The minority carrier transport length (L) is a critical parameter limiting the performance of inexpensive Cu2O-ZnO photovoltaic devices. In this work, this length is determined for electrochemically deposited Cu2O by linking the optical carrier generation profile from front and back incident-photon-to-electron conversion efficiency (IPCE) measurements to a one dimensional carrier transport model. A transport length of ~ 400 nm is estimated. This critical length explains the losses typically presented by these devices. The consequences of this L on device design with the aim of improving solar cell performance are described.
We present experimental and theoretical studies of a nanopatterned photonic crystal formed between the bulk heterojunction blend,
poly-3-hexylthiophene:[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) and nanocrystalline zinc oxide (nc-ZnO). The nanopattern is fabricated using the Pattern Replication in Non-wetting
Templates (PRINT) technique. We summarize the fabrication method and show how it can be used to make a highly ordered hexagonal array of photovoltaic P3HT:PCBM posts. We also discuss theoretical studies of optical absorption for the nanopattern design that result in a 22% enhancement over a conventional planar cell. Spectroscopic ellipsometry is also used to determine the optical constants of solar cell materials that are used in the optical model. Finally, we
calculate the local exciton creation profile within the photoactive nanopattern to relate the nanostructured geometry to electrical performance.