Thermal effects on photogeneration of free carriers in organic conductors

We performed numerical simulations of two parallel interacting conjugated polymer chains subjected to photoionization. Within the SSH model modified to include thermal effects, an electron is removed from one chain and later absorbed by the other chain. It was obtained that the system relaxes into a free polaron in each chain. For higher electron absorption the system initially relaxes into a pair of half-polarons that spontaneously suffers monomolecular recombination. The time response of the system agrees with experimental results. Although thermal effects are important to carrier creation mechanism, the obtained photogeneration creation time is temperature independent, as suggested experimentally. (C) 2010 Elsevier B. V. All rights reserved.