Hot excited state management for long-lived blue phosphorescent organic light-emitting diodes

作者：Jaesang Lee, Changyeong Jeong, Thilini Batagoda, Caleb Coburn, Mark E. Thompson, Stephen R. Forrest · 发表于：Nature Communications · 年份：2017 · DOI：10.1038/ncomms15566 · 被引用次数：287 · 研究领域：Organic Light-Emitting Diodes Research、Organic Electronics and Photovoltaics、Luminescence and Fluorescent Materials

Abstract Since their introduction over 15 years ago, the operational lifetime of blue phosphorescent organic light-emitting diodes (PHOLEDs) has remained insufficient for their practical use in displays and lighting. Their short lifetime results from annihilation between high-energy excited states, producing energetically hot states (>6.0 eV) that lead to molecular dissociation. Here we introduce a strategy to avoid dissociative reactions by including a molecular hot excited state manager within the device emission layer. Hot excited states transfer to the manager and rapidly thermalize before damage is induced on the dopant or host. As a consequence, the managed blue PHOLED attains T80=334±5 h (time to 80% of the 1,000 cd m−2 initial luminance) with a chromaticity coordinate of (0.16, 0.31), corresponding to 3.6±0.1 times improvement in a lifetime compared to conventional, unmanaged devices. To our knowledge, this significant improvement results in the longest lifetime for such a blue PHOLED.