Achieving Ultrafast Hole Transfer at the Monolayer MoS2 and CH3NH3PbI3 Perovskite Interface by Defect Engineering

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• 作者：Bo Peng ; Guannan Yu ; Yawen Zhao ; Qiang Xu ; Guichuan Xing ; Xinfeng Liu ; Deyi Fu ; Bo Liu ; Jun Rong Sherman Tan ; Wei Tang ; Haipeng Lu ; Jianliang Xie ; Longjiang Deng ; Tze Chien Sum ; Kian Ping Loh
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：June 28, 2016
• 年：2016
• 卷：10
• 期：6
• 页码：6383-6391
• 全文大小：571K
• 年卷期：0
• ISSN：1936-086X

文摘

The performance of a photovoltaic device is strongly dependent on the light harvesting properties of the absorber layer as well as the charge separation at the donor/acceptor interfaces. Atomically thin two-dimensional transition metal dichalcogenides (2-D TMDCs) exhibit strong light–matter interaction, large optical conductivity, and high electron mobility; thus they can be highly promising materials for next-generation ultrathin solar cells and optoelectronics. However, the short optical absorption path inherent in such atomically thin layers limits practical applications. A heterostructure geometry comprising 2-D TMDCs (e.g., MoS₂) and a strongly absorbing material with long electron–hole diffusion lengths such as methylammonium lead halide perovskites (CH₃NH₃PbI₃) may overcome this constraint to some extent, provided the charge transfer at the heterostructure interface is not hampered by their band offsets. Herein, we demonstrate that the intrinsic band offset at the CH₃NH₃PbI₃/MoS₂ interface can be overcome by creating sulfur vacancies in MoS₂ using a mild plasma treatment; ultrafast hole transfer from CH₃NH₃PbI₃ to MoS₂ occurs within 320 fs with 83% efficiency following photoexcitation. Importantly, our work highlights the feasibility of applying defect-engineered 2-D TMDCs as charge-extraction layers in perovskite-based optoelectronic devices.