Near-infrared and visible dual-band circularly polarized luminescence from chiral hybrid indium halides co-doped with Yb3+ and Sb3+
摘要
Chiral organic-inorganic hybrid metal halides (OIHMHs) have emerged as multifunctional materials with remarkable structural diversity and chiroptical properties. Despite significant progress, current chiral OIHMHs predominantly exhibit circularly polarized luminescence (CPL) in the visible spectrum, whereas achieving ultraviolet and near-infrared (NIR) CPL remains challenging. Herein, we report a series of lead-free chiral zero-dimensional (0D) OIHMHs, (R/S-DACH)2In2Br10:Sb3+/Yb3+ (DACH = 1,2-diaminocyclohexane), featuring spectrally tunable CPL emissions covering the visible to NIR regions. Single-crystal X-ray diffraction analysis combined with circular dichroism and CPL spectroscopy revealed that robust hydrogen-bonding interactions between organic cations and inorganic emitters in the structure play a crucial role in the chirality expression of the hybrid halides. The Sb3+-doped (R/S-DACH)2In2Br10 single crystals (SCs) exhibited intense broadband emission at 644 nm, originating from the radiative transition of Sb3+ ions from 3P1 to 1S0. This emission achieved a record photoluminescence quantum yield of 49.9% (two orders of magnitude higher than that of pristine crystals) and a luminescence dissymmetry factor (glum) of ±7.1×10−3. Notably, Sb3+/Yb3+ co-doped (R/S-DACH)2In2Br10 SCs simultaneously generated dual-band CPL emissions at 644 nm (glum = ±2.1×10−2) and 994 nm (glum = ±6.8×10−3), representing an important example of NIR-CPL activity realized in OIHMHs. The fabricated LED device based on (R-DACH)2In2Br10:2.7%Sb3+ SCs exhibited bright orange emission with a color-rendering index of 78.4, along with excellent spectral and operational stabilities. These findings not only establish a unique design strategy for tailoring broadband CPL but also expand the application potential of chiral metal halides in advanced optoelectronic technologies.