A two-dimensional Raman spectroscopic study on the structural changes of a polythiophene film during the cooling process

Raman spectra of a polythiophene film measured over a temperature range 298-98 K were analyzed using generalized two-dimensional correlation spectroscopy. In the 1600-1250 cm(-1) region, the asynchronicity of the bands indicates the existence of different species in the investigated polythiophene sample. At least four distinct bands at 1485, 1454, 1418, and 1360 cm(-1) were identified. Among them, the band at 1454 cm(-1), attributed to the neutral species of PTh, is found to be sensitive to the temperature-induced structural changes of the polythiophene film, while the bands of the oxidized species are less sensitive to the temperature change during the cooling process. (C) 2003 American Institute of Physics.