A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB lay...A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB layers exhibit high anisotropy. The third-order nonlinear optical responses and susceptibilities X^（3）e of squarylium dye in 5CB are measured with light polarizations parallel and perpendicular to the orientational direction by the resonant femtosecond degenerate four-wave mixing （DFWM） technique. Temporal profiles of the DFWM signal of the oriented squarylium dye-5CB layers with light polarizations parallel and perpendicular to the orientational direction are measured with a time resolution of 0.3ps （FWHM）, and are found to consist of two components, i.e., the coherent instantaneous nonlinear response and slow response due to the formation of excited molecules. A high anisotropic ratio of x^（3）e, 10.8 ：k 1.2, is observed for the oriented layers.展开更多
Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly pol...Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly polarized organic light-emitting diodes(CP-OLEDs)needs to meet the requirements of high efficiency,high color purity,low cost,and high dissymmetry factor(gPLor gEL),chiral multiple resonance thermally activated delayed fluorescence(MR-TADF)materials are considered as candidates in these aspects.Herein,based on a pair of chiral spirofluorene precursors,two pairs of high-performance chiral MR-TADF emitters((R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB)are developed,which exhibit strong emissions peaking at 491 and 502 nm in toluene with full-width at half-maximum values of 25 and 33 nm,respectively.In addition,small singlet–triplet energy gaps of 0.15 and 0.10 eV with high absolute photoluminescence efficiencies of 95.0%and 96.7%are observed for p-Spiro-DtBuCzB and m-Spiro-DtBuCzB molecules,respectively.OLEDs based on p-Spiro-DtBuCzB and m-Spiro-DtBuCzB display high maximum external quantum efficiencies of 29.6%and 33.8%,respectively.Most importantly,CP-OLEDs present symmetric circularly polarized electroluminescence spectra with|gEL|factors of 3.36×10^(-4)and 7.66×10^(-4)for devices based on(R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB enantiomers,respectively.展开更多
Developing chiral thermally activated delayed fluorescence(TADF)materials with excellent photophysical and chiroptical properties is crucial for advancing circularly polarized organic light-emitting diodes(CP-OLED).To...Developing chiral thermally activated delayed fluorescence(TADF)materials with excellent photophysical and chiroptical properties is crucial for advancing circularly polarized organic light-emitting diodes(CP-OLED).To overcome the inherent trade-off relationship between photoluminescent quantum yield(PLQY)and dissymmetry factor(g),a fixed degenerate exciton chirality(FD-EC)strategy based on the multiple resonance TADF chromophore is proposed,exhibiting improved deep-blue emission with the peak at 454 nm and a high PLQY of 0.96,and unique exciton chirality with amplified|gabs|and|gPL|values of 1.0×10^(-3) and 1.6×10^(-3).The CP-OLED,incorporating the chiral blue emitter,exhibits standard blue emission with a narrow full width at half maximum of 30 nm,a superior external quantum efficiency of 27.8%,Commission Internationale de L'Eclairage coordinates of(0.14,0.08),and distinct circularly polarized electroluminescence.展开更多
For studies concerning circularly polarized multiple resonances thermally activated delayed fluorescence(CP-MR-TADF)emitters with central chirality,only carbon element has been applied.Herein,for the first time,we rep...For studies concerning circularly polarized multiple resonances thermally activated delayed fluorescence(CP-MR-TADF)emitters with central chirality,only carbon element has been applied.Herein,for the first time,we report a CP-MR-TADF material with phosphorus central chirality containing tert-butyl(phenyl)phosphine oxide,(R/S)-4-POtBuCzB,as enantiomers exhibiting the narrowest full-width at half-maximum(FWHM=20 nm)among the reported CP-TADF molecules,with symmetric CP photoluminescence and a dissymmetry factor(|gPL|)of 0.54×10^(-3).Concurrently,2-POtBuCzB further demonstrated that phosphine participated in photophysical performance regulation.Notably,CP organic light-emitting diodes(CP-OLEDs)using(R/S)-4-POtBuCzB showed remarkable CPEL activity with a|gEL|of 0.61×10^(-3),and OLED with 2-POtBuCzB,achieving a maximum external quantum efficiency(EQE_(max))of 37.0%.These results demonstrate that introducing chiral phosphorus fragments into the MR-TADF skeleton is an efficacious approach for CP-MR-TADF materials and devices.展开更多
文摘A squarylium dye is dissolved in 4-cyano-4＇-pentylbiphenyl （SCB） and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB layers exhibit high anisotropy. The third-order nonlinear optical responses and susceptibilities X^（3）e of squarylium dye in 5CB are measured with light polarizations parallel and perpendicular to the orientational direction by the resonant femtosecond degenerate four-wave mixing （DFWM） technique. Temporal profiles of the DFWM signal of the oriented squarylium dye-5CB layers with light polarizations parallel and perpendicular to the orientational direction are measured with a time resolution of 0.3ps （FWHM）, and are found to consist of two components, i.e., the coherent instantaneous nonlinear response and slow response due to the formation of excited molecules. A high anisotropic ratio of x^（3）e, 10.8 ：k 1.2, is observed for the oriented layers.
基金supported by the National Natural Science Foundation of China(92256304,U23A20593)。
文摘Chiral luminescence materials have potential applications in the field of three-dimensional displays due to their circularly polarized luminescence(CPL)characteristics.However,the further development of circularly polarized organic light-emitting diodes(CP-OLEDs)needs to meet the requirements of high efficiency,high color purity,low cost,and high dissymmetry factor(gPLor gEL),chiral multiple resonance thermally activated delayed fluorescence(MR-TADF)materials are considered as candidates in these aspects.Herein,based on a pair of chiral spirofluorene precursors,two pairs of high-performance chiral MR-TADF emitters((R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB)are developed,which exhibit strong emissions peaking at 491 and 502 nm in toluene with full-width at half-maximum values of 25 and 33 nm,respectively.In addition,small singlet–triplet energy gaps of 0.15 and 0.10 eV with high absolute photoluminescence efficiencies of 95.0%and 96.7%are observed for p-Spiro-DtBuCzB and m-Spiro-DtBuCzB molecules,respectively.OLEDs based on p-Spiro-DtBuCzB and m-Spiro-DtBuCzB display high maximum external quantum efficiencies of 29.6%and 33.8%,respectively.Most importantly,CP-OLEDs present symmetric circularly polarized electroluminescence spectra with|gEL|factors of 3.36×10^(-4)and 7.66×10^(-4)for devices based on(R/S)-p-Spiro-DtBuCzB and(R/S)-m-Spiro-DtBuCzB enantiomers,respectively.
基金supported by the National Key R&D Program of China(2021YFB3600605)the National Natural Science Foundation of China(52173282,22105084)the Guangdong Basic and Applied Basic Research Foundation(2024A1515012053,2023A050502-0012)。
文摘Developing chiral thermally activated delayed fluorescence(TADF)materials with excellent photophysical and chiroptical properties is crucial for advancing circularly polarized organic light-emitting diodes(CP-OLED).To overcome the inherent trade-off relationship between photoluminescent quantum yield(PLQY)and dissymmetry factor(g),a fixed degenerate exciton chirality(FD-EC)strategy based on the multiple resonance TADF chromophore is proposed,exhibiting improved deep-blue emission with the peak at 454 nm and a high PLQY of 0.96,and unique exciton chirality with amplified|gabs|and|gPL|values of 1.0×10^(-3) and 1.6×10^(-3).The CP-OLED,incorporating the chiral blue emitter,exhibits standard blue emission with a narrow full width at half maximum of 30 nm,a superior external quantum efficiency of 27.8%,Commission Internationale de L'Eclairage coordinates of(0.14,0.08),and distinct circularly polarized electroluminescence.
基金supported by the Natural Science Foundation of Jiangsu Province(grant nos.BK20243010 and BK20242021)the National Natural Science Foundation of China(grant nos.92256304 and U23A20593).
文摘For studies concerning circularly polarized multiple resonances thermally activated delayed fluorescence(CP-MR-TADF)emitters with central chirality,only carbon element has been applied.Herein,for the first time,we report a CP-MR-TADF material with phosphorus central chirality containing tert-butyl(phenyl)phosphine oxide,(R/S)-4-POtBuCzB,as enantiomers exhibiting the narrowest full-width at half-maximum(FWHM=20 nm)among the reported CP-TADF molecules,with symmetric CP photoluminescence and a dissymmetry factor(|gPL|)of 0.54×10^(-3).Concurrently,2-POtBuCzB further demonstrated that phosphine participated in photophysical performance regulation.Notably,CP organic light-emitting diodes(CP-OLEDs)using(R/S)-4-POtBuCzB showed remarkable CPEL activity with a|gEL|of 0.61×10^(-3),and OLED with 2-POtBuCzB,achieving a maximum external quantum efficiency(EQE_(max))of 37.0%.These results demonstrate that introducing chiral phosphorus fragments into the MR-TADF skeleton is an efficacious approach for CP-MR-TADF materials and devices.
