Li掺杂对铜锌锡硫硒太阳电池的影响研究

Study on the influence of Li doping in Cu_(2)ZnSn(S_(x)Se_(1-x))_(4) solar cells

开展了基于二甲基亚砜溶剂体系的溶胶凝胶法制备铜锌锡硫硒薄膜中掺杂Li的相关研究。对不同Li掺杂量的CZTSSe薄膜分别进行了表截面形貌、晶体结构、成分比例测试,结果表明:在CZTSSe薄膜中掺杂Li可以提升薄膜的结晶质量,且随着Li掺杂量的增加,结晶质量变好。分析原因为,高温硒化过程中形成的Li_(2)Se相辅助生长改善了薄膜的结晶质量,抑制了ZnCu和SnCu等施主能级缺陷生成。但是,同样发现在Li/Cu摩尔比为1%~10%之间存在阈值,过量的Li并不能进入晶格而富集在晶界处。对不同Li掺杂的CZTSSe薄膜进行太阳电池的制备,结果表明Li/Cu为1%的太阳电池具有最高的转换效率,达到8.5%。

In this paper,the preparation of Li doped in CZTSSe films by sol-gel method based on dimethyl sulfoxide solvent system was carried out.The surface morphology,crystal structure and composition ratio of CZTSSe films with different Li doping levels were tested respectively.The results showed that the crystal quality of CZTSSe films could be improved by Li doping,and the crystal quality became better with the increase of Li doping amount.The reason is that the Li_(2)Se phase assisted growth during high temperature selenization can improve the crystal quality of the films and inhibit the formation of donor level defects such as ZnCu and SnCu.However,there is a Li doping threshold between 1%and 10%Li/Cu,and excess Li cannot enter the lattice and is enriched at the grain boundary.The results show that the solar cell with 1%Li/Cu has the highest conversion efficiency,reaching 8.5%.