Zero-Dimensional Tellurium-Based Organic-Inorganic Hybrid Halide Single Crystal with Yellow-Orange Emission from Self-Trapped Excitons

Organic-inorganic hybrid halides and their analogs that exhibit efficient broadband emission from self-trapped excitons (STEs) offers an unique pathway towards realization of highly efficient white light sources for lighting applications. An appropriate dilution of ns² ions into a halide host is essential to produce auxiliary emissions. However, the realization of ns² cation-based halides phosphor that can be excited by blue light-emitting diode (LED) is still rarely reported. In this study, a zero-dimensional Te-based single crystal (C₈H₂₀N)₂TeCl₆ was synthesized, which exhibits a yellow-orange emission centered at 600 nm with a full width at half maximum of 130 nm upon excitation under 437 nm. Intense electron-phonon coupling was confirmed in the (C₈H₂₀N)₂TeCl₆ single crystal and the light emitting mechanism is comprehensively discussed. The results of this study are pertinent to the emissive mechanism of Te-based hybrid halides and can facilitate discovery of unidentified metal halides with broadband excitation features.