IIa-1 - Principles of Solar Cell Operation

Abstract

This chapter discusses the basic principles of solar cell operation. Photovoltaic energy conversion in solar cells consists of two essential steps. First, absorption of light generates an electron–hole pair. Then, electron and hole are separated by the structure of the device; electrons to the negative terminal and holes to the positive terminal, thus generating electrical power. An ideal solar cell can be represented by a current source connected in parallel with a rectifying diode. The photogenerated current is closely related to the photon flux incident on the cell. It is usually independent of the applied voltage with possible exceptions in the case of a-Si and some other thin-film materials. This chapter discusses the basic concepts of electrical characteristics of solar cells, quantum efficiency, spectral response, and antireflection coating. Solar cell characteristics in practice are also discussed. The chapter elaborates the physical structure of the device, and the dominant electron transport processes that contribute to the energy conversion process. The chapter also explains concepts related to typical solar cell structures, including p–n junction solar cell, uniform emitter and base, diffused emitter, heterojunction cells, the p-i-n structure, and series resistance.