Magnetron Sputtered SnO<sub>2</sub> Constituting Double Electron Transport Layers for Efficient PbS Quantum Dot Solar Cells
Yong Li, Fan Yang, Yongjie Wang, Guozheng Shi, Yin Maung Maung, Jianyu Yuan, Shujuan Huang, Wanli Ma
Abstract
Herein, for the first time, it is successfully demonstrated that radio frequency (RF) magnetron sputtered SnO 2 can be a qualified alternative electron transport layer (ETL) for a high‐efficiency PbS quantum dot (QD) solar cell. The highest performing device using such a SnO 2 ETL obtains an efficiency of 8.4%, which is comparable to the sol–gel ZnO‐based one (8.8%). The excellent performance mainly results from the improved current density, which is attributed to the superior properties of the SnO 2 ETL, such as high electron mobility and excellent optical transmittance. However, it is also found that the sputtered SnO 2 ‐based devices show smaller voltage and fill factor due to the unsatisfied surface morphology and energy level alignment. By combining a thin (around 10 nm) sol–gel ZnO film on top of a sputtered SnO 2 film to form the double ETL, the best efficiency of 10.1% is obtained, which is the highest efficiency using SnO 2 ETL in a PbS QD solar cell. The work not only provides a new avenue to improve the efficiency of PbS QD solar cells but also offers the possibility to use an industry compatible sputtering technique for PbS QD solar cells.