Synthesis and Characterization of Cu₃(Sb_1–xAs_x)S₄ Semiconducting Nanocrystal Alloys with Tunable Properties for Optoelectronic Device Applications

A synthetic method for producing monodisperse Cu 3 (Sb 1– x As x )S 4 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 Cu 3 AsS 4 NC thin films compared to the more well-studied Cu 3 SbS 4 composition. Interestingly, this improvement in photocurrent is observed despite the increased optical band gap of the arsenic-rich compositions. These results suggest Cu 3 AsS 4 and arsenic-rich compositions of Cu 3 (Sb 1– x As x )S 4 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.