Methanol-induced luminescence vapochromism based on a Sb3+-doped organic indium halide hybrid

Ion doping has been demonstrated as a practical approach to achieving highly efficient luminescence in both inorganic phosphors and organic-inorganic hybrids. The asformed doping species show great potential in optoelectronic applications due to their high photoluminescence quantum yield (PLQY) and excellent stability. Herein, we report highly emissive Sb3+-doped indium halides (C6H18N2)InCl5 center dot H2O:Sb(C6H8N22+ = N,N,N',N'-tetramethylethane-1,2-diammonium) prepared by solution evaporation methods with an emission that peaked at 565 nm and a PLQY of 74.6%. Photophysical characterizations and density functional theory computational studies verify the broadband emission originating from a self-trapped exciton. Interestingly, a drastic red shift of the emission peak from 565 to 663 nm with yellow luminescence turning to red is observed once the (C6H18N2)InCl5 center dot H2O:Sb hybrid is exposed to methanol vapor. Moreover, when the methanol-exposed hybrid is put in air, the emission reverts to 565 nm in several minutes. Single-crystal X-ray diffraction studies show a subsequent structure distortion upon the coordination of methanol to the Sb(III) center, which is responsible for the drastic red shift of the emission. Encouragingly, we found that (C6H18N2)InCl5 center dot H2O:Sb exhibits a specific response to methanol vapor after screening a series of volatile organic compounds with different polarities. Besides, a negligible change of the emission intensity is observed after several cycles of uptaking and releasing methanol. The high fatigue resistance and specific solvent response of the Sb3+-doped indium halide make it a very promising methanol detector.

Automated summary

Ion doping is an effective method to achieve efficient luminescence in inorganic phosphors and organic-inorganic hybrids. In this study, highly emissive Sb3+-doped indium halides were synthesized and their response to methanol vapor was investigated. The doped indium halide showed specific response to methanol vapor with high fatigue resistance.