Room-Temperature Luminescence Properties of p -Aminobenzoic Acid and 4-Phenylphenol Adsorbed on α-Cyclodextrin/NaCl Mixtures

The solid-surface fluorescence and phosphorescence quantum yield values and phosphorescence lifetime values were obtained for p-aminobenzoic acid (PABA) and 4-phenylphenol adsorbed on α-cyclodextrin/NaCl mixtures. From the luminescence quantum yield and phosphorescence lifetime data, the triplet formation efficiency values, the phosphorescence rate constants, and the rate constants for radiationless transition from the triplet state were determined for PABA and 4-phenylphenol on α-cyclodextrin/NaCl mixtures. In addition, the percentages of radiative and nonradiative transitions were calculated for the two compounds. The various luminescence parameters obtained in this work provided important insights into the analyte/α-cyclodextrin substrate interactions responsible for the observed solid-surface room-temperature fluorescence (RTF) and phosphorescence (RTP). Furthermore, the RTF and RTP intensities of PABA and 4-phenylphenol were obtained from several α-cyclodextrin/NaCl mixtures. These data showed the importance of the initial wet chemistry in the sample preparation procedure.