Co-solvent effect on microwave-assisted Cu2ZnSnS4 nanoparticles synthesis for thin film solar cell

Min-Hsueh Chiu

Abstract:

Cu2ZnSnS4 (CZTS) nanoparticles (NPs) were prepared in a one-step microwave-assisted synthesis using a
mixture of trioctylphosphine oxide (TOPO) and oleylamine (OLA) as solvent. The reaction medium was
optimized by varying the TOPO and OLA ratios to control the CZTS NPs formation. The synthesized CZTS NPs
were characterized by X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy, and transmission electron
microscopy techniques. High quality CZTS NPs with composition of Cu1.8Zn1.4SnS3.6, optimum size distribution
in the range of 22 ± 4 nm and band gap of around 1.5 eV were obtained using microwave assisted synthesis
method with OLA:TOPO (1:1) as co-solvent. In the microwave assisted process, the reaction temperature and
time has been reduced significantly to 165 °C and 10 min respectively, as compared with other wet chemical
solvothermal hot injection/ surfactant based methods. Finally, CZTSSe solar cell fabricated from the selenized
microwave-assisted CZTS NPs yielded an efficiency of 4.48%; therefore, the low cost of synthesis of this high
quality CZTS NPs ink and the capability of spraying for large solar cell area is very attractive.