Afterglow Light-Emitting Diodes Incorporating Bright Closely Stacked Molecular Dimers with Ultra-Long Thermally Activated Delayed Fluorescence

• DOI: 10.2139/ssrn.4255220
• Publication Date: 2022-11-04T20:36:19Z
• Authors: Weidong Qiu; Denghui Liu; Zijian Chen; Yiyang Gan; Shu Xiao; Xiaomei Peng; Difei Zhang; Xinyi Cai; Mengke Li; Wentao Xie; Guanwei Sun; Yihang Jiao; Qing Gu; Dongge Ma; Shi-Jian Su

Purely organic luminescent materials exhibiting afterglow emission after photoexcitation have been developed recently and hold great promise for future applications, while the from electroexcitation remains rare inefficient. Here, electroluminescence was achieved based on an dimer system with high photoluminescence quantum yield unprecedented long-lived thermally activated delayed fluorescence (TADF) characters. The strong π-π interactions aggregation structures can suppress nonradiative transition promote emission. In addition, molecular stacking also renders a moderate singlet-triplet energy gap, enabling TADF afterglow. As result, observed in light-emitting diodes (OLEDs) system, external efficiency of 14.7% lifetime 157 ms. This work not only extends scope purely aggregates novel optoelectronic properties applications but opens up new pathways achieving efficient OLEDs mechanism.