Abstract
We fabricated pure kesterite Cu2ZnSnS4 (CZTS) nanocrystals for solar cells by solvothermal synthesis. We investigated the effects of 0.5–2 mg/mL glycine complexing agent on the nanocrystals’ properties by comprehensive spectroscopic and microscopic analysis, focusing on structural, morphological, compositional, and chemical properties. By controlling the glycine concentration, we obtained complete single-phase nanocrystals: high purity, good crystallinity, and copper-poor and Zn-rich composition. The nanocrystal diameter ranged ~50–60 nm. Thin films based on the nanocrystals were smooth, compact, free of cracks and holes, and had a grain size of up to 2.8 μm. The nanocrystals have an optical band gap between 1.51 and 2.27 eV and an absorption coefficient greater than 104 cm−1. The nanocrystal properties indicate promise for high-efficiency CZTS solar cells.