Synthesis and Characterization of Cu3(Sb1–x As x )S4 Semiconducting Nanocrystal Alloys with Tunable Properties for Optoelectronic Device Applications

A synthetic method for producing monodisperse Cu3(Sb1–x As x )­S4 nanocrystals (NCs) with highly tunable semiconducting properties is discussed. Additionally, significant improvement in collectible photocurrent is observed for arsenic-rich compositions, with a 10-fold improvement in photocurrent density from Cu3AsS4 NC thin films compared to the more well-studied Cu3SbS4 composition. Interestingly, this improvement in photocurrent is observed despite the increased optical band gap of the arsenic-rich compositions. These results suggest Cu3AsS4 and arsenic-rich compositions of Cu3(Sb1–x As x )­S4 may yield higher photocurrent densities for solar conversion devices. Furthermore, the simple and robust synthesis, scalable spray coating strategy, and highly tunable nature of the NCs provides a foundation encompassing numerous fields requiring inexpensive and earth-abundant semiconducting materials.