Construction and Humidity Response of a Room-Temperature-Phosphorescent Hybrid Xerogel Based on a Multicharge Supramolecular Assembly

Organic room-temperature phosphorescence (RTP) has attracted tremendous attention in recent years due to its potential utility in combination with artificial soft materials. Herein, a room-temperature-phosphorescent hybrid xerogel held together by electrostatic and host-guest interactions is reported. The xerogel is constructed by noncovalent complexation of 7-[6-deoxy-6-(2-sulfonic)]-beta-cyclodextrin (SCD) with the phosphor bromophenyl-methyl-pyridinium chloride (PYCl) and in situ incorporation of the anionic SCD superset of PYCl complex into a cationic amino clay (AC) via electrostatic interactions. The resulting xerogel, designated AC/SCD superset of PYCl, has a network structure that can suppress vibrational and nonradiative relaxation of the phosphor, leading to green RTP emission as well as good fluorescence-phosphorescence dual emission. Notably, the intensity of the xerogel RTP varies with humidity and can be switched on and off repeatedly, which indicates that the xerogel has potential utility as an organic light-emitting humidity-sensing material.