Antimony Sulfobromide Nanowire Bundles Exhibiting Ambipolar Photoelectrochemical Photocurrent Switching

Chalcohalides have emerged as novel semiconducting materials for fabricating electronic, optoelectronic, and electrochemical devices. Particularly, antimony (Sb)-based chalcohalides have attracted attention as solar energy conversion and thermoelectrics. Herein, the first report on the colloidal synthesis of antimony sulfobromide (SbSBr) nanowire bundles (NBs) via a hot-injection method is reported. The as-synthesized SbSBr NBs exhibited high size and shape uniformity and excellent phase purity. The growth behavior of the SbSBr NBs is systematically investigated by varying the reaction time, revealing a sequential structure and phase transformation from amorphous spherical nanoparticles to crystalline NBs. The optical bandgap and energy levels of the conduction and valence band edges are characterized in conjunction with first-principles calculations to understand the energy diagram of SbSBr NBs. SbSBr NB-based photoelectrodes are fabricated via a solution-based fabrication process to investigate the photoelectrochemical properties of nanosized SbSBr. The fabricated photoelectrodes exhibited a photoelectrochemical photocurrent switching behavior under anodic and cathodic biases and simulated solar illumination, enabling the fabrication of a two-channel optoelectronic demultiplexer as a proof-of-concept application. The successful synthesis of colloidal SbSBr and systematic investigation of its photoelectrochemical properties open new opportunities for using Sb-based chalcohalide NBs in developing optoelectronic and photoelectrochemical devices.