New architecture for high-efficiency polymer photovoltaic cells using solution-based titanium oxide as an optical spacer

Polymer photovoltaic cells with power conversion efficiencies approaching 5% have been fabricated using titanium oxide (TiOx) as an optical spacer (see Figure). Solar cells with a TiOx layer (deposited via a sol-gel process) between the active layer and the electron-collecting aluminum electrode exhibit approximately a 50 % enhancement in short-circuit current compared to similar devices without the optical spacer, as a result of modification of the spatial distribution of the light intensity inside the device.