A Unified Distribution Form of the Density of States in Disordered Organic Semiconductors

An accurate density of states (DOS) is essential for understanding charge carrier transport properties and then better developing the electronic and optoelectronic devices. Currently, Gaussian and exponential forms are the two most general DOS, which can be unified in the tail state of the state. However, Gaussian DOS at high concentrations is not applicable, as well as exponential DOS at low concentrations. To avoid the disadvantage of Gaussian and exponential form, based on the Poisson flow, a unified distribution form of the DOS have been developed to discuss the charge carrier transport. The proposed DOS is more consistent with the actual situation and exhibits better rationality under the whole range of carrier density. Otherwise, we for the first time introduced the entropy to analyze the disorder parameters. Based on the proposed DOS, the concentration and temperature dependence of mobility has been discussed in detail.