Photophysical Properties of Opto-Electric Molecules Studied by Time-ResolvedMicrowave Conductivity

摘要

In this thesis the photophysical properties of various donor-acceptor (DA) andsymmetrical organic compounds were investigated using the Time-Resolved Microwave Conductivity (TRMC) technique in combination with steady-state and time-resolved fluorescence techniques. On flash-photolysis of the molecules charge separated states are formed whose properties depend on aspects such as the nature of the donor and acceptor group, the length and the nature of the bridging unit, geometrical aspects such as flexibility and rotation, orbital symmetry and the dielectric properties of the bulk medium. With the TRMC technique the changes in dielectric loss, on formation of the dipolar transients can be detected with nanosecond time-resolution, by measuring the decrease in power of X-band microwaves at the resonance frequency of a cavity. If measurements are made at the half-power resonance frequencies of the cavity, additional information can be gained on the change in dielectric constant, or molecular polarizability.