Local Structure Studies of As-Made Cu 2 ZnSnS 4 Nanoparticles

To optimize a device, you must know what it's actually made of. Cu${}_{2}$ZnSnS${}_{4}$ (CZTS) is appealing as a photovoltaic absorber, but small structural variations in a real sample can have a large impact on device performance and reliability. To understand the structure and stoichiometry of CZTS nanoparticles, the authors measure the extended x-ray absorption fine structure of the constituent metals. They find that as-synthesized nanoparticles are not always of the intended composition, but that copper-poor CZTS does retain the kesterite (or stannite) structure, with the possibility to fine-tune functional properties by controlling antisite defects.