Light‐Emitting Metal–Organic Halide 1D and 2D Structures: Near‐Unity Quantum Efficiency, Low‐Loss Optical Waveguide and Highly Polarized Emission

Organic-inorganic metal-halide materials (OIMMs) with zero-dimensional (0D) structures offer useful optical properties with a wide range of applications. However, successful examples of 0D structural OIMMs with well-defined optical performance at the micro-/nanometer scale are limited. We prepared one-dimensional (1D) (DTA)₂ SbCl₅ ⋅DTAC (DTAC=dodecyl trimethyl ammonium chloride) single-crystal microrods and 2D microplates with a 0D structure in which individual (SbCl₅ )^2- quadrangular units are completely isolated and surrounded by the organic cation DTA⁺ . The organic molecular unit with a long alkyl chain (C₁₂ ) and three methyl groups enables microrod and -plate formation. The single-crystal microrods/-plates exhibit a broadband orange emission peak at 610 nm with a photoluminescence quantum yield (PLQY) of ca. 90 % and a large Stokes shift of 260 nm under photoexcitation. The broad emission originates from self-trapping excitons. Spatially resolved PL spectra confirm that these microrods exhibit an optical waveguide effect with a low loss coefficient (0.0019 dB μm^-1 ) during propagation, and linear polarized photoemission with a polarization contrast (0.57).