===[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=172378&tag=1 Novel technique for improved power conversion efficiency in PV systems with battery back-up] <ref> Snyman, Danie B., and Johan HR Enslin. "Novel technique for improved power conversion efficiency in PV systems with battery back-up." In Telecommunications Energy Conference, 1991. INTELEC'91., 13th International, pp. 86-91. IEEE, 1991. </ref>===
We introduce the radiative properties of our natural surroundings and demonstrate how the characteristic features of thermal emission, solar irradiation, atmospheric absorption, and sensitivity of the human eye and of plant photosynthesis lead naturally to a set of solar energy materials with well-defined wavelength- and angular-dependent absorptance, emittance, reflectance, and transmittance. Specific discussions are given of antireflection through microstructuring and of overheating protection through thermotropism. The paper ends with a look in the crystal ball at some possible solar materials research in the future.
===[http://www.sciencedirect.com/science/article/pii/S0301421500000872 Energy viability of photovoltaic systems] <ref> Alsema, Erik A., and E. Nieuwlaar. "Energy viability of photovoltaic systems." Energy policy 28, no. 14 (2000): 999-1010. </ref>===
*'''Grid parity''' refers to the lifetime generation cost of the electricity from PV being comparable with the electricity prices for conventional sources on the grid.
*'''grid-connected PV system''' is an electricity generating solar PV system that is connected to the utility grid. A grid-connected PV system consists of solar panels, one or several inverters, a power conditioning unit and grid connection equipment. They range from small residential and commercial rooftop systems to large utility-scale solar power stations.
*'''Sustainable development''' (SD) is a process for meeting human development goals while maintaining the ability of natural systems to continue to provide the natural resources and ecosystem services upon which the economy and society depend