Charge transport through polymer thin films for second order nonlinear optics

Abstract

Charge transport through molecularly doped polymer thin films for second order nonlinear optical applications has been investigated using Monte Carlo simulations. By implementing disorder into the molecular energetics to approximate the polymer properties, a simulation has been developed to calculate time of flight current transients. The dopant molecules, nonlinear optically active chromophores, are modeled as individual sites with a discrete energy spectra, while the monomer units of the polymer matrix are modeled as individual sites with energies described by a single gaussian distribution. Parameters such as temperature, magnitude of the applied electric field, and chromophore concentration are used in the simulation to predict physically realistic processing conditions. Other important parameters include the size and shape of the dopant chromophores, the polarity and polarization effects of both the polymer and chromophore, and the intermolecular interaction between the chromophore and polymer molecules. Dielectric relaxation and isothermal current decay measurements are being used to experimentally determine the magnitude of the intermolecular interactions. The characterization of charge transport properties is crucial to the development of any potential second order nonlinear optical device.