Mobility-Dependent Charge-Transfer Efficiency at the ZnO/MAPbI<inf>3</inf> Perovskite Contact: Developing a Novel Test Platform for Probing Electrical Contact Properties

Abstract

Organic-inorganic hybrid perovskites have attracted much attention since the demonstration of a facile formation of functional interfaces in combination with metal oxides in energy and display applications. We report a direct study in which interfacial charge-transfer efficiency at the methylammonium lead iodide (MAPbI3) perovskite/zinc oxide (ZnO) interface is quantified through measurement of the net injection current. Electrical contact and MAPbI3 perovskite channel properties were separately extracted through a novel ZnO/MAPbI3 perovskite/ZnO field-effect transistor test platform device in which highly conductive (0.014 ω cm) ZnO electrodes were used as source and drain electrodes. Through simultaneous probing of the contact and the channel properties, we, for the first time, found that charge-transfer efficiency at the ZnO/MAPbI3 contact is dependent on MAPbI3 perovskite mobility and charge-transport properties in the MAPbI3 channel region extend to the ZnO/MAPbI3 interface influencing the charge-injection efficiency. A comprehensive study of the interfacial charge transfer associated with charge-transport and charge-injection barrier is provided through a discussion of a theoretical charge-injection model in which the net current is determined as a result of the competition between the injection current and the surface recombination current. © 2019 American Chemical Society.