Affiliation:
1. Institute of Applied Physics and Materials Engineering University of Macau Macau China
2. MOE Key Laboratory for Non‐equilibrium Synthesis and Modulation of Condensed Matter, State Key Laboratory for Mechanical Behavior of Materials, School of Physics Xi'an Jiaotong University Xi'an China
3. Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai China
4. Department of Materials Science and Engineering & Center of Super‐Diamond and Advanced Films City University of Hong Kong Hong Kong China
Abstract
Two‐dimensional materials have been widely used to tune the growth and energy‐level alignment of perovskites. However, their incomplete passivation and chaotic usage amounts are not conducive to the preparation of high‐quality perovskite films. Herein, we succeeded in obtaining higher‐quality CsPbBr3 films by introducing large‐area monolayer graphene as a stable physical overlay on top of TiO2 substrates. Benefiting from the inert and atomic smooth graphene surface, the CsPbBr3 film grown on top by the van der Waal epitaxy has higher crystallinity, improved (100) orientation, and an average domain size of up to 1.22 μm. Meanwhile, a strong downward band bending is observed at the graphene/perovskite interface, improving the electron extraction to the electron transport layers (ETL). As a result, perovskite film grown on graphene has lower photoluminescence (PL) intensity, shorter carrier lifetime, and fewer defects. Finally, a photovoltaic device based on epitaxy CsPbBr3 film is fabricated, exhibiting power conversion efficiency (PCE) of up to 10.64% and stability over 2000 h in the air.
Funder
City University of Hong Kong
Fundo para o Desenvolvimento das Ciências e da Tecnologia
Subject
Energy (miscellaneous),Waste Management and Disposal,Environmental Science (miscellaneous),Water Science and Technology,General Materials Science,Renewable Energy, Sustainability and the Environment