General Approach To Compute Phosphorescent OLED Efficiency

TL;DR

This paper introduces a comprehensive computational method combining quantum chemistry and kinetic modeling to accurately predict the photoluminescence lifetimes and efficiencies of Ir(III) complexes in phosphorescent OLEDs, aiding in emitter design.

Contribution

It presents a novel, general computational approach that explicitly includes temperature-dependent deactivation processes for predicting OLED emitter efficiencies.

Findings

Effective for a broad range of Ir(III) complexes from yellow to deep-blue.

Accurately predicts photoluminescence lifetimes and efficiencies.

Provides a reliable tool for designing new phosphorescent emitters.

Abstract

Phosphorescent organic light-emitting diodes (PhOLEDs) are widely used in the display industry. In PhOLEDs, cyclometalated Ir(III) complexes are the most widespread triplet emitter dopants to attain red, e.g., Ir(piq)3 (piq = 1-phenylisoquinoline), and green, e.g., Ir(ppy)3 (ppy = 2-phenylpyridine), emissions, whereas obtaining operative deep-blue emitters is still one of the major challenges. When designing new emitters, two main characteristics besides colors should be targeted: high photostability and large photoluminescence efficiencies. To date, these are very often optimized experimentally in a trial-and-error manner. Instead, accurate predictive tools would be highly desirable. In this contribution, we present a general approach for computing the photoluminescence lifetimes and efficiencies of Ir(III) complexes by considering all possible competing excited-state deactivation processes and importantly explicitly including the strongly temperature-dependent ones. This approach is based on the combination of state-of-the-art quantum chemical calculations and excited-state decay rate formalism with kinetic modeling, which is shown to be an efficient and reliable approach for a broad palette of Ir(III) complexes, i.e., from yellow/orange to deep-blue emitters.