Synthesis and characterization of Cu2ZnSnS4 from Cu2SnS3 and ZnS compounds

The Cu 2 ZnSnS 4 (CZTS) powders are successfully synthesized by using ZnS and Cu 2 SnS 3 as raw materials directly without any intermediate phase at 450 °C for 3 h in Ar atmosphere. The crystalline structure, morphology and optical properties of the CZTS powders are characterized by X-ray diffraction (XRD), Raman spectrum, field emission scanning electron microscopy (FESEM) and ultraviolet-visible (UV-vis) spectrophotometer, respectively. The results show that the band gap of the obtained CZTS is 1.53 eV. The CZTS film is fabricated by spin coating a mixture of CZTS powders and novolac resin with a weight percentage of 30%. The photoelectrical properties of such CZTS films are measured, and the results show an incident light density of 100 mW·cm −2 with the bias voltage of 0.40 V, and the photocurrent density can approach 9.80×10 −5 A·cm 2 within 50 s, giving an on/off switching ratio of 1.64.