OPTICAL STUDIES OF REGIOREGULAR POLY(3-OCTYLTHIOPHENE)S UNDER PRESSURE

Regioregular poly(3-octylthiophenl) was subjected to optical spectrosc opy studies. Spectra were collected for different values of external, hydrostatic pressure. A decrease of optical gap is observed due to dec rease of the torsion angle between the adjacent thiophene ring and the enhancement of interchain interactions between parallel polymer plane s. Measurements were performed for pressure up to 0.5 GPa at room temp erature. The presented spectra are compared with those for non-regiore gular poly(3-octylthiophene). Better resolution of the fine structure of the spectrum and lower optical energy Eap are rationalized as the e ffect of a higher level of crystallinity and better planarity of the r egioregular system. (C) 1998 Elsevier Science S.A. All rights reserved .