High-performance nondoped organic light-emitting diodes(OLEDs)are promising technologies for future commercial applications.Herein,we synthesized two new thermally activated delayed fluorescence(TADF)emitters that ena...High-performance nondoped organic light-emitting diodes(OLEDs)are promising technologies for future commercial applications.Herein,we synthesized two new thermally activated delayed fluorescence(TADF)emitters that enable us,for the first time,to combine three effective approaches for enhancing the efficiency of nondoped OLEDs.First,the two emitters are designed to have high steric hindrances such that their emitting cores will be suitably isolated from those of their neighbors to minimize concentration quenching.On the other hand,each of the two emitters has two stable conformations in solid films.In their neat films,molecules with the minority conformation behave effectively as dopants in the matrix composing of the majority conformation.One hundred percent exciton harvesting is thus theoretically feasible in this unique architecture of“self-doped”neat films.Furthermore,both emitters have relatively high aspect ratios in terms of their molecular shapes.This leads to films with preferred molecular orientations enabling high populations of horizontal dipoles beneficial for optical outcoupling.With these three factors,OLEDs with nondoped emitting layers of the respective emitters both achieve nearly 100%exciton utilization and deliver over 30%external quantum efficiencies and ultralow efficiency roll-off at high brightness,which have not been observed in reported nondoped OLEDs.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:51821002,52003185,52003186,52130304National Key Research&Development Program of China,Grant/Award Numbers:2020YFA0714601,2020YFA0714604+2 种基金Suzhou Key Laboratory of Functional Nano&Soft MaterialsCollaborative Innovation Center of Suzhou Nano Science&Technologythe 111 Project。
文摘High-performance nondoped organic light-emitting diodes(OLEDs)are promising technologies for future commercial applications.Herein,we synthesized two new thermally activated delayed fluorescence(TADF)emitters that enable us,for the first time,to combine three effective approaches for enhancing the efficiency of nondoped OLEDs.First,the two emitters are designed to have high steric hindrances such that their emitting cores will be suitably isolated from those of their neighbors to minimize concentration quenching.On the other hand,each of the two emitters has two stable conformations in solid films.In their neat films,molecules with the minority conformation behave effectively as dopants in the matrix composing of the majority conformation.One hundred percent exciton harvesting is thus theoretically feasible in this unique architecture of“self-doped”neat films.Furthermore,both emitters have relatively high aspect ratios in terms of their molecular shapes.This leads to films with preferred molecular orientations enabling high populations of horizontal dipoles beneficial for optical outcoupling.With these three factors,OLEDs with nondoped emitting layers of the respective emitters both achieve nearly 100%exciton utilization and deliver over 30%external quantum efficiencies and ultralow efficiency roll-off at high brightness,which have not been observed in reported nondoped OLEDs.
基金supported by the National Natural Science Foundation of China (51773029, 51533005 and 51373190)the National Key Research & Development Program of China (2016YFB0401002)+1 种基金Collaborative Innovation Center of Suzhou Nano Science & Technology, the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the 111 Project and Qing Lan Project, China
