Enhanced charge-carrier injection caused by molecular orientation

摘要

Current densities of hole-only devices based on alpha-sexithiophene (α-6T) and N-N'-diphenyl-N-N'-bis(l-naphthyl)-l ,l'-biphenyl-4,4'-diamine (α-NPD) increase 42 times at 1 V by rubbing α-6T with a Nylon cloth. Results of absorption spectroscopy with normal and oblique light incidence reveal that the rubbing induces a change from standing to lying orientations of α-6T in a film surface region. The increased current densities are attributed to enhanced α-6T-to-α-NPD hole injection due to the lying orientation.