Detailed analysis of charge transport in amorphous organic thin layer by multiscale simulation without any adjustable parameters

Abstract

Hopping-type charge transport in an amorphous thin layer composed of organic molecules is simulated by the combined use of molecular dynamics, quantum chemical, and Monte Carlo calculations. By explicitly considering the molecular structure and the disordered intermolecular packing, we reasonably reproduce the experimental hole and electron mobilities and their applied electric field dependence (Poole–Frenkel behaviour) without using any adjustable parameters. We find that the distribution of the density-of-states originating from the amorphous nature has a significant impact on both the mobilities and Poole–Frenkel behaviour. Detailed analysis is also provided to reveal the molecular-level origin of the charge transport, including the origin of Poole–Frenkel behaviour.

Theoretical modeling of charge transport in triphenylamine–benzimidazole based organic solids for their application as host-materials in phosphorescent OLEDs

“…Commonly site energy differences are inuenced by applied electric eld, electrostatic interaction and polarization. In this work, the charge transfer rate is tuned by site energy gap with the help of applied electric eld, [27][28][29] where, E i , and E j are site energies of i th and j th molecule, and e,Ẽ andR ij are electronic charge (1.6 Â 10 À19 C), applied electric eld and intermolecular distance (3.5Å), respectively. In this model, we assume the variation of site-energy gap (due to applied eld) as 0, 0.025, 0.05, 0.075 and 0.1 eV, in this charge transport calculation.…”

Effect of Coulomb correlation on charge transport in disordered organic semiconductors

“…Assuming incoherent hopping of charge carriers between localized states and using advanced three-dimensional (3D) mechanistic modeling techniques, it is now possible to predict the macroscopic charge transport properties of organic semiconductors using microscopic information at the molecular level, including a Gaussian distribution of site energies, the spatial packing of the material, the distribution of charge transfer integrals, and the reorganization energies [5][6][7][8][9][10][11][12]. Device modeling has been carried out using drift-diffusion [13][14][15][16][17][18], master-equation (ME) [19][20][21][22][23], and kinetic Monte Carlo (KMC) [2,[24][25][26][27][28] simulation methods.…”

The researcher's guide to solid-state dye-sensitized solar cells

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