Molecular Dynamics of Poly 3-Hexyl Thiophene by Broadband Dielectric Spectroscopy

Some of the most exciting novel approaches for renewable solar energy conversion are the organic photovoltaic devices that take advantage of the unique properties of polymers such as poly(3-hexylthiphene) (P3HT). Although this type of devices present significant advantages (stability, price) their long-term performance has to be continuously improved. This study describes the dielectric behaviour of pristine poly(3- hexylthiophene) (P3HT) and its nanocomposites versus temperature and frequency by using broadband dielectric spectroscopy. Dielectric spectra reveal the existence of two relaxation phenomena (alpha, beta), below and above the glass transition. The a relaxation is related to the crystallization phenomena and the beta relaxation is due to dipolar polarization processes. These results can be incorporated into a continuous understanding of the electrical behaviours of such polymers, which play extremely important roles in the overall quality of photovoltaic devices that use such polymeric materials.