Performance improvement of solution-processed CdS/CdTe solar cells with a thin compact TiO_2 buffer layer  

作　　者：Aashir Waleed Qianpeng Zhang Mohammad Mahdi Tavakoli Siu-Fung Leung Leilei Gu Jin He Xiaoliang Mo Zhiyong Fan 

机构地区：[1]Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology [2]Peking University Shenzhen SOC Key Laboratory, PKUHKUST Shenzhen-Hongkong Instituition [3]Department of Materials Science, Fudan University

出　　处：《Science Bulletin》2016年第1期86-91,共6页科学通报（英文版）

基　　金：supported by Hong Kong Innovation Technology Commission project(ITS/117/13);Hong Kong Research Grants Council project(612113);Fundamental Research Project of Shenzhen Science & Technology Foundation(JCYJ20130402164725025);the International Collaboration Project of Shenzhen Science & Technology Foundation(GJHZ20130417170946221)

摘　　要：The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of Cd S window layer coating. In order to reduce the light absorption loss in Cd S, the Cd S thickness is usually less than 100 nm. However, pinholes in Cd S and non-conformal coverage of Cd S on transparent conducting oxide layer will cause shunting thus leading to device performance degradation and failure. In this paper, low-temperature and low-cost fabrication methods, i.e., chemical bath deposition and electrochemical deposition, were used to deposit Cd S and Cd Te, respectively. It was found that the yield of device was around 20 % due to shunting. In order to alleviate this problem, a compact layer of TiO2 was inserted between the fluorine-doped tin oxide and Cd S as a buffer layer. The thickness effect of TiO2 was studied and showed that devices with thin(20 nm thickness) TiO2 performed better than the counterparts with thick layers. It was discovered that device yield improved to 80 % and stability in air substantially improved with TiO2 layer.The device performance of CdS/CdTe solar cells largely depends on not only the back ohmic contact, but also the conformality of CdS window layer coating. In order to reduce the light absorption loss in CdS, the CdS thickness is usually less than 100 nm. However, pinholes in CdS and non-conformal coverage of CdS on transparent conducting oxide layer will cause shunting thus leading to device per- formance degradation and failure. In this paper, low-tem- perature and low-cost fabrication methods, i.e., chemical bath deposition and electrochemical deposition, were used to deposit CdS and CdTe, respectively. It was found that the yield of device was around 20 % due to shunting. In order to alleviate this problem, a compact layer of TiO2 was inserted between the fluorine-doped tin oxide and CdS as a buffer layer. The thickness effect of TiO2 was studied and showed that devices with thin （20 nm thickness） TiO2 performed better than the counterparts with thick layers. It was dis- covered that device yield improved to 80 % and stability in air substantially improved with TiO2 layer.

关 键 词：Thin films Titanium dioxide Solarenergy Cadmium compounds 

分 类 号：TM914.4[电气工程—电力电子与电力传动]