ABSTRACT
Loferski, Prince and Shockley have theoretically investigated the conversion efficiency in p-n junction photovoltaic solar energy converters as a function of the energy gap of the semiconductor. These investigations show that the conversion efficiency vs. energy gap plot shows a maximum around 1·1–1·3 eV.
Taking into account the fact that the solar converter is not only exposed to black body radiation but also to scattered radiation from the sky, we have recalculated the optimum energy gap and come out with a value of 1·6–2·0 eV. Our calculations indicate that silicon once considered the best material from efficiency considerations, does not hold good any more. Thus a semiconductor material with energy gap of around 2·0 eV. will have a higher efficiency coupled with several other advantages.