High-Efficiency Deep-Blue Phosphor-Sensitized Fluorescent OLEDs Enabled by Cyano-Substituted Pt(II) Complexes

초록

Tetradentate Pt(II) complexes have emerged as promising phosphorescent materials for realizing deepblue organic light-emitting diodes (OLEDs) with superior performance. However, their intrinsically planar structures have enforced the attachment of complex, bulky substituents to prevent intermolecular stacking that is detrimental to their photophysical properties. In this work, we present a simple alternative strategy, namely the introduction of a cyano group. This modification suppresses emission from charge-transfer state by increasing the energy of the charge-transfer state. Utilizing the cyano-substituted Pt complex as a phosphorescent sensitizer, paired with a multi-resonance thermally activated delayed fluorescent emitter, we demonstrate a deep-blue phosphor-sensitized fluorescent (PSF) OLED achieving a maximum external quantum efficiency (EQE) > 30% and a Commission Internationale de l’Éclairage (CIE) y-coordinate below 0.1. This high-performance OLED overcomes the persistent trade-off between efficiency and color purity in the deep-blue regime, establishing a simple yet highly effective design strategy of Pt(II) complexes for advanced deep-blue OLEDs. © 2026 SPIE. All rights reserved.

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