电沉积法制备铜锌锡硫薄膜太阳能电池吸收层的研究进展

Research Progress on Absorber Layers of Cu_2ZnSnS_4(CZTS)Thin Film Solar Cell Prepared by Electrodeposition

直接禁带半导体材料铜锌锡硫(CZTS)四元硫化物是近年来研究较多的具有锌黄锡矿结构的化合物半导体,由于其光吸收系数较高,禁带宽度适中,是太阳能电池理想的候选材料,使其在薄膜太阳能电池中迅速崛起。由于目前报道的最高转换效率距离其理论转换效率还存在相当差距,因此,研究CZTS(Se)四元硫(硒)化物半导体仍然是当前的研究热点之一。简单介绍了CZTS薄膜太阳能电池的结构组成,并详细介绍了3种主要制备CZTS薄膜的电沉积方法,即分步沉积Cu/Sn/Zn金属层、连续沉积Cu-Zn-Sn金属层、一步沉积Cu-Zn-Sn-S(Se)制备CZTS薄膜太阳能电池吸收层的电化学技术及相应器件,对其研究进展进行了综述,指出了相应方法存在的问题。还将3种电沉积方法进行了分析比较,提出了优化方法,展望了未来的发展趋势。

Cu2ZnSnS4 （CZTS）, a quaternary chalcogenide-based compound semiconductor, has attracted much interest in applications on absorber layers of thin film solar cells, due to its direct band-gap, high optical absorption coefficient, and medium band gap matched solar spectrum. There remains huge gaps between the current reported the highest conversion efficiency and the theoretical power conversion efficiency, which drive scientists and researchers to improve the efficiencies through thin film synthesizing methods. Among various methods to synthesize CZTS thin films, electrodepositon is of particular interest due to low cost, environmental friendly, large area deposition and room temperature growth. After briefly introduces the structure of CZTS thin film solar cells, this paper reviews three electrodeposition approaches to obtain kesterite precursors including： （a） sequential electrodeposition of metallic stacked layers on Cu, Sn and Zn, （b） simultaneous electrodeposition of metallic Cu, Zn, and Sn, and （c） quaternary or chalcogenide electrodeposition,Cu-Zn-Sn-S（Se）. Meanwhile, the preparation of CZTS thin film solar cell absorption layer by those three kinds of electrochemical techniques and the progress in the corresponding device performance have been also discussed, and the existing problems correspond to each method are pointed out. Finally, three kinds of electrodeposition methods are analyzed and compared, optimization method and the trend of future development are proposed.