Phosphorescence of Adsorbed Ionic Organic Molecules at Room Temperature

Many salts of polynuclear carboxylic acids, phenols, amines, and sulfonic acids adsorbed on paper, silica, alumina, and other substrates exhibit strong triplet phosphorescence at room temperature, with no evidence of quenching by oxygen. No phosphorescence has been observed with nonionic materials. The spectra are similar to those of frozen solutions at -196 degrees C, and the technique provides a simple means of demonstrating phosphorescence phenomena, identifying unknown materials, and investigating the spectra of triplet states.