Back Contact Work Function Modification for Increasing CZTSSe Thin Film Photovoltaic Efficiency

摘要

Techniques for increasing conversion efficiency of thin film photovoltaic devices through back contact work function modification are provided. In one aspect, a photovoltaic device is provided having a substrate; a back contact on the substrate, wherein at least a portion of the back contact has a work function of greater than about 4.5 electron volts; an absorber layer on a side of the back contact opposite the substrate; a buffer layer on a side of the absorber layer opposite the back contact; and a top electrode on a side of the buffer layer opposite the absorber layer. The absorber layer preferably has thickness that is less than a depletion width+an accumulation width+a carrier diffusion length.