A Comprehensive study of the Effects of Chain Morphology on the Transport Properties of Amorphous Polymer Films.

Dan Mendels,Nir Tessler

doi:10.1038/srep29092

Abstract

Organic semiconductors constitute one of the main components underlying present-day paradigm shifting optoelectronic applications. Among them, polymer based semiconductors are deemed particularly favorable due to their natural compatibility with low-cost device fabrication techniques. In light of recent advances in the syntheses of these classes of materials, yielding systems exhibiting charge mobilities comparable with those found in organic crystals, a comprehensive study of their charge transport properties is presented. Among a plethora of effects arising from these systems morphological and non morphological attributes, it is shown that a favorable presence of several of these attributes, including that of rapid on-chain carrier propagation and the presence of elongated conjugation segments, can lead to an enhancement of the system’s mobility by more than 5 orders of magnitude with respect to ‘standard’ amorphous organic semiconductors. New insight for the formulation of new engineering strategies for next generation polymer based semiconductors is thus gathered.

Highlights

In the present study, to gain insight regarding the importance of chain morphology on the transport properties of amorphous polymer films, Monte Carlo transport simulations were implemented on artificially constructed films
To implement a charge transport model that stems from the Gaussian Disorder Model (GDM) framework, polymer chain segment configurations were constructed on three dimensional cubic lattices by implementing customized variations of the Slithering Snake algorithm[16,17] following a similar procedure put forward in ref
Comparing the results obtained from standard GDM simulations (X symbols) to those obtained from simulations implemented on lattice configurations (LCs) ii and iii, we find that carrier heating is suppressed due to the reduction of the system’s neighboring statistics and to greater extent the incorporation of rapid on-chain carrier propagation in the simulations (Fig. 3a)

Summary

Introduction

To gain insight regarding the importance of chain morphology on the transport properties of amorphous polymer films, Monte Carlo transport simulations were implemented on artificially constructed films. The simulations’ implementation was based on the Gaussian Disorder Model (GDM) framework given its predominant role as a modeling tool for transport in disordered organic semiconductors. This in turn allowed to carry out meaningful comparisons between the study’s findings with outputs obtained from standard implementations of the GDM framework[11,12,13,14], facilitating their discernment. Employing the GDM allowed the examination of the system over a wide range of sets of parameters In this respect the presented study can, be viewed as complementary to ab-intio studies. These tend to focus on particular material structures and their specific microscopic attributes[4,5,10,15] but by nature deal less with the effects of these attributes over ranges of parameter values

Methods

Results

Conclusion