Circularly Polarized Luminescence Optical Waveguides Based on One-Dimensional Hybrid Copper-Silver Bromide Crystal

Chiroptical waveguides, capable of generating and propagating circularly polarized light (CPL), hold significant promise for next-generation optoelectronic devices. However, developing novel, efficient chiroptical waveguides remains challenging, due to the difficulty of integrating strong intrinsic chiroptical activity with efficient directional light transport within a single crystalline material. Here, we report a new enantiomeric pair of chiral hybrid metal halides, (S/R-C₅H₁₄N₂)CuAgBr₄ (S/R-CuAg), featuring a one-dimensional inorganic structure. Ag incorporation enhances photoluminescence quantum yield from 0.6% to 18.6%, while enabling bright CPL emissions with dissymmetry factors (g_lum) of ± 7 × 10^-3. The tightly packed inorganic lattice and highly anisotropic microstructure of S/R-CuAg exhibit a low optical loss coefficient of 9.6 × 10^-3 dB µm^-1. Crucially, microrod crystals of S/R-CuAg function as efficient chiroptical waveguides, simultaneously emitting and propagating CPL under unpolarized light excitation. This work establishes chiral hybrid metal halides as a viable platform for circularly polarized waveguide applications.