Toward a Unified Treatment of Electronic Processes in Organic Semiconductors

A quantitative study of n-type doping in highly crystalline organic semiconductor films establishes the predominant influence of electrostatic forces in these low-dielectric materials. Based on these findings, a self-consistent model of doped (purposely or not) organic semiconductors is proposed in which: (1) the equilibrium free carrier density, nf, is a small fraction of the total charge density; (2) a superlinear increase in conductivity with doping density is universal; (3) nf increases with applied electric field; and (4) the carrier mobility is field-dependent regardless of crystallinity