Detailed analysis of the factors affecting emitter recombination in solar cells through the small-signal voltage decay method

A general solution to the coupled time-dependent diffusion equations that describe minority carrier decay in any open-circuit solar cell is presented. Emitter bandgap narrowing is taken into account. The effective lifetime derived from voltage decay measurements can be accurately related to recombination rates in the emitter and in the base. In order to obtain closed-form solutions, it is assumed that the emitter doping profile could be expressed as a power law. The minority carrier lifetime and mobility in the emitter are assumed constant. Theoretical results are compared with computer simulations