以金属氯化物作为金属源,硫脲为硫源,乙二醇为溶剂,聚乙烯吡咯烷酮(PVP)为表面活性剂,采用溶剂热法在较低反应温度下合成了Cu2ZnSnS4(CZTS)粉末。利用X射线衍射仪(XRD)、拉曼光谱(Raman)、扫描电子显微镜(SEM)、高分辨透射电子显微镜(HRTEM)对样品的结构和形貌进行表征。利用紫外-可见光谱(UV-Vis)对样品的光学性能进行研究。结果表明,180 ℃反应25小时的样品均为锌黄锡矿CZTS颗粒,颗粒形貌为表面花状的微球。当体系中PVP含量为0.2 g时,微球尺寸约为2.5 μm。当体系中PVP含量为03 g,0.4 g,0.5 g时,微球尺寸大约为1.1 μm。其中,PVP含量为0.4 g的样品分散性较好,在可见区有明显的吸收,用外延法得到其禁带宽度约为1.45 eV,与太阳能电池所需的最佳禁带宽度接近。

Cu2ZnSnS4(CZTS)powders were synthesized at lower temperature by solvothermal method in ethylene glycol with metal chloride as metal precursors,thiourea as sulfur source,and polyvinylpyrrolidone(PVP) as surfactant.The crystal structures and morphology of the samples were characterized by X-ray diffraction (XRD),Raman spectroscopy,Scanning Electron Microscope (SEM),and Transmission Electron Microscopy (TEM).The optical properties of the samples were investigated by UV-Vis spectrum(UV-Vis).The results indicate that kesterite CZTS particles were prepared at 180 ℃ for 25 h.Under this condition,the microspheres with flower-like surface were obtained.The diameters of the microspheres were about 2.5 μm for the sample prepared at 0.2 g of PVP in the reaction system.While the diameters of the microspheres were about 1.1 μm for the samples prepared at 0.3 g,0.4 g and 0.5 g of PVP.The sample prepared at 0.4 g of PVP was more disperse and possessed an obvious absorption in the visible region.The band gap is estimated to be about 1.45 eV by extrapolation.Such a band gap is close to the optimum band gap for solar cell.