Efficient thermally activated delayed fluorescence(TADF)emitters can be developed using intramolecular through-space charge transfer(TSCT)in spiro compounds featuring a donor-σ-acceptor(D-σ-A)configuration.However,t...Efficient thermally activated delayed fluorescence(TADF)emitters can be developed using intramolecular through-space charge transfer(TSCT)in spiro compounds featuring a donor-σ-acceptor(D-σ-A)configuration.However,traditional TSCT TADF molecules often struggle with weak charge transfer,making longwavelength emission challenging.In this study,a series of efficient TSCT TADF molecules with curved structures was synthesized by incorporating heptacyclic spiro structures with various donors.Although the spiro-carbon atom disrupts through-bond conjugation,the curved molecular configuration enhances intramolecular through-space interactions.These interactions,including intramolecular carbon-carbon and hydrogen-involved interactions,increase molecular rigidity and boost photoluminescence quantum yield up to 98%.The robust intramolecular TSCT allows precise tuning of long-wavelength emissions from yellow to red(556-647 nm)in dilute toluene solutions.Organic light-emitting diodes(OLEDs)based on these molecules exhibit efficient long-wavelength electroluminescence from yellow-green to red(544-626 nm),achieving a maximum external quantum efficiency of up to 22.1%.This represents the first TSCT TADF system with D-σ-A configuration capable of producing yellow,orange,and red electroluminescence,offering new strategies for developing efficient red and near-infrared TSCT TADF emitters.展开更多
基金supported by the Research Grants Council of Hong Kong(16303221)the Innovation and Technology Commission of Hong Kong(ITC-CNERC14SC01)+6 种基金the Shenzhen Key Laboratory of Functional Aggregate Materials(ZDSYS20211021111400001)the Science Technology Innovation Commission of Shenzhen Municipality(KQTD20210811090142053,JCYJ20220818103007014)financial support from the National Natural Science Foundation of China(62175171,62375193)the Natural Science Foundation of Jiangsu Province(BK20221237)supported by the Suzhou Key Laboratory of Functional Nano&Soft Materials,Collaborative Innovation Center of Suzhou Nano Science&Technology(Nano-CIC)the 111 Projectthe Joint International Research Laboratory of Carbon-Based Functional Materials and Devices。
文摘Efficient thermally activated delayed fluorescence(TADF)emitters can be developed using intramolecular through-space charge transfer(TSCT)in spiro compounds featuring a donor-σ-acceptor(D-σ-A)configuration.However,traditional TSCT TADF molecules often struggle with weak charge transfer,making longwavelength emission challenging.In this study,a series of efficient TSCT TADF molecules with curved structures was synthesized by incorporating heptacyclic spiro structures with various donors.Although the spiro-carbon atom disrupts through-bond conjugation,the curved molecular configuration enhances intramolecular through-space interactions.These interactions,including intramolecular carbon-carbon and hydrogen-involved interactions,increase molecular rigidity and boost photoluminescence quantum yield up to 98%.The robust intramolecular TSCT allows precise tuning of long-wavelength emissions from yellow to red(556-647 nm)in dilute toluene solutions.Organic light-emitting diodes(OLEDs)based on these molecules exhibit efficient long-wavelength electroluminescence from yellow-green to red(544-626 nm),achieving a maximum external quantum efficiency of up to 22.1%.This represents the first TSCT TADF system with D-σ-A configuration capable of producing yellow,orange,and red electroluminescence,offering new strategies for developing efficient red and near-infrared TSCT TADF emitters.
