| Conceptual Reference Database for Building Envelope Research |
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| Essay:Brief history of Si solar cell conversion efficiency"Currently, the vast majority of commercial solar cells are produced out of silicon. Henri Becquerel discovered in 1836 the photovoltaic effect or the capacity of some material systems to generate a voltage when illuminated. Pearson, Chapman, and Fuller from the Bell Laboratories, first reported the modern silicon solar cell in 1954 demonstrating a 5¨C6% efficiency [7]. In the 1960s, the first commercial solar cells were produced out of silicon. These sells were primary used for powering satellites but were too expensive for other application. The energy crisis in the 1970s initiated considerable technical progress which resulted in significant increase in cell conversion efficiencies and cost reductions due to government support of R&D in alternative energies projects. Nowadays, the efficiency of silicon solar cells under laboratory conditions is approaching the theoretical limit of 29%." -- Mitra?inovi?, A., 2011, Photo-catalytic properties of silicon and its future in photovoltaic applications
"Assuming a 12% conversion efficiency (standard conditions) and 1700 kWh/m2 per year of available sunlight energy (the U.S. average is 1800), the calculated payback time is about four years for existing polycrystalline silicon photovoltaic systems. Projecting improvements 10 years into the future, where the author assumes a constant supply of solar grade silicon feedstock by conventional processes and 14% efficiency, energy payback is reduced to about two years." -- Mitra?inovi?, A., 2011, Photo-catalytic properties of silicon and its future in photovoltaic applications | ||||||||||