电沉积合金预制层后退火制备铜锌锡硫薄膜及其光伏特性

摘要

Cu2ZnSnS4 (CZTS) thin films for the absorber of thin film solar cells were prepared by annealling of electrodeposited copper zinc tin alloy. CZTS films were characterized by energy dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction, Raman scttering and photoelectrochemical measurement. The results show that with the increase of molar ratio of n(Cu)/n(Zn+Sn), FWHM of (112) peak increases firstly and then decreases. CZTS thin film with the molar ratios of n(Cu)/n(Zn+Sn)=0.83 and n(Zn)/n(Sn)=1.31 has the optimal performance. The second phases exists in Cu-poor/Zn-poor, Cu-poor/Zn-rich and Cu-rich/Zn-rich CZTS thin films are SnS2, ZnS and Cu-S, respectively. The second phase has significant influence on photoelectrochemical property of CZTS thin films, Cu-poor/Zn-rich CZTS thin films have stable and superior photo-current density (the maximum is 0.6 mA/cm2).Based on optimal composition, the solar cell fabricated with the CZTS thin film shows conversion efficiency of 3.27%.%采用电沉积铜锌锡(Cu-Zn-Sn,CZT)合金预制层后退火制备薄膜太阳电池用吸收层材料铜锌锡硫(Cu2ZnSnS4,CZTS).利用扫描电镜、X线能量色散谱仪、X线衍射仪、拉曼光谱等检测方法对不同预制层成分下制备的CZTS薄膜的表面形貌、成分和物相结构进行表征与分析.研究结果表明:随着预制层中铜摩尔分数的增加,CZTS薄膜(112)面衍射峰半峰宽呈现先减小后增大的趋势,在物质的量比n(Cu)/n(Zn+Sn)=0.83和n(Zn)/n(Sn)=1.31的条件下获得半峰宽最小、结晶性能最好的CZTS薄膜;贫铜贫锌条件下制备的薄膜中存在SnS2二次相,贫铜富锌条件下制备的薄膜中存在少量ZnS二次相;富铜富锌条件下制备的薄膜中存在Cu-S二次相;二次相对薄膜光电响应具有重要影响,贫铜富锌的样品光电响应性能较好,无光电流衰减现象,光电流密度最大可达到0.6 mA/cm2;最优成分下制备的CZTS太阳电池在100 mW/cm2光照条件下获得光电转换效率为3.27%.