Project title: A Multiscale Study of Extremely Thin Absorber solar cells

Supervisors: Andrew Horsfield and Nicholas Harrison

Project description:

The ETA solar cell consists of a transparent electrode, a nanowire structured semiconductor layer (TiO2) coated with an extremely thin photon absorber layer (CdSe) and surrounded by a polymer hole conductor, and then another electrode (Au). CdSe absorbs photons to produce excitons, which then split with the electron hopping into the conduction band of the n-type TiO2 and the hole into the valence band of the p-type polymer. The idea is to conduct the electron/hole pair away from the absorber as quickly as possible, before they recombine, thereby maximizing the yield of charges, and hence efficiency of the device. Firstly, we will study the absorption of light in the CdSe absorber layer learning how nanowire shape, length and coating thickness influence absorption. This will be acheived using Finite-Difference Time-Domain (FDTD) simulations and Mie Theory. Secondly, using hybrid density-functional theory (implemented in CRYSTAL) we will study the excitation spectrum of CdSe and how it is modified by interfaces to the TiO2 and polymer. Thirdly, we will use density-functional theory as an input to Marcus theory to understand electron and hole transport in the device.