Promising Cd-free double buffer layer in CZTSSe thin film solar cells  

铜锌锡硫硒薄膜太阳电池中有希望的无镉双缓层

作　　者：Siyu Wang Zhenwu Jiang Zhan Shen Yali Sun Hongling Guo Li Wu Jianjun Zhang Jianping Ao Hai Wang Yi Zhang 王思宇;姜振武;申展;孙亚利;郭洪玲;武莉;张建军;敖建平;王海;张毅(Institute of Photoelectronic Thin Film Devices and Technology,Tianjin Key Laboratory of Thin Film Devices and Technology,Nankai University,Tianjin,300350,China;The Key Laboratory of Weak-Light Nonlinear Photonics,Ministry of Education,School of Physics,Nankai University,Tianjin,300071,China;College of Electronic Information and Optical Engineering,Nankai University,Tianjin,300350,China)

机构地区：[1]Institute of Photoelectronic Thin Film Devices and Technology,Tianjin Key Laboratory of Thin Film Devices and Technology,Nankai University,Tianjin,300350,China [2]The Key Laboratory of Weak-Light Nonlinear Photonics,Ministry of Education,School of Physics,Nankai University,Tianjin,300071,China [3]College of Electronic Information and Optical Engineering,Nankai University,Tianjin,300350,China

出　　处：《Science China Materials》2021年第2期288-295,共8页中国科学（材料科学（英文版）

基　　金：the National Key R&D Program of China(2019YFB1503500,2018YFE0203400 and2018YFB1500200);the National Natural Science Foundation of China(U1902218 and 11774187);the 111 Project(B16027)。

摘　　要：Zn(O,S)film is widely used as a Cd-free buffer layer for kesterite thin film solar cells due to its low-cost and eco-friendly characteristics.However,the low carrier concentration and conductivity of Zn(O,S)will deteriorate the device performance.In this work,an additional buffer layer of In2S3 is introduced to modify the properties of the Zn(O,S)layer as well as the CZTSSe layer via a post-annealing treatment.The carrier concentrations of both the Zn(O,S)and CZTSSe layers are increased,which facilitates the carrier separation and increases the open circuit voltage(VOC).It is also found that ammonia etching treatment can remove the contamination and reduce the interface defects,and there is an increase of the surface roughness of the In2S3 layer,which works as an antireflection layer.Consequently,the efficiency of the CZTSSe solar cells is improved by 24%after the annealing and etching treatments.Simulation and experimental results show that a large band offset of the In2S3 layer and defect energy levels in the Zn(O,S)layer are the main properties limiting the fill factor and efficiency of these CZTSSe devices.This study affords a new perspective for the carrier concentration enhancement of the absorber and buffer layers by In-doping,and it also indicates that In2S3/Zn(O,S)is a promising Cd-free hybrid buffer layer for high-efficiency kesterite solar cells.Zn(O,S)薄膜由于低成本和生态友好的特性而被广泛用作锌黄锡矿薄膜太阳能电池的无镉缓冲层.但是Zn(O,S)缓冲层的载流子浓度和电导率较低,这将会导致器件性能的降低.在这项工作中,我们引入了一层额外的In2S3缓冲层,并通过后退火处理来改进Zn(O,S)层以及CZTSSe层的属性.经过退火处理后,我们发现Zn(O,S)和CZTSSe层的载流子浓度均增加,这有助于载流子分离并增加开路电压.此外还发现,氨水蚀刻处理可以去除污染物,减少界面缺陷,并且增加In2S3层的表面粗糙度以用作减反层.因此,经过退火和蚀刻处理后,CZTSSe太阳能电池的效率提高了24%.仿真和实验结果表明,In2S3层和Zn(O,S)层中的缺陷能级之间较大的能带偏移是限制CZTSSe器件的填充因子和效率的主要原因.以上研究表明In2S3/Zn(O,S)是一种有希望的高效锌黄锡矿太阳能电池的无镉双缓冲层.本研究还为通过铟掺杂提高吸收层和缓冲层的载流子浓度提供了新的视角.

关 键 词：double buffer layer CZTSSe In-doping band offset 

分 类 号：TM914.4[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]