The Meyer‐Neldel rule in ambipolar organic thin film transistors based on F₁₆CuPc/α6T pn heterojunction

Abstract

Abstract The temperature dependence of field‐effect mobility is investigated in ambipolar organic thin film transistors based on F 16 CuPc/α6T pn heterojunction. The results show that the thermally activated ambipolar mobilities obey the Meyer‐Neldel (MN) rule and activation energy ( E A ) steadily decreases with increasing gate voltage. At high temperatures (> 170 K), strong activated behaviour is observed, where higher E A are attributed to defects, disorder, and grain boundaries in the polycrystalline film since the transport has been described by a hopping transport process between localized trap states. Blow 170 K, much weaker activated behaviour is observed, where the charge transport is dominated by shallow traps with much lower E A . The MN energy and isokinetic temperature for both p‐channel and n‐channel are surprisingly similar to these of organic unipolar devices. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)