ABSTRACT The operational stability of blue phosphorescent organic light‐emitting diodes (PHOLEDs) remains the most significant barrier to their comprehensive commercialization. In this work, we propose a unified analytical framework that synergistically bridges the gap between intrinsic material properties and complex device‐level degradation. By integrating transient photoluminescence (TrPL), which probes the fundamental photophysical kinetics of materials, with magneto‐electroluminescence (MEL), which diagnoses exciton dynamics under actual electrical operation, we provide a holistic understanding of the degradation landscape. Through TrPL, we quantitatively evaluate host‐ and exciplex‐mediated exciton recycling rates (ERRs), establishing how specific material architectures govern triplet harvesting efficiency. This material‐level insight is then cross‐correlated with MEL analysis, which uncovers in situ exciton‐conversion mechanisms—such as hyperfine‐driven ISC and Δg‐induced rISC suppression—and identifies the impact of high‐field bimolecular interactions on device longevity. Our findings demonstrate that this dual‐approach overcomes the limitations of conventional single‐method characterization, offering an unprecedented view of how molecular‐level recycling channels translate into macroscopic device stability. This unified framework serves as a high‐value diagnostic tool for OLED degradation research and provides definitive strategic guidelines for the molecular engineering and architectural design of high‐stability, next‐generation blue OLEDs.
Lee et al. (2026) studied this question.