Small Organic Molecular-Based Hybrid Halides with High Photoluminescence Quenching Temperature
Xusheng Zhang, Xingxing Jiang, Kunjie Liu, Liubing Fan, Jindong Cao, Shihui He, Na Wang, Jing Zhao, Zheshuai Lin, Quanlin Liu
Abstract
Organic–inorganic metal halides (OIMHs) exhibit excellent photoelectric properties; however, their high-temperature light-emission stability requires further improvement. Here, we report three isostructural OIMHs (C 2 H 8 N) 4 InCl 7, (C 2 H 8 N) 4 SbCl 7, and (C 2 H 8 N) 4 SbBr 7 (C 2 H 8 N + = dimethylammonium). They are all crystallized in the P 2 1 2 1 2 space group with a zero-dimensional (0D) structure, with orange-red photoluminescence (PL) under 365 nm UV excitation. Among them, (C 2 H 8 N) 4 InCl 7 exhibits the strongest PL with a photoluminescence quantum yield (PLQY) of 13.9% at room temperature. Optical property measurements and density functional theory unveil that the luminescence of (C 2 H 8 N) 4 InCl 7 at 405 and 620 nm is due to free exciton and self-trapped exciton emission, respectively. It is worth noting that (C 2 H 8 N) 4 InCl 7 shows a high PL quenching temperature, maintaining 50% of its room-temperature PL intensity at 425 K, which is rare in OIHMs. This is much higher than the application temperature of phosphors in practical solid-state lighting applications (363–383 K). In this temperature range, the luminous intensity of (C 2 H 8 N) 4 InCl 7 exceeds 60% of that at room temperature. The high PL quenching temperature observed in (C 2 H 8 N) 4 InCl 7 indicates the potential of OIMHs for applications in phosphor-converted light-emitting diodes.