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Compatible Ferroelectricity, Antiferroelectricity and Broadband Emission for a Multi-Functional 2D Organic-Inorganic Hybrid Perovskite
preprintsubmitted on 16.02.2021, 19:21 and posted on 18.02.2021, 04:33 by Wenjuan Wei, Hongqiang Gao, Yuhui Tan, Yunzhi Tang
Two-dimensional (2D) organic-inorganic hybrid perovskites with multifunctional characteristics have potential applications in many fields, such as, solar cells, microlasers and light-emitting diodes (LEDs), etc. Here, a 2D organic-inorganic lead halide perovskite, [Br(CH2)3NH3]2PbBr4 (BPA-PbBr4, BPA = Br(CH2)3NH3, 3-Bromopropylamine), is examined for its photophysical properties. Interestingly, BPA-PbBr4 reveals five successive phase transitions with decreasing temperature, including successive paraelectric-ferroelectric-antiferroelectric phases. Besides, BPA-PbBr4 displays ferroelectricity and antiferroelectricity throughout a wide temperature range (<376.4 K) with accompanying saturation polrization (Ps) values of 4.35 and 2.32 μC/cm2, respectively, and energy storage efficiency of 28.2%, and also exhibits superior second harmonic generation (SHG) with maximum value accounts for 95 % of the standard KDP due to the great deformation of structure (3.2302*10-4). In addition, the photoluminescence (PL) of the BPA-PbBr4 exhibits abnormal red-shift and blue-shift in different phases due to a consequence of competition between electron-phonon interaction and the lattice expansion. Further, BPA-PbBr4 reveals a broadband emission accompanied by bright white light at room temperature (293 K), which is supposed to be due to self-trapped excitons. In short, the versatility of BPA-PbBr4 originates from molecular reorientation of dynamic organic cations, as well as significant structural distortion of PbBr6 octahedra. This work paves an avenue to design new hybrid multifunctional perovskites for potential applications in the photoelectronic field.