Environmentally friendly and earth-abundant colloidal chalcogenide nanocrystals for photovoltaic applications

Colloidal semiconducting nanocrystals have been identified as a set of promising and versatile nanostructured building blocks for numerous applications owing to their many attractive merits. While colloidal cadmium and lead chalcogenide nanocrystals have been widely explored for use in a variety of photonic and optoelectronic applications, consideration of the environmental compatibility and earth abundance of the materials has motivated the expansion of the research into environmentally friendly and earth-abundant colloidal semiconducting nanocrystals. The most common non-toxic semiconducting materials that have been extensively studied for photovoltaic applications include iron disulfide (FeS2), copper(I) sulfide (Cu2S), tin sulfide (SnS), tin selenide (SnSe), bismuth sulfide (Bi2S3), as well as ternary and quaternary copper chalcogenides such as copper zinc tin sulfide (Cu2ZnSnS4, CZTS). This feature study highlights the recent advances in colloidal synthetic procedures for FeS2, Cu2S, SnS, SnSe, Bi2S3, and CZTS nanocrystals, followed by examples from the literature of how these materials have been utilized in photovoltaic devices. The scientific challenges associated with the syntheses of these environmentally friendly and earth-abundant colloidal chalcogenide nanocrystals and the prospects for their deployment in photovoltaic applications have also been discussed.