On the Charge Carrier Time-of-Flight Mobility and the Ordering Effects in the Microcrystalline PEDOT/PSS Complex: a Morphology-Based Simulation Study

Toomas Kaevand,Jaan Kalda,Ü Lille

doi:10.5171/2013.181762

Abstract

A morphology-based method for an estimation of TOF mobility values in prototypic conjugated polymer PEDOT/PSS complex has been developed. The performed research demonstrates that the DDFT-based PEDOT density fields present the real morphology of the complex under study. The developed method enables to estimate the charge carrier mobility values in the PEDOT/PSS complex in the range of PSS/PEDOT mass ratios 1.4-20.0 reflecting anisotropy, PEDOT concentration and ordering effects.

Highlights

Charge carrier mobility is an essential complex parameter of the conjugated polymers widely used in photovoltaic devices
The performed research demonstrates that the dynamic density functional theory (DDFT)-based PEDOT density fields present the real morphology of the complex under study
The mobility calculations are typically performed using various simulations; the most popular method is (a) the Gaussian disorder model solved by Monte Carlo (MC) simulations, and its variations (Bässler, 1993, Arkhipov et al, 2002); (b) recently developed charge transfer rate calculation methods which are based on the Marcus theory, combined with real or simulated morphological models (Chatten et al, 2007),(Athanasopoulos et al, 2007)

Summary

Introduction

Charge carrier mobility is an essential complex parameter of the conjugated polymers widely used in photovoltaic devices. Poly(3,4-ethylenedioxythiophene) (abbreviated as PEDOT, in what follows referred to as T) forms a complex with counter ionic polystyrene sulfuric acid (PSS, below denoted by S) is a prototypic conjugate polymer (referred to as pristine) (Kirchmeyer and Reuter, 2005, Kim and Bredas, 2008, Groenendaal et al, 2000). It is prepared for the S/T mass ratios (RS/T) ranging from 1.4 to 20, and can be represented as consisting of T grains (domains) in the insulating S matrix (Smith et al, 2006, de Kok et al, 2004). The obtained results will hopefully show the intimate details of the electrical conductivity and the full conformity of our research of the T-S systems in the range of RS/T values between 1.4 and 20 (Kaevand et al, 2011)

Methodology

Results and Discussion

Conclusions