Chapter IA-1 - Principles of Solar Cell Operation

Abstract

Publisher Summary This chapter discusses the photovoltaic energy conversion in solar cells. In solar cells with a simple geometry, light rays enter the cell through the front surface and, if not absorbed, leave through the rear surface of the cell. More sophisticated arrangements exist that extend the path of light inside the cell, and they are usually referred to as optical confinement or light trapping. In crystalline or amorphous silicon solar cells, light trapping is used to reduce the thickness of the cell without lowering the light absorption within the cell. Light trapping can also be used to enhance the open-circuit voltage. In practical silicon solar cells, the emitter is generally fabricated by diffusion of impurities into the semiconductor wafer. This creates a thin layer where the impurity gradient is very high and the approximation of constant doping concentration does not hold. Simultaneously, the continuity and current equations do not combine into a second-order differential equation with constant coefficients, and a simple analytical solution cannot be found.