Thermally activated delayed fluorescence(TADF)materials that simultaneously exhibit short-range(SR)and long-range(LR)charge-transfer(CT)excited states represent a promising new class of emitters for organic light-emit...Thermally activated delayed fluorescence(TADF)materials that simultaneously exhibit short-range(SR)and long-range(LR)charge-transfer(CT)excited states represent a promising new class of emitters for organic light-emitting diodes(OLEDs).Such systems combine the advantages of conventional donor-acceptor(D-A)and multi-resonance(MR)emitters,including high photoluminescence quantum yield(PLQY),fast radiative decay(kr)and reverse intersystem crossing rates(kRISC),and narrowband emission profiles.However,their molecular design principles and structure-property relationships remain largely unexplored.In this work,two new TADF emitters featuring both SR-CT and LR-CT excited states were developed by attaching electron donors to an MR fragment via a boron-meta-donor linkage.Together with reference compounds,these emitters enable a systematic investigation of the influence of the donor structure and linkage mode on the key photophysical properties of such light-emitting materials.Compared with conventional boron-para-donor linked emitters,the boron-meta-donor linked designs display highly hybridized SR-LR-CT character,manifested in distinctive emission bandwidths,enhanced solvatochromism,and donor-strength-dependent excited-state kinetics.Leveraging these features,high-performance narrowband OLEDs were fabricated,achieving a maximum external quantum efficiency(EQEmax)of 35.1%and exhibiting remarkably low efficiency roll-off,with an EQE of 18.1%maintained at a luminance of 10,000 cd·m^(-2).展开更多
基金support from the National Natural Science Foundation of China(52573203 and 52130308)Guangdong Basic and Applied Basic Research Foundation(2025A1515010777)+1 种基金the Shenzhen Science and Technology Program(ZDSYS20210623091813040 and JCYJ20220818095816036)Research Team Cultivation Program of Shenzhen University(2023DFT004)。
文摘Thermally activated delayed fluorescence(TADF)materials that simultaneously exhibit short-range(SR)and long-range(LR)charge-transfer(CT)excited states represent a promising new class of emitters for organic light-emitting diodes(OLEDs).Such systems combine the advantages of conventional donor-acceptor(D-A)and multi-resonance(MR)emitters,including high photoluminescence quantum yield(PLQY),fast radiative decay(kr)and reverse intersystem crossing rates(kRISC),and narrowband emission profiles.However,their molecular design principles and structure-property relationships remain largely unexplored.In this work,two new TADF emitters featuring both SR-CT and LR-CT excited states were developed by attaching electron donors to an MR fragment via a boron-meta-donor linkage.Together with reference compounds,these emitters enable a systematic investigation of the influence of the donor structure and linkage mode on the key photophysical properties of such light-emitting materials.Compared with conventional boron-para-donor linked emitters,the boron-meta-donor linked designs display highly hybridized SR-LR-CT character,manifested in distinctive emission bandwidths,enhanced solvatochromism,and donor-strength-dependent excited-state kinetics.Leveraging these features,high-performance narrowband OLEDs were fabricated,achieving a maximum external quantum efficiency(EQEmax)of 35.1%and exhibiting remarkably low efficiency roll-off,with an EQE of 18.1%maintained at a luminance of 10,000 cd·m^(-2).
