Direct observation of photoinduced carrier blocking in mixed-dimensional 2D/3D perovskites and the origin

Dejian Yu; Fei Cao; Jinfeng Liao; Bingzhe Wang; Chenliang Su; Guichuan Xing

doi:10.1038/s41467-022-33752-5

Direct observation of photoinduced carrier blocking in mixed-dimensional 2D/3D perovskites and the origin

Nat Commun. 2022 Oct 20;13(1):6229. doi: 10.1038/s41467-022-33752-5.

Authors

Dejian Yu^{1

2}, Fei Cao^{1

2}, Jinfeng Liao², Bingzhe Wang², Chenliang Su³, Guichuan Xing⁴

Affiliations

¹ SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, China.
² Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR, 999078, China.
³ SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, China. chmsuc@szu.edu.cn.
⁴ Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macao SAR, 999078, China. gcxing@um.edu.mo.

Abstract

Mixed-dimensional 2D/3D halide perovskite solar cells promise high stability but practically deliver poor power conversion efficiency, and the 2D HP component has been held as the culprit because its intrinsic downsides (ill charge conductivity, wider bandgap, and strong exciton binding) were intuitively deemed to hinder carrier transport. Herein, we show that the 2D HP fragments, in fact, allow free migration of carriers in darkness but only block the carrier transport under illumination. While surely limiting the photovoltaic performance, such photoinduced carrier blocking effect is unexplainable by the traditional understanding above but is found to stem from the trap-filling-enhanced built-in potential of the 2D/3D HP interface. By parsing the depth-profile nanoscopic phase arrangement of the mixed-dimensional 2D/3D HP film for solar cells and revealing a photoinduced potential barrier up to several hundred meV, we further elucidate how the photoinduced carrier blocking mechanism jeopardizes the short-circuit current and fill factor.