P‐208: Phosphorescent Sensitizer Design for DET Suppression and Energy Transfer Analysis

Phosphor‐sensitized fluorescence (PSF) is a well‐established approach for optimizing the efficiency, lifetime, and color purity of organic light‐emitting diodes (OLEDs). To fully utilize PSF system, it is crucial to suppress Dexter energy transfer (DET) and quantify its occurrence. In this study, we synthesized a novel platinum complex, Pt‐BPS, incorporating bulky functional groups to PtON7‐dtb reference molecule to minimize DET. We also developed an integrated energy transfer model to accurately quantify the rate constants of Förster resonance energy transfer (FRET) and DET using Monte Carlo simulations. Based on these findings, we fabricated PSF OLED devices using PtON7‐dtb and Pt‐BPS and the Pt‐BPS‐based PSF OLEDs demonstrated a significantly improved maximum external quantum efficiency (EQEmax) compared to PtON7‐dtb PSF OLEDs. This research provides key insights into the design strategy of phosphor sensitizer for DET suppression in PSF systems, offering a deeper understanding of FRET and DET rate constants through an integrated energy transfer model.