Dependence of the I–V characteristics of amorphous silicon solar cells on illumination intensity and temperature

Current-voltage characteristics of amorphous silicon (a-Si) solar cells are systematically investigated as functions of the illumination intensity and ambient temperature. The principle of superposition of the short-circuit current and the dark current, which is usually assumed for crystalline silicon solar cells, is not applicable to a-Si solar cells. It is shown, that the output current of a-Si solar cells at a given illumination intensity E₂mW/cm²I_E2(V) is expressed by a relatively simple equation, I_E2(V) = I_d(V) + (_{E2/100) × (I100(V) — Id(V))}, when the series resistance of the solar cells is negligible. Here, I_d(V) is the dark current, I₁₀₀(V) is the output current at an illumination of 100 mW/cm², and V is the applied voltage. Empirical formula to describe the dependence of the current-voltage characteristics on the illumination intensity and the temperature are presented and discussed.