Minority carrier transport length of electrodeposited Cu2O in ZnO/Cu2O heterojunction solar cells

The minority carrier transport length is a critical parameter limiting the performance of inexpensive Cu2O–ZnO photovoltaic devices. In this letter, this length is estimated to be ∼430 nm for electrochemically deposited Cu2O by linking the cell’s carrier generation profile with back and front incident photon-to-electron conversion efficiency measurements to a one-dimensional transport model. This critical length explains the losses typically presented by these devices and appears to correlate well with the microcrystalline film structure. The consequences of the magnitude of the length on device design with the aim of improving solar cell performance are described.