1 School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China; 2 State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China; 3 Department of Materials Engineering, Lanzhou Institute of Technology, Lanzhou 730050, China
Abstract The MAPbI3 (110) surface with low indices of crystal face is a stable and highly compatible photosensitive surface. Since the electronic states on the surface can be detrimental to the photovoltaic efficiency of the device, they should be passivated. Phenylethylamine (PEA+), as a molecular ligand, has been widely used in continuous degradation and interfacial charge recombination experiments, and has satisfactory performance in improving surface defects. Therefore, we construct an adsorption model of MAPbI3 with small molecules, calculating the lattice structure and electronic properties of PEA+-adsorbed MAPbI3 (110) surface. It is found that PEA+ as a passivator can effectively weaken the electronic states and regulate the band gap of the MAPbI3 (110) surface. Before and after adding the passivator, the peak value of electronic state densities at MAPbI3 (110) surface is reduced by about 50%, and the band gap is apparently reduced. Moreover, by comparing the Bader atomic charge and spatial charge distributions before and after PEA+'s adsorption on the surface of MAPbI3, we observe a substantial change of PEA+ charges, which suggests the surface states have been passivated by PEA+.
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 11764027 and 51674130), the Scientific Research Projects of Higher Education in Gansu Province, China (Grant No. 2018A-126), and the Research Team Support Program of Lanzhou Institute of Technology (Grant Nos. 2018KW-11 and 2020KJ-01).
Wei Hu(胡伟), Ying Tian(田颖), Hong-Tao Xue(薛红涛), Wen-Sheng Li(李文生), and Fu-Ling Tang(汤富领) Passivation of PEA+ to MAPbI3 (110) surface states by first-principles calculations 2021 Chin. Phys. B 30 047101
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