Nouvelle publication de l’équipe CIEL : « Resonantly Enhanced White-Light Emission Involving Energy and Charge Transfer in One-Dimensional Hybrid Material: (ABT)2[PbBr3]«
A. Samet, S. Triki, Abid
J. Phys. Chem. C 2019 – DOI : 10.1021/acs.jpcc.9b00361
This work focus on the white light emission process occurring in a new organic-inorganic hybrid metal halide material, whith formula (C7H12N2S)2[PbBr3] abbreviated as (ABT)2[PbBr3]. Its structure consists on one-dimensional PbBr3 twin chains surrounded by 2-aminobenzothiazole (ABT) organic cations. The introduction of the optically active organic ligand (ABT) into the organic inorganic hybrid (OIH) material leads to original optical properties; indeed, under UV irradiation this material shows a white light emission with an impressive intensity that can be seen even with naked eye. Pholuminescence (PL) spectrum is characterized by a large emission band covering a wide range of the visible spectrum and composed by bleu, green, yellow and red components around 450 nm, 475 nm, 530 nm and 580 nm respectively. The PL measurements with vaious excitations shows that white light emission occurs only in a norrow resonant excitation range around 3.14 eV (394nm). PLE investigation and DFT band structure calculation revealed that this resonant excitation range corresponds to the coincidence of an intrinsec distribution of self trapet states in the inorganic PbBr3 distorted chain, with the frontier molecular orbitals of the organic cation. In addition, such an interaction between two ionic chromophores placed at very close distances is beleaved to be accompanied by a Dexter charge / energy transfert.sion model becomes very relevant and leads to an excellent agreement with the experimental observations.