Low energy neutral and charged excitations in α-sexithienyl: a polythiophene model compound

Abstract

Photoluminescence and photoconductivity action spectra of α-sexithienyl (T₆) are reported and discussed. The photoluminescence spectrum of oriented sublimed thin film of T₆ at 4.2 K shows a one to one correspondence with similar spectra of good crystalline quality of chemically synthesized polythiophene (PT). The photoconductivity action spectrum of T₆ is complementary to the luminescence excitation spectrum indicating that the electron-hole pair creation is the dominant channel of non radiative decay for excitation higher than the bottom of the lowest B_u excitonic band. We suggest T₆ as a good model compound for PT.