Charge Transport and Electrical Properties in Poly(3-hexylthiophene) Polymer Layers

A systematic study of the charge transport and electrical properties in poly(3-hexylthiophene) (P3HT) polymer layers is performed. We demonstrate that the temperature-dependent current-voltage J(V,T) characteristics of hole−only devices based on P3HT can be accurately described using the recently introduced extended Gaussian disorder model (EGDM). A particular numerical method adopting the uneven discretization and Newton iteration method is used to solve the coupled equations describing the space-charge limited (SCL) current in conjugated polymers. For the polymer studied, we find the width of the density of states σ=0.1 eV and the lattice constant a=1.15 nm. Based on the numerical method and EGDM, we further calculate and analyze some important electrical properties for P3HT in detail, including the variation of current-voltage characteristics with the boundary carrier density and the distribution of charge-carrier density and electric field with the distance from interface.