uniform and dense perovskite layers via a CH3NH3I–PbI2–DMSO intermediate phase, and enables the fabrication of remarkably improved solar cells with a certified power-conversion efficiency of 16.2% and no hysteresis. These results provide important progress towards the understanding of the role of solution-processing in the realization of low-cost and highly efficient perovskite solar cells.
High efficiency CH3NH3PbI(3−x)Clx perovskite solar cells with poly(3-hexylthiophene) hole transport layer
Source and Full Text: Francesco Di Giacomo, Stefano Razza, Fabio Matteocci, Alessandra D'Epifanio, Silvia Licoccia, Thomas M. Brown, Aldo Di Carlo,"High efficiency CH3NH3PbI(3−x)Clx perovskite solar cells with poly(3-hexylthiophene) hole transport layer", Journal of Power Sources 251, pp. 152–156, (2014).
- Not useful for this project. Organic HTMs are have very poor stability. They tend to absorb moisture and allow the perovskite itself to come into contact with moisture which leads to degradation of the cell. PCE significantly diminishes.
Influence of compact TiO2 layer on the photovoltaic characteristics of the organometal halide perovskite-based solar cells
Source and Text through ILLiad Interlibrary Loan: Xiaomeng Wang, Yanling Fang, Lei He, Qi Wang, Tao Wu,"Influence of compact TiO2 layer on the photovoltaic characteristics of the organometal halide perovskite-based solar cells", Materials Science in Semiconductor Processing 27, pp. 569-576, (2014).
- Abstract: A series of perovskite-based solar cells were fabricated wherein a compact layer (CL) of TiO2 of varying thickness (0–390 nm) was introduced by spray pyrolysis deposition between fluorine-doped tin oxide (FTO) electrode and TiO2 nanoparticle layer in perovskite-based solar cells. Investigations of the CL thickness-dependent current density–voltage (J–V) characteristics, dark current, and open circuit voltage (Voc) decays showed a similar trend for thickness dependence. A CL thickness of 90 nm afforded the perovskite-based solar cell with the maximum power conversion efficiency (η, 3.17%). Furthermore, two additional devices, perovskite-based solar cell omitting hole transporting materials layer and cell without the TiO2 nanoparticles, were designed and fabricated to study the influence of the CL thickness on different electron transport paths in perovskite-based solar cells. Solar cells devoid of TiO2 nanoparticles, but with perovskite and organic hole-transport materials (HTMs), exhibited sustained improvement in photovoltaic performances with increase in the thickness of CL, which is in contrast to the behavior of classical perovskite-based solar cell and common solid state solar cell which showed optimal photovoltaic performances when the thickness of CL is 90 nm. These observations suggested that TiO2 nanoparticles play a significant role in electron transport in perovskite-based solar cells.
Gas-assisted preparation of lead iodide perovskite films consisting of a monolayer of single crystalline grains for high efficiency planar solar cells
Source and Text through ILLiad Interlibrary Loan: Fuzhi Huang, Yasmina Dkhissi, Wenchao Huang, Manda Xiao, Iacopo Benesperi, Sergey Rubanov, Ye Zhu, Xiongfeng Lin, Liangcong Jiang, Yecheng Zhou, Angus Gray-Weale, Joanne Etheridge, Christopher R. McNeill, Rachel A. Caruso, Udo Bacha, Leone Spiccia, Yi-Bing Cheng,"Gas-assisted preparation of lead iodide perovskite films consisting of a monolayer of single crystalline grains for high efficiency planar solar cells", Nano Energy 10, pp. 10-18, (2014).
- Not useful for this project.
Charge Transport and Recombination in Perovskite (CH3NH3)PbI3 Sensitized TiO2 Solar Cells
Source and Full Text: Yixin Zhao and Kai Zhu,"Charge Transport and Recombination in Perovskite (CH3NH3)PbI3 Sensitized TiO2 Solar Cells", J. Phys. Chem. Lett. 4, pp. 2880–2884, (2013).
- Abstract: We report on the effect of TiO2 film thickness on the charge transport, recombination, and device characteristics of perovskite (CH3NH3)PbI3 sensitized solar cells using iodide-based electrolytes. (CH3NH3)PbI3 is relatively stable in a nonpolar solvent (e.g., ethyl acetate) with a low iodide concentration (e.g., 80 mM). Frequency-resolved modulated photocurrent/photovoltage spectroscopies show that increasing TiO2 film thickness from 1.8 to 8.3 μm has little effect on transport but increases recombination by more than 10-fold, reducing the electron diffusion length from 16.9 to 5.5 μm, which can be explained by the higher degree of iodide depletion within the TiO2 pores for thicker films. The changes of the charge-collection and light-absorption properties of (CH3NH3)PbI3 sensitized cells with varying TiO2 film thickness strongly affect the photocurrent density, photovoltage, fill factor, and solar conversion efficiency. Developing alternative, compatible redox electrolytes is important for (CH3NH3)PbI3 or similar perovskites to be used for potential photoelectrochemical applications.
Optical bleaching of perovskite (CH3NH3)PbI3 through room-temperature phase transformation induced by ammonia
Source and Full Text: Yixin Zhao and Kai Zhu,"Optical bleaching of perovskite (CH3NH3)PbI3 through room-temperature phase transformation induced by ammonia", Chemical Communications 13, pp. 1605-1607, (2014).
- Not useful for this project
Solid-State Mesostructured Perovskite CH3NH3PbI3 Solar Cells: Charge Transport, Recombination, and Diffusion Length
Source and Full Text: Yixin Zhao, Alexandre M. Nardes, and Kai Zhu,"Solid-State Mesostructured Perovskite CH3NH3PbI3 Solar Cells: Charge Transport, Recombination, and Diffusion Length", J. Phys. Chem. Lett. 5, pp. 490–494, (2014).
- Abstract: We report on the effect of TiO2 film thickness on charge transport and recombination in solid-state mesostructured perovskite CH3NH3PbI3 (via one-step coating) solar cells using spiro-MeOTAD as the hole conductor. Intensity-modulated
photocurrent/photovoltage spectroscopies show that the transport and recombination properties of solid-state mesostructured perovskite solar cells are similar to those of solidstate dye-sensitized solar cells. Charge transport in perovskite cells is dominated by electron conduction within the mesoporous TiO2 network rather than from the perovskite layer. Although no significant film-thickness dependence is found for transport and recombination, the efficiency of perovskite cells increases with TiO2 film thickness from 240 nm to about 650−850 nm owing primarily to the enhanced light harvesting. Further increasing film thickness reduces cell efficiency associated with decreased fill factor or photocurrent density. The electron diffusion length in mesostructured perovskite cells is longer than 1 μm for over four orders of magnitude of light intensity.
Low-Temperature and Solution-Processed Amorphous WOX as Electron-Selective Layer for Perovskite Solar Cells
Source and Full Text: Kai Wang, Yantao Shi, Qingshun Dong, Yu Li, Shufeng Wang, Xufeng Yu, Mengyao Wu, and Tingli Ma,"Low-Temperature and Solution-Processed Amorphous WOX as Electron-Selective Layer for Perovskite Solar Cells", J. Phys. Chem. Lett. 6, pp. 755–759, (2015).
- Study demonstrates WOx is an alternative to TiO2 for the ETM material.
Crystal Morphologies of Organolead Trihalide in Mesoscopic/Planar Perovskite Solar Cells
Source and Full Text: Yuanyuan Zhou, Alexander L. Vasiliev, Wenwen Wu, Mengjin Yang, Shuping Pang, Kai Zhu, and Nitin P. Padture,"Crystal Morphologies of Organolead Trihalide in Mesoscopic/Planar Perovskite Solar Cells", J. Phys. Chem. Lett. 6, pp. 2292–2297, (2015).
- Abstract: The crystal morphology of organolead trihalide perovskite (OTP) light absorbers can have profound influence on the perovskite solar cells (PSCs) performance. Here we have used a combination of conventional transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), in cross-section and plan-view, to characterize the morphologies of a solution-processed OTP (CH3NH3PbI3 or MAPbI3) within mesoporous TiO2 scaffolds and within capping and planar layers. Studies of TEM specimens prepared with and without the use of focused ion beam (FIB) show that FIBing is a viable method for preparing TEM specimens. HRTEM studies, in conjunction with quantitative X-ray diffraction, show that MAPbI3 perovskite within mesoporous TiO2 scaffold has equiaxed grains of size 10–20 nm and relatively low crystallinity. In contrast, the grain size of MAPbI3 perovskite in the capping and the planar layers can be larger than 100 nm in our PSCs, and the grains can be elongated and textured, with relatively high crystallinity. The observed differences in the performance of planar and mesoscopic-planar hybrid PSCs can be attributed in part to the striking differences in their perovskite-grain morphologies.
Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode
Source and Full Text: Huawei Zhou, Yantao Shi, Qingshun Dong, Hong Zhang, Yujin Xing, Kai Wang, Yi Du, and Tingli Ma,"Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode", J. Phys. Chem. Lett. 5, pp. 3241–3246, (2014).
- Abstract: Low cost, high efficiency, and stability are straightforward research challenges in the development of organic–inorganic perovskite solar cells. Organolead halide is unstable at high temperatures or in some solvents. The direct preparation of a carbon layer on top becomes difficult. In this study, we successfully prepared full solution-processed low-cost TiO2/CH3NH3PbI3 heterojunction (HJ) solar cells based on a low-temperature carbon electrode. Power conversion efficiency of mesoporous (M-)TiO2/CH3NH3PbI3/C HJ solar cells based on a low-temperature-processed carbon electrode achieved 9%. The devices of M-TiO2/CH3NH3PbI3/C HJ solar cells without encapsulation exhibited advantageous stability (over 2000 h) in air in the dark. The ability to process low-cost carbon electrodes at low temperature on top of the CH3NH3PbI3 layer without destroying its structure reduces the cost and simplifies the fabrication process of perovskite HJ solar cells. This ability also provides higher flexibility to choose and optimize the device, as well as investigate the underlying active layers.
Review Articles Group 2
Advancements in all-solid-state hybrid solar cells based on organometal halide perovskites
Source and Full Text: Shaowei Shi, Yongfang Li, Xiaoyu Li, and Haiqiao Wang, "Advancements in all-solid-state hybrid solar cells based on organometal halide perovskites", Material horizons 2 pp. 378-405, (2015).
- Very useful review article. Includes various up to date deposition methods for PSCs.
- Perovskites can act as a light absorber as well as a bipolar transport of both holes and electrons.
- In depth description of benefits of potential device architectures for PSCs.
- Mesoporous metal oxide n-type layers like TiO2. FTO/bl-TiO2/mp-TiO2(rutile)/MAPbX3/spiro-MeOTAD/Au (X=I,Br,Cl)
- Meso-superstructured designs using Al2O3. FTO/bl-TiO2/mp-Al2O3/MAPbX3/spiro-MeOTAD/Ag (X=I,Br,Cl)
- Various HTMs are discussed, Spiro-MeOTAD so far contributes to the highest PCE, however, P3HT, and PTAA are viable polymer based HTMs.
- Main limiting factor for practical application is the sensitivity to moisture and elevated temperature.
Solution Chemistry Engineering toward High-Efficiency Perovskite Solar Cells
Source and Full Text: Yixin Zhao and Kai Zhu,"Solution Chemistry Engineering toward High-Efficiency Perovskite Solar Cells", J. Phys. Chem. Lett. 5, pp. 4175–4186, (2014).
- Abstract: Organic and inorganic hybrid perovskites (e.g., CH3NH3PbI3) have emerged as a revolutionary class of light-absorbing semiconductors that has demonstrated a rapid increase in efficiency within a few years of active research. Controlling perovskite morphology and composition has been found critical to developing high-performance perovskite solar cells. The recent development of solution chemistry engineering has led to fabrication of greater than 15–17%-efficiency solar cells by multiple groups, with the highest certified 17.9% efficiency that has significantly surpassed the best-reported perovskite solar cell by vapor-phase growth. In this Perspective, we review recent progress on solution chemistry engineering processes and various control parameters that are critical to the success of solution growth of high-quality perovskite films. We discuss the importance of understanding the impact of solution-processing parameters and perovskite film architectures on the fundamental charge carrier dynamics in perovskite solar cells. The cost and stability issues of perovskite solar cells will also be discussed.
Review of recent progress in chemical stability of perovskite solar cells
Source and Full Text: Guangda Niu, Xudong Guo and Liduo Wang,"Review of recent progress in chemical stability of perovskite solar cells", J. Mater. Chem. 3(17), (2014).
- Perovskites: ease of fabriaction, small band-gap, high extinction coefficients, and high carrier mobility - Thin film
- Record PCE is 20.1%
- Power conversion efficiency(has been main focus) and device stability(future direction) are largest issues currently
- PCSs are susceptible to: Oxygen+moisture, UV light, the solution process(solvents, solutes, additives), and temperature.
- CH3NH3PbI3 started to decompose at a humidity of 55%, dark brown -> yellow
- CH3NH3Pb(I1-xBrx)3 (x = 0.2, 0.29) exhibits improved stability. (vs moisture, solutions, and temperature)
- This paper deals with organic HTM/no HTM(no HTM yeilded 10.5% PCE) layers.
- This paper is useful for understanding stability although my direction is using inorganic HTM layers which prevents many of the issues discussed here.
Focused Papers-Solar Cell Group 2
Summaries to be added
Study on the stability of CH3NH3PbI3 films and the effect of post-modification by aluminum oxide in all-solid-state hybrid solar cells
Sub-150C processed meso-superstructured perovskite solar cells with enhanced efficiency
Efficient organometal trihalide perovskite planar-heterojunction solar cells on flexible polymer substrates
Carbon Nanotube/Polymer Composites as a Highly Stable Hole Collection Layer in Perovskite Solar Cells
Source: Habisreutinger SN, Leijtens T, Eperon GE, Stranks SD, Nicholas RJ, Snaith HJ. "Carbon Nanotube/Polymer Composites as a Highly Stable Hole Collection Layer in Perovskite Solar Cells" Nano Lett. 2014 Oct 8;14(10):5561–8.
Efficient planar heterojunction perovskite solar cells by vapour deposition
Environmentally responsible fabrication of efficient perovskite solar cells from recycled car batteries
- Process is described as thus:
- Harvest material from the anodes and cathodes of car battery
- Synthesize PbI2 from the collected materials
- Deposite lead iodide perovskite nanocrystals
- XRD and PL response are shown to be near equivalent for PSCs fabriacated from both car batteries and high purity commercial PbI2
Low-Temperature Processed Electron Collection Layers of Graphene/TiO2 Nanocomposites in Thin Film Perovskite Solar Cells
New Physical Deposition Approach for Low Cost Inorganic Hole Transport Layer in Normal Architecture of Durable Perovskite Solar Cells
-This work focused on fabrication of all inorganic hole and electron transport materials based perovskite solar cells
- Durable perovskite solar cells with stable efficiency up to 60 days reported is achieved.
- The rotational angular Sputtering technique introduced as a sufficient method in deposition of inorganic ETM or HTMs on perovskite layers
- Well-coverage deposition of NiO (nickel oxide) layer on perovskite layer successful conducted
- This method introduced as an appropriate method in deposition of NiO on perovskite layers even containing pinholes in perovskite layers.
Metal/Metal-Oxide Interfaces: How Metal Contacts Affect the Work Function and Band Structure of MoO3
Small Photocarrier Effective Masses Featuring Ambipolar Transport in Methylammonium Lead Iodide Perovskite: A Density Functional Analysis
Comparison of transparent conductive indium tin oxide, titanium-doped indium oxide, and fluorine-doped tin oxide films for dye-sensitized solar cell application
Screening procedure for structurally and electronically matched contact layers for high-performance solar cells: hybrid perovskites
Research improves efficiency from larger perovskite solar cells
Focused Papers-3D Printing
Open-Source Syringe Pump Library
Combining 3D printing and liquid handling to produce user-friendly reactionware for chemical synthesis and purification
PV Nano Cell’s NanoMetal Inks Write Up 2016 as the Year of 3D Printed Electronics
Source and Text: Davide,"PV Nano Cell’s NanoMetal Inks Write Up 2016 as the Year of 3D Printed Electronics", News, 3D Printing (2016).
- 3D printed electronics, both for prototyping of PCBs and end use wearable and IoT products
- silver and copper based single crystal nano-metric conductive inks
- Impact: 3D print electronic-capable products -> such as photovoltaics and printed circuit boards
- competitive Low cost 1/3 of other inks on market
- PVN has a production capacity of hundreds of kilograms and is specifically targeting the market for mass end-use products and parts.