An analytical solution for the collection efficiency of solar-cell emitters with arbitrary doping profile

An analytical expression consisting of a rapidly converging integral series is derived to calculate the collection efficiency of solar-cell emitters in steady state. This general expression applies to emitters which feature an arbitrary doping profile and heavily doped regions. It does not rely on a particular description of the relation between minority-carrier transport parameters and doping density. It is shown that most of the earlier approximations are included in the solution. To demonstrate the advantages and feasibility of this approach, calculation results are compared with approximate and numerical solutions, and with exact solutions when available.>