Progression in Grain Size of Novel Photoferroic Absorber Bournonite (CuPbSbS3)

Oliver M Rigby, Budhika G Mendis, Marek Szablewski Durham University, Durham, United Kingdom

Bournonite (CuPbSbS3) is an emerging absorber material for solar cells. While initial solar cell devices with bournonite as an absorber layer are promising, the grain size is a limiting factor restricting current power conversion efficiencies. In this work we synthesise bournonite thin-films through a thiol-amine dissolution of bulk oxides and investigate the effects of temperature on controlling the grain sizes, morphology and phase purity of bournonite thin-films. Higher annealing temperatures of 500°C result in ~3μm grain sizes, without the formation of PbS or CuSbS2 secondary phases. This is a significant improvement over the sub-micrometer grain sizes reported previously, although the larger grain size is achieved at the expense of some surface coverage.