CsPbI<sub>3</sub>/PbSe Heterostructured Nanocrystals for High-Efficiency Solar Cells
Shixun Wang, Chenghao Bi, Arsenii S. Portniagin, Jifeng Yuan, Jiajia Ning, Xufen Xiao, Xiaoyu Zhang, Yang Yang Li, Stephen V. Kershaw, Jianjun Tian, Andrey L. Rogach
Abstract
Colloidal cesium lead iodide (CsPbI3) perovskite quantum dots (QDs) are promising materials for solar cells because of their suitable optical bandgap and the ease of solution-based processing into large-area films. Herein, we report a synthetic strategy to build up a colloidal CsPbI3/PbSe heterostructure, which not only improves the absorption of sunlight but also passivates the surface of perovskite QDs, which results in a lower trap density and prolonged exciton lifetimes. Moreover, the presence of the PbSe component modifies the electronic properties of the composite films, by changing the CsPbI3 QD film from n-type to more ambipolar behavior, thus helping to promote carrier separation and collection. These improvements result in high-performance CsPbI3/PbSe QD solar cells with a power conversion efficiency of 13.9% and improved storage stability against moisture, benefiting from the hydrophobic protective coating resulting from the presence of PbSe component.