| he dynamics of photoexcited states in polyaniline is studied. Among the conducting polymers, polyaniline has very distinctive properties. There are three oxidation states in polyaniline. The fully reduced state leucoemeraldine base shows photoluminescence. The half oxidized emeraldine base can be reversibly protonated to become a highly conducting state emeraldine salt. The fully oxidized state pernigraniline base is, after trans-polyacetylene, the first known conjugated polymer which can accommodate neutral soliton.;In the picosecond to nanosecond time-scale photoinduced absorption measurement of pernigraniline base with pump at 2.1 eV and probe range from 1.38 eV to 1.58 eV, a hysteresis was found. Initially, only photoinduced absorption was observed. After a few minutes of optical pumping, there appeared a photoinduced bleaching at the higher energy side of the probe range. While the photoinduced absorption peak rose within the resolution of the measuring system, ;The picosecond photoinduced absorption of emeraldine base was studied. With 2.1 eV pumping, a photoinduced absorption was observed with decay time ;The photoluminescence decay time of leucoemeraldine base was measured as a function of temperature. When temperature was increased from... |
