Annealing effects on interfacial electronic structures and photoexcitation kinetics of regioregular poly(3-hexylthiophene) film on gold

The authors have studied annealing effects on the interfacial electronic structures and long-lived photoexcitation kinetics of poly(3-hexylthiophene-2,5-diyl) (P3HT) on gold, in comparison with poly[2-methoxy-5-(2(')-ethyl-hexyloxy)-1,4-phenylene vinylene], using two-photon photoemission spectroscopy. Their studies show dramatic annealing effects on the two-photon photoemission yield and the kinetics of long-lived photoexcitations of P3HT. The interfacial electronic structures also strongly depend on the thermal annealing condition. Upon annealing P3HT, the photoemission yield is enhanced by two orders of magnitude, and the work function decreases by 1.0 eV. (c) 2007 American Institute of Physics.