Random and multipath transport model for organic semiconductors

Abstract An analytical random and multipath transport (RMT) model for ordered organic semiconductors ‌is developed based on the microscopic definition of mobility, the Miller-Abraham hopping rate, ‌and the‌ central limit theorem (CLT). The RMT model ‌can take‌ main factors affecting mobility in organic semiconductors into account, including temperature, density, electric field, density of states (DOS), ‌and‌ structure. The numerical results for Gaussian DOS ‌regarding‌ the relationship between mobility and density ‌show good agreement with‌ simulation results ‌reported in the literature‌ under a fixed ratio ‌between‌ localization length ‌and‌ nearest-neighbor distance. ‌Comparisons of‌ results for different structures ‌reveal no significant influence‌ on mobility. The RMT model well describes‌ mobility in disordered systems ‌through‌ slight adjustment of the DOS width parameter ‌representing‌ energy disorder. The estimated contribution of structural disorder to mobility is less than ‌10% as compared with that of‌ energy disorder.