Estimation of Energetic and Charge Transfer Properties of Iridium(III) Bis(2-phenylpyridinato-<italic>N,C</italic>2’)acetylacetonate by Electrochemical Methods

Abstract

Iridium(III) bis(2-phenylpyridinato-N,C 2 ')acetylacetonate ((ppy) 2 Ir(acac)), a green dopant used in organic light-emitting devices (OLEDs), was subjected to electrochemical characterization to estimate its formal oxidation potential (E o '), HOMO energy level (E H O M O), electron transfer rate constant (k o '), and diffusion coefficient (D o). The employed combination of voltammetric methods, i.e., cyclic voltammetry (CV), chronocoulometry (CC), and the Nicholson method, provided meaningful insights into the electron transfer kinetics of (ppy) 2 Ir(acac), allowing the determination of k o ' and D o. The quasireversible oxidation of (ppy) 2 Ir(acac) furnished information on E o ' and E H O M O , allowing the latter parameter to be easily estimated by electrochemical methods without relying on expensive and complex ultraviolet photoemission spectroscopic (UPS) measurements.