Size-controlling of Cu2ZnSnS4 nanoparticles: Effects of stabilizing/reducing agents on material properties

Abstract

In this study, Cu2ZnSnS4 (CZTS) nanoparticles with an average size in a range of 10–36 nm were synthesized via solvothermal synthesis using different amounts of polyvinylpyrrolidone (PVP, 3, 5, 7, and 9 mg/mL) stabilizing agent. The effect of the amount of PVP on the CZTS nanoparticles’ structure, phase formation, composition, morphology, and opto-electronic properties were studied using XRD, UV–vis spectroscopy, TEM, FE-SEM, and Raman spectroscopy. Raman spectroscopy and XRD confirmed the formation of a pure kieserite phase with high crystallinity. The nanoparticles exhibited a strong preferential orientation along the [112] crystallographic plane. Using PVP stabilizer at a concentration of 9 mg/mL, a nearly stoichiometric ratio of 2:1:1:4 was achieved. The UV–vis absorption spectroscopy measurements showed an absorption coefficient exceeding 104 cm−1 in the visible light region and energy gap of CZTS nanoparticles between 1.59 eV and 1.82 eV, which is close to the optimum bandgap value for solar cell conversion devices. The TEM study revealed good CZTS nanoparticles crystals with diameters of approximately 10–40 nm depending on the stabilizing agent concentration. Solar cell devices with Al/ZnO: Al/ZnO/CdS/CZTS/Mo structures prepared with CZTS synthesized using PVP stabilizer at a concentration of 9 mg/mL had a maximum Jsc = 9.83 mA/cm2, Voc = 0. 453 V, fill factor = 61.1%, and efficiency of 2.7%.