High‐Efficiency Blue Dual‐Emissive Exciplex Boosts Full‐Radiative White Electroluminescence

• Published in: Advanced optical materials 2018-10, Vol.6 (19), p.n/a
• Main Authors: Duan, Chunbo, Han, Chunmiao, Du, Ruiming, Wei, Ying, Xu, Hui
• Format: Article
• Language: English
• Subjects: Diodes; dual emission; Electroluminescence; Emissivity; exciplexes; Excitons; full radiation; Harvesting; Lighting; Materials science; Optics; Organic light emitting diodes; phosphine oxide acceptors; System effectiveness; white emission
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.201800437

Regarding lighting application, the main challenges for white organic light‐emitting diodes (WOLEDs) include the complicated structure, the high cost, and the low repeatability, which are attributed to the stringent requirement on the exciton allocation and utilization in multiradiation systems. Herein, an effective “full‐radiation white emission (FRWE)” strategy for the dynamic exciton allocation is successfully demonstrated by the first dual‐emissive blue‐emitting exciplex mCP:pTPOTZ. On the basis of an ultrasimple trilayer structure and bimaterial/trimaterial systems, its blue, yellow, and white devices realize state‐of‐the‐art performances. Especially, mCP:pTPOTZ supports its WOLEDs with ultralow driving voltages and extremely high efficiencies beyond 90 lm−1 and 24%, accompanied by a negligible roll‐off less than 10% at 1000 cd m−2. This work not only establishes a feasible method to construct dual‐emissive exciplex systems through the modulation of the donor–acceptor packing modes, but also demonstrates the superiority of FRWE strategy in 100% exciton harvesting and quenching suppression, which makes simple but high‐performance WOLED‐based lighting sources become a reality. The first dual‐emissive exciplex mCP:pTPOTZ characteristics of highly efficient blue electroluminescence with top‐rank external quantum efficiency beyond 10% are developed to demonstrate the concept of full‐radiation white emission, which endows its ultrasimple white organic light‐emitting diodes with ultralow driving voltages, state‐of‐the‐art efficiencies beyond 90 lm−1 and 24%, and a negligible roll‐off less than 10% at 1000 cd m−2.