A Simplified Emissive Layer Strategy Utilizing Zero Radius of Intramolecular Energy Transfer Mechanism for High-Efficiency OLEDs

초록

A conventional exciplex emissive layer (EML) is composed of p-type and n-type hosts and dopants. Exciplex EML can enhance exciton utilization, leading to higher efficiency and operational stability. However, challenges remain in controlling the material mixing ration, maintaining uniformity during the processing steps, and addressing the high cost and the complex photophysical properties of the components. In this study, a novel 5,9-di([1,1’-biphenyl]-2-yl)-2’-(9H-carbazole-9-yl)3,7-dimethyl-5,5a,5a1,9,9a,16a-hexahydrospiro[5,9-diaza-16b-boraindeno[2,1-b]naphtho[1,2,3-fg]anthracene-11,9’-fluorene] (DABNA-Spiro-Cz), integrating a p-type host with a blue fluorescent dopant, has been designed and successfully synthesized. Within the DABNA-Spiro-Cz molecule, the p-type host and the blue fluorescent dopant are seamlessly integrated while maintaining their independent functional roles. An Exciplex is formed between the p-type host unit within the molecule and the n-type host, and the energy of the generated excitons is transferred to the dopant unit within the molecule. The successfully established zero-radius of intramolecular energy transfer in exciplex (ZETPLEX) mechanism not only simplifies the exciplex EML structure but also achieve a significantly higher external quantum efficiency (EQE) of 14.9% compared to conventional exciplex system organic light-emitting diodes (OLEDs). We present a novel pathway for high-efficiency blue OLEDs through the innovative ZETPLEX mechanism. © 2025, John Wiley and Sons Inc. All rights reserved.

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