Synthesis and characterization of Cu_2ZnSnS_4 from Cu_2SnS_3 and ZnS compounds

The Cu2 Zn Sn S4（CZTS） powders are successfully synthesized by using Zn S and Cu2 Sn S3 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 e V.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 m W·cm-2 with the bias voltage of 0.40 V,and the photocurrent density can approach 9.80×10-5 A·cm2 within 50 s,giving an on/off switching ratio of 1.64.