Structural and photo-physical properties of spin-coated poly(3-hexylthiophene) thin films

Regioregular poly(3-hexylthiophenes) (P3HTs) and its blends were studied regarding their structural and photo-physical properties using fullerene as an electron acceptor material. Photo-physical and structural characteristics of the polymer blends were studied using UV–vis spectroscopy, photoluminescence (PL), Fourier transform infrared absorption (FTIR) spectroscopy and Raman spectroscopy analysis. Films based on the polymer blends with C60 showed photo-induced absorption characteristic for charged excitations. The absorption spectra of the rr-P3HT exhibit a shift to higher energies (blue shift) of the π–π* inter-band transition upon mixing with C60. A distinctive photoluminescence quenching effect is observed indicating photo-induced electron transfer. The complete reduction of PL of P3HT after mixing with C60 in a 1:1 weight ratio indicates an effective charge transfer from P3HT to C60.