Modelling charge transport lengths in heterojunction solar cells

A drift-diffusion model is used to estimate the minority carrier transport length and depletion width in heterojunction solar cells from measured external quantum efficiency (EQE) data. The model is applied to Cu2O-ZnO heterojunctions synthesized by electrodeposition and thermal oxidation, and the electron drift and diffusion lengths are estimated: L-drift approximate to 110 nm for electrodeposited Cu2O and L-drift approximate to 2790 nm and L-diff approximate to 310 nm for thermally oxidized Cu2O. Better fitting of EQE data is obtained than with traditional models that neglect recombination in the depletion region. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4771981]