Modelling of the charge carrier mobility in disordered linear polymer materials

Abstract

We introduced a molecular-scale description of disordered on-chain charge carrier states into a theoretical model of the charge carrier transport in polymer semiconductors. The presented model combines the quantum mechanical approach with a semi-classical solution of the inter-chain charge hopping. Our model takes into account the significant local anisotropy of the charge carrier mobility present in linear conjugated polymers. Contrary to the models based on the effective medium approximation, our approach allowed avoiding artefacts in the calculated concentration dependence of the mobility originated in its problematic configurational averaging. Monte Carlo numerical calculations show that, depending on the degree of the energetic and structural disorder, the charge carrier mobility increases significantly with increasing charge concentration due to trap filling. At high charge carrier concentrations, the effect of the energetic disorder disappears and the mobility decreases slightly due to the lower density of unoccupied states available for the hopping transport. It could explain the experimentally observed mobility degradation in organic field-effect transistors at high gate voltage.

Impact of Hydrogen Bonds Limited Dipolar Disorder in High-k Polymer Gate Dielectric on Charge Carrier Transport in OFET

“…The small sublinear deviation observed at the high V SG limit for the OFETs with the CEPVA50 and PVPCL dielectrics could arise from the decreased density of unoccupied "fast" states available for hopping transport at very high charge concentration and relatively low energy disorder. Such dependence of the mobility on the charge concentration was also predicted in the model published by Toman et al for OFETs with P3HT active channel [49]. Although the cited model was originally developed for conjugated polymers it could be also applied for our case since the anisotropy of the charge transport, dominating along the a-axis of TIPS-P molecules, and the mobility around 0.1-0.3 cm 2 s −1 V −1 were similar.…”

“…For the latter, usually the Gaussian disorder model is used. Depending on various technical details of the solution of the transport equation several approaches may be found in the literature [45][46][47][48][49]. All these approaches consider a randomized energy disorder in the total volume.…”

Phonons spreading from laser-heated gold nanoparticle array accelerate diffusion of excitons in an underlying polythiophene thin film

“…where À x E 0.4 nm corresponds to the inter-monomer distances and N 0 E 4 (nm) À3 is the mean monomer density in P3HT, according to a very recent work of Toman, et al 39 The initial excitation density n 0 created by the pump pulse in the probed area of the sample can be calculated according to ref. 36…”

A Novel Poly-N-Epoxy Propyl Carbazole Based Memory Device

“…With increasing voltage, the charge density increased. The sharp increase in the charge mobility with the hole density due to the trap filling was directly confirmed by [ 34 ]. By further increasing the voltage, the device reached a trapped-free region after passing through the trapped-filled voltage, as shown in Figure 3 .…”