Structural inhomogeneity of non-regioregular poly(3-hexylthiophene) in a solution and solid films structures and electronic properties

We study structures and electronic properties of non-regioregular poly(3-hexylthiophene) (P3HT) in a chloroform solution and in solid films prepared under various conditions. The extent of conjugation seems to be inhomogeneous for a slowly dried cast film. However, a rather uniform extent of conjugation is suggested for a spin-coated film. In photoluminescence excitation (PLE) spectra probed at 710 nm, large differences are found between these spin-coated and cast films. Based on structural features, exciton behavior is discussed.