Electric field and grain size dependence of Meyer-Neldel energy in C(60) films

Mujeeb Ullah; A Pivrikas; I I Fishchuk; A Kadashchuk; P Stadler; C Simbrunner; N S Sariciftci; H Sitter

doi:10.1016/j.synthmet.2011.07.008

Electric field and grain size dependence of Meyer-Neldel energy in C(60) films

Synth Met. 2011 Sep;161(17-18):1987-1990. doi: 10.1016/j.synthmet.2011.07.008.

Authors

Mujeeb Ullah¹, A Pivrikas, I I Fishchuk, A Kadashchuk, P Stadler, C Simbrunner, N S Sariciftci, H Sitter

Affiliation

¹ Institute of Semiconductor and Solid State Physics, Johannes Kepler University of Linz, A-4040 Linz, Austria.

Abstract

Meyer-Neldel rule for charge carrier mobility measured in C(60)-based organic field-effect transistors (OFETs) at different applied source drain voltages and at different morphologies of semiconducting fullerene films was systematically studied. A decrease in the Meyer-Neldel energy E(MN) from 36 meV to 32 meV was observed with changing electric field in the channel. Concomitantly a decrease from 34 meV to 21 meV was observed too by increasing the grain size and the crystallinity of the active C(60) layer in the device. These empiric findings are in agreement with the hopping-transport model for the temperature dependent charge carrier mobility in organic semiconductors with a Gaussian density of states (DOS). Experimental results along with theoretical descriptions are presented.