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Self-Assembled Perovskite Nanoislands on CH3NH3PbI3 Cuboid Single Crystals by Energetic Surface Engineering |
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| Authors: | Yurou Zhang Dohyung Kim Jung-Ho Yun Jongchul Lim Min-Cherl Jung Xiaoming Wen Jan Seidel Eunyoung Choi Mu Xiao Tengfei Qiu Miaoqiang Lyu EQ Han Mehri Ghasemi Sean Lim Henry J Snaith Jae Sung Yun Lianzhou Wang |
| Affiliation: | 1. Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St. Lucia, QLD, 4027 Australia;2. Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN, 37996 USA
School of Materials Science and Engineering, University of New South Wales, Sydney, NSW, 2052 Australia;3. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU UK Graduate School of Energy Science and Technology (GEST), Chungnam National University, Daejeon, 34134 South Korea;4. Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, 305-8577 Japan;5. Centre for Translational Atomaterials, Swinburne University of Technology, Hawthorn, VIC, 3122 Australia;6. School of Materials Science and Engineering, University of New South Wales, Sydney, NSW, 2052 Australia;7. Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, NSW, 2052 Australia;8. Electron Microscope Unit, University of New South Wales, Sydney, NSW, 2052 Australia;9. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU UK |
| Abstract: | Organometal perovskite single crystals have been recognized as a promising platform for high-performance optoelectronic devices, featuring high crystallinity and stability. However, a high trap density and structural nonuniformity at the surface have been major barriers to the progress of single crystal-based optoelectronic devices. Here, the formation of a unique nanoisland structure is reported at the surface of the facet-controlled cuboid MAPbI3 (MA = CH3NH3+) single crystals through a cation interdiffusion process enabled by energetically vaporized CsI. The interdiffusion of mobile ions between the bulk and the surface is triggered by thermally activated CsI vapor, which reconstructs the surface that is rich in MA and CsI with reduced dangling bonds. Simultaneously, an array of Cs-Pb-rich nanoislands is constructed on the surface of the MAPbI3 single crystals. This newly reconstructed nanoisland surface enhances the light absorbance over 50% and increases the charge carrier mobility from 56 to 93 cm2 V?1 s?1. As confirmed by Kelvin probe force microscopy, the nanoislands form a gradient band bending that prevents recombination of excess carriers, and thus, enhances lateral carrier transport properties. This unique engineering of the single crystal surface provides a pathway towards developing high-quality perovskite single-crystal surface for optoelectronic applications. |
| Keywords: | CH 3NH 3PbI 3 nanoislands perovskite single crystals self-assembled perovskite surface engineering |
