Structural Diversity in White-Light-Emitting Hybrid Lead Bromide Perovskites

• DOI: 10.1021/jacs.8b08691
• Publication Date: 2018-09-13T21:26:00Z
• Authors: Lingling Mao; Peijun Guo; Mikaël Kepenekian; Ido Hadar; Claudine Katan; Jacky Even; Richard D. Schaller; Constantinos C. S...; Mercouri G. Kanat...
• Keywords: [CHIM.MATE]Chemical Sciences/Material chemistry; 02 engineering and technology; 0210 nano-technology

Hybrid organic-inorganic halide perovskites are under intense investigations because of their astounding physical properties and promises for optoelectronics. Lead bromide chloride exhibit intrinsic white-light emission believed to arise from self-trapped excitons (STEs). Here, we report a series new structurally diverse hybrid lead that have broad-band at room temperature. They feature Pb/Br structures which vary 1D face-sharing 3D corner- edge-sharing structures. Through single-crystal X-ray diffraction low-frequency Raman spectroscopy, identified the local distortion level octahedral environments Pb2+ within The band gaps these compounds range 2.92 3.50 eV, following trend "corner-sharing < face-sharing". Density functional theory calculations suggest electronic structure is highly dependent on connectivity mode PbBr6 octahedra, where edge- corner-sharing (2,6-dmpz)3Pb2Br10 exhibits more disperse bands smaller gap (2.49 eV) than (hep)PbBr3 (3.10 eV). Using photoemission measured energies valence found them remain almost constant, while energy conduction varies. Temperature-dependent PL measurements reveal 2D narrower low temperature (∼5 K), whereas both free exciton STE emission. compound has highest photoluminescence quantum yield 12%, owing its unique allows efficient charge carrier relaxation light