Charge carrier mobility in sulphonated and non-sulphonated Ni phthalocyanines: experiment and quantum chemical calculations

Abstract

The objective of this interdisciplinary paper was to study theoretically and experimentally the electronic part of charge carrier transport in the class of sodium salts of sulphonated Ni phthalocyanine as candidates for p-type channels in organic field-effect transistors. These materials were selected because of their enhanced solubility as compared to their non-sulphonated counterparts. The values of the field-effect charge carrier mobility determined on the OFET structures using NiPc(SO3Na)x films were much higher than the charge carrier mobility obtained on the respective device prepared from non-substituted phthalo- cyanine. In order to explain differences between charge carrier mobility of sulphonated and non-sulphonated Ni phthalocyanines, quantum chemistry studies of molecular aggregates were performed. Quantum chem- istry modeling of the semiconductive molecular systems is new and progressive - we highlighted factors at the molecular level which led to the enhancement of the charge carrier mobility in systems containing SO3Na groups.