The Delayed Fluorescence of Indole in Alcohol-Alkane Mixed Glasses at 77 K

Abstract

Abstract Using a phosphoroscope and a pulsed light-signal integrator, the effect of alcohol on the delayed fluorescence of indole was investigated in alcohol-isopentane mixed glasses at 77 K. The delayed fluorescence intensity was strongly depended on the alcohol concen-tration and the polarity of alcohol. Trapped electrons causing the delayed fluorescence were separated into two species utilizing the scavenge effect of CCl4; shallow trapped-electrons sensitive to CCl4 and deep trapped-electrons insensitive to CCl4. The former electrons seem to be responsible for the delayed fluorescence at low alcohol concentrations, whereas the latter for the delayed fluorescence at higher alcohol concentrations. The delayed fluorescence decayed exponentially at low alcohol concentrations, but it decayed with the Debye-Edwards law of t-1 at higher alcohol concentrations. The recombination mechanism of trapped electrons with parent cations was discussed. The structure of shallow traps was also estimated.