Cd掺杂的Cu_2ZnSnS_4光伏材料的发光光谱及其太阳能电池器件特性

利用溅射-硫化法制备了一系列不同Cd含量掺杂的铜锌锡硫薄膜材料,并获得了转换效率最高达10.65%的薄膜太阳能电池。利用扫描电子显微镜、变温光致发光谱、变激发密度发光光谱对材料进行了表征,分析了电池器件的电容-电压、电流-电压特性。材料的发光峰峰值显示出反常的温度依赖性,载流子表现出强烈的局域化特征。Cd的适当掺入可以抑制较深缺陷的形成并减小发光峰值和带隙值之间的能量差,从而减小了器件开路电压的损失,有利于器件效率的提升。

Photoluminescence Properties Cd-doped Cu2 ZnSnS4 Thin Films and Performance of The Solar Cells

Cu2 ZnSnS4 thin films with different Cd compositions were prepared using sputtering-sulfu-ration method. The best device with efficiency as high as 10. 65% was achieved. The scanning elec-tron microscope, temperature dependent photoluminescence, excitation power dependent photolumi-nescence were employed to character the materials and the capacitance-voltage and current-voltage characteristics of the solar cells were studied. It is revealed that the photoluminescence of Cd doped Cu2 ZnSnS4 is dominated by donor-acceptor pairs, with carriers showing strong localization. Cd incor-poration is found to be beneficial in removing deep defects and reduce the energy shift between the emission peak and absorption edge, resulting in the reduction of the open circuit voltage loss of the solar cell device. These findings are helpful to make further improvement in device efficiency.