DETERMINATION OF THERMAL PARAMETERS AND THE OPTICAL GAP OF POLY(3-BUTYLTHIOPHENE) FILMS BY PHOTOPYROELECTRIC SPECTROSCOPY

Thermal parameters and the optical gap of undoped poly(3-butylthiophene) films were determined by photopyroelectric spectroscopy, using a PVDF film as the pyroelectric detector. The band gap energy was determined using both the amplitude and the phase curves for different chopping frequencies. When the theoretical model developed by Mandelis and Zver [J. Appl. Phys. 57, 4421 (1985)], was applied to the experimental results comprising amplitude and phase difference spectra, the thermal diffusivity and the thermal conductivity were obtained as fitting parameters.