AUTHOR=Ozu Shuhei , Zhang Yaohong , Yasuda Hironobu , Kitabatake Yukiko , Toyoda Taro , Hirata Masayuki , Yoshino Kenji , Katayama Kenji , Hayase Shuzi , Wang Ruixiang , Shen Qing 

TITLE=Improving Photovoltaic Performance of ZnO Nanowires Based Colloidal Quantum Dot Solar Cells via SnO2 Passivation Strategy

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 7 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2019.00011

DOI=10.3389/fenrg.2019.00011

ISSN=2296-598X

ABSTRACT=Colloidal quantum dot solar cells (CQDSCs) based on one-dimensional metal oxide nanowires (NWs) as electron transport layer (ETL) have attracted much attention due to its larger ETL/colloidal quantum dots (CQDs) contact area and longer electron transport length than other structure CQDSCs, such as planar CQDSCs. However, it is known that defect states in NWs would increase the recombination rate because of the high surface area of NWs. Here, the defect species on the ZnO NWs surface which resulted in the surface recombination and SnO2 passivation effects were investigated. Comparing with the solar cells using pristine ZnO NWs, the CQDSCs which based on SnO2 passivated ZnO NWs electrode exhibited a beneficial band alignment to charge separation, and the interfacial recombination at ZnO/CQDs interface was reduced, eventually resulted in a 40% improvement of power conversion efficiency (PCE). Overall, these findings indicate that surface passivation and the reduction of deep level defect in ETLs could contribute to improve the PCE of CQDSCs.