The control of the condensed superstructure of light-emitting conjugated polymers(LCPs)is a crucial factor to obtain high performance and stable organic optoelectronic devices.Side-chain engineering strategy is an eff...The control of the condensed superstructure of light-emitting conjugated polymers(LCPs)is a crucial factor to obtain high performance and stable organic optoelectronic devices.Side-chain engineering strategy is an effective platform to tune inter chain aggregation and photophysical behaviour of LCPs.Herein,we systematically investigated the alkyl-chain branched effecton the conformational transition and photophysical behaviour of polydiarylfluorenes toward efficient blue optoelectronic devices.The branched side chain will improve materials solubility to inhibit interchain aggregation in solution according to DLS and optical analysis,which is useful to obtain high quality film.Therefore,our branched PEODPF,POYDPF pristine film present high luminance efficiency of 36.1%and 39.6%,enhanced about 20%relative to that of PODPF.Compared to the liner-type sides'chain,these branched chains also suppress chain planarization and improve film morphological stability effectively.Interestingly,the branched polymer also had excellent stable amplified spontaneous emission(ASE)behaviour with low threshold(4.72μJ/cm2)and a center peak of 465 nm,even thermal annealing at 220℃in the air atmosphere.Therefore,side-chain branched strategy for LCPs is an effective means to control interchain aggregation,film morphology and photophysical property of LCPs.展开更多
Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular...Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular emitter with a flexible side chain always presents easily aggregation upon external treatment, and caused π-electronic coupling, which is undesirable for the efficiency and stability of deep-blue OLEDs. Herein, we proposed a side-chain coupling strategy to enhance the film morphological an emission stability of solution-processable small molecular deep-blue emitter. In contrary to “parent” MC8 TPA,the crosslinkable styryl and vinyl units were introduced as ended unit at the side-chain of Cm TPA and OEYTPA. Interestingly, Cm TPA and OEYTPA films present a relatively stable morphology and uniform deep-blue emission after thermal annealing(160 ℃) in the atmosphere, different to the discontinuous MC8 TPA annealed film. Besides, compared to the Cm TPA and OEYTPA ones, serious polaron formation in the MC8 TPA annealed film also negative to the deep-blue emission, according to transient absorption analysis. Therefore, both Cm TPA and OEYTPA annealed film obtained at 140 ℃ present an excellent deep-blue ASE behavior with a 445 nm, but absence for MC8 TPA ones, associated with the disruption of annealed films. Finally, enhancement of device performance based on Cm TPA and OEYTPA film(~40%)after thermal annealing with a similar performance curves also confirmed the assumption above. Therefore, these results also supported the effectiveness of our side-chain coupling strategy for optoelectronic applications.展开更多
π-Electron coupling of pendant conjugated segment inπ-stacked semiconducting polymers always causes the formation of defect trapped sites and further quenched high-band excitons,which is harmful to the performance a...π-Electron coupling of pendant conjugated segment inπ-stacked semiconducting polymers always causes the formation of defect trapped sites and further quenched high-band excitons,which is harmful to the performance and stability of deep-blue polymer light-emitting diodes(PLEDs).Herein,considerate of“defect”carbazole(Cz)electromers in poly(N-vinylcarbazole)(PVK),a series of fluorene units are introduced into pendant segments(PVCz-DMeF,PVCz-FMeNPh and PVCz-DFMeNPh)to suppress the strongπ-electron coupling of pendant Cz units and enhance radiative transition toward fabricating sable PLEDs.Compared to PVCz-FMeNPh and PVCz-DFMeNPh,PVCz-DMeF spin-coated films show a relatively efficient deep-blue emission,completely similar to its single pendant chromophore,confirmed an extremely weak charge-transfer and electron coupling between adjacent pendant segments.Therefore,PLEDs based on PVCz-DMeF present stable and deep-blue emission with a high color purity(0.17,0.08),associated with extremely weak defect emission at 600∼700nm(induced by carbazole electromers).Finally,PLEDs based on PVCz-DMeF/F8BT blended films(1:1)also present the high maximum luminance(Lmax)of 6261 cd/m2 and current efficiency(CE_(max))of 2.03 cd/A,confirmed slightly trapped sites formation.Therefore,precisely control the arrangement and packing model of pendant units inπ-stacked polymer is an essential prerequisite for building efficient and stable emitter for optoelectronic devices.展开更多
Deep-blue emitter with high photoluminescence efficiency(PLQY)is highly desirable in ultra-high definition displays and white solid-state lightings.In this work,two deep-blue phenanthro[9,10]imidazole derivatives,PPIS...Deep-blue emitter with high photoluminescence efficiency(PLQY)is highly desirable in ultra-high definition displays and white solid-state lightings.In this work,two deep-blue phenanthro[9,10]imidazole derivatives,PPIS and PPPIS,with hot exciton property are successfully developed.Compared to PPIS,the embedded phenyl bridge in PPPIS is able to effectively increase the overlap of frontier molecular orbitals.In consequence,PPPIS shows higher oscillator strength and significantly enhanced PLQY.PPPIS also achieves better electroluminescence performance in non-doped device,showing deep-blue emission with Commission International de l’Eclairage(CIE)coordinates of(0.153,0.087)and the maximum external quantum efficiency(EQEmax)of 8.5%with minuscule efficiency roll-off.Meanwhile,when PPPIS serves as the host for phosphor PO-01,high-efficiency orange phosphorescent device is obtained with high EQEmax of 29.8%and negligible efficiency roll-off at 1000 cd/m^(2).Further,efficient single-emissive-layer white device is assembled via utilizing PPPIS as a blue emitter as well as the host for PO-01 simultaneously,providing warm-white emission with CIE coordinates of(0.429,0.433)at 1000 cd/m^(2),the forward-viewing EQEmaxof 27.2%and maximum power efficiency(PEmax)of 80.1 lm/W,respectively.Our studies can establish a viable design strategy for deep-blue emitters in high-performance non-doped blue OLEDs and hybrid WOLEDs.展开更多
Molecular-level encapsulation of conjugated polymers serves as a potent approach to isolate the conjugated backbone for reducing intermolecular interactions and manipulating optoelectronic properties in solid state.He...Molecular-level encapsulation of conjugated polymers serves as a potent approach to isolate the conjugated backbone for reducing intermolecular interactions and manipulating optoelectronic properties in solid state.Herein,by tuning the generation of dendritic carbazoles(Cz)in side chains,polydiarylfluorenes with efficient deep-blue emission have been successfully synthesized and explored.The nonplanar twisted Cz dendrons endow their photoluminescence(PL)spectra with enhanced air-aging stability and thermal stability owing to the formation of a self-encapsulation layer.Their impact on solutionstate chain conformation and aggregation was thoroughly studied,combining small-angle neutron scattering(SANS)and dynamic light scattering(DLS).Furthermore,benefiting from the suppressed intermolecular interactions,their films exhibit optimal behavior of singlet excitons in the excited state.Polymer light-emitting diodes(PLEDs)adopting the spin-coated and blade-coated films both present comparable properties and stable electroluminescence(EL)spectra,with Commission Internationale de L'Eclairage(CIE)coordinates(x+y)<0.3,demonstrating the feasibility of a self-encapsulated molecular design strategy.展开更多
To precisely control intrachain π-electron delocalization and interchain interaction simultaneously is the prerequisite to obtain stable and efficient deep-blue light-emitting p-n polymer semiconductors for the polym...To precisely control intrachain π-electron delocalization and interchain interaction simultaneously is the prerequisite to obtain stable and efficient deep-blue light-emitting p-n polymer semiconductors for the polymer light-emitting diodes(PLEDs).Herein,we introduced the steric carbazole-fluorene nanogrid into light-emitting diphenyl sulfone-based p-n polymer semiconductors(PG and PDG) via metal-free C-N coupling polymerization for the fabrication of deep-blue PLEDs.The steric,rigid and twisted configuration between nanogrid and diphenyl sulfone in PG and PDG present the unique characteristic of large steric hindrance interaction to suppress interchain aggregation in solid state.Due to the different length of electron-deficient diphenyl sulfone monomers,PG showed a deep-blue emission with a maximum peak at 428 nm but red-shifted to 480 nm for the PDG films.Interestingly,similar deep-blue emission behavior of PG in diluted non-polar solution and films suggested the extremely weak interchain aggregation.Finally,PLEDs based on PG are fabricated with a stable deep-blue emission of CIE(0.15,0.10),and corresponding EL spectral profile is also completely identical to PL ones of diluted solution,revealed the intrachain emission without obvious interchain excited state,confirmed effectiveness of the steric hindrance functionalization of nanogrid in p-n polymer semiconductor for deep-blue light-emitting organic optoelectronics.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
A new anthracene derivative 9,10-bis[3,5-di(4-tert-butylphenyl)phenyl]anthracene (BPPA) was synthesized via Suzuki coupling reaction and characterized by 1H NMR spectrum,mass spectrum,and elemental analysis.BPPA exhib...A new anthracene derivative 9,10-bis[3,5-di(4-tert-butylphenyl)phenyl]anthracene (BPPA) was synthesized via Suzuki coupling reaction and characterized by 1H NMR spectrum,mass spectrum,and elemental analysis.BPPA exhibits deep-blue emission both in solution and in solid thin film.This compound has a non-planar structure that results in high thermal stability and the phenomenon of polymorphism.The non-doped device based on this material shows stable deep-blue emission with the 1931 Commission international de I'Eclairage (CIE) coordinate of (0.15,0.05) under different applied voltages.The device exhibits the maximum external quantum efficiency of 2.2% at 14.9 mA/cm2 with luminance of 105 cd/m2.展开更多
Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of de...Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of deep-blue(<460 nm)PeLEDs still lag far behind their red and green counterparts.Herein,a rapid crystallization method based on hot-antisolvent bathing is proposed for realization of deep-blue PeLEDs.By promoting immediate removal of the precursor solvent from the wet perovskite films,development of the quasi-two-dimensional(2D)Ruddlesden–Popper perovskite(2D-RPP)crystals with n values>3 is hampered completely,so that phase-pure 2D-RPP films with bandgaps suitable for deep-blue PeLEDs can be obtained successfully.The uniquely developed rapid crystallization method also enables formation of randomly oriented 2D-RPP crystals,thereby improving the transfer and transport kinetics of the charge carriers.Thus,high-performance deep-blue PeLEDs emitting at 437 nm with a peak EQE of 0.63%are successfully demonstrated.The color coordinates are confirmed to be(0.165,0.044),which match well with the Rec.2020 standard blue gamut and have excellent spectral stability.展开更多
The development of high-performance organic blue light-emitting emitters is in urgent to act as an excitation source to contribute the white light generation.On the other hand,the investigation on optical waveguides h...The development of high-performance organic blue light-emitting emitters is in urgent to act as an excitation source to contribute the white light generation.On the other hand,the investigation on optical waveguides have been received increasing attentions because they can manipulate the light propagation accurately in the microscale to boost the optoelectronic and energy conversion applications.In this work,we facilely prepared a deep-blue aggregation-induced emission(AIE)dye,namely TPP-4OMe,which shows high luminescent efficiency,narrow emission band and good stability in the aggregate state.TPP-4OMe can be fabricated as deep-blue AIE microfibers readily with definite morphology and composition.Based on the AIE microfibers,the active waveguide to transmit deep-blue emission signals can be achieved with a very low optical loss coefficient(α)of 6.7×10^(−3)dBμm^(−1).Meanwhile,the full-visible broadband low-loss passive waveguide can be well performed with these AIE microfibers,which has never been observed in the pure organic crystals.More interestingly,the excellent properties of AIE microfibers enable them to act as a wave-guiding excitation source,resulting in a distinct and pure white light emission.The present work not only provides excellent blue light-emitting materials but also bridges the waveguide to realize the efficient white light emission to accelerate the practical applications.展开更多
High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for explo...High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency roll-off.The CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.展开更多
In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investig...In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investigated. By linking TPE to the oxadiazole core through meta-or para-position, the intramolecular conjugation is effectively controlled. Thanks to the intelligent molecular design and specific AIE feature, when fabricated as emissive layers in non-doped OLEDs, they exhibit blue or deep-blue emission with CIE coordinates of (0.17, 0.23) and (0.15, 0.12), and good efficiencies with ηC, max and ηP, max up to 1.52 cd A-1 and 0.84 Im W-1 , shedding some light on the construction of deep-blue AIE fluorophores.展开更多
In this paper,two AIE-active luminogens(Oxa-pTPE and Oxa-mTPE)constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal,optical and electronic properties were investigated...In this paper,two AIE-active luminogens(Oxa-pTPE and Oxa-mTPE)constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal,optical and electronic properties were investigated.By linking TPE to the oxadiazole core through meta-or para-position,the intramolecular conjugation is effectively controlled.Thanks to the intelligent molecular design and specific AIE feature,when fabricated as emissive layers in non-doped OLEDs,they exhibit blue or deep-blue emission with CIE coordinates of(0.17,0.23)and(0.15,0.12),and good efficiencies with ηC,max and ηP,max up to 1.52 cd A-1and 0.84 ImW -1,shedding some light on the construction of deep-blue AIE fluorophores.展开更多
Despite the rapid development of organic light-emitting diodes(OLEDs) in the field of displays,obtaining deep-blue OLEDs with high efficiency,small full-width at half-maximum(FWHM),and low efficiency roll-off is still...Despite the rapid development of organic light-emitting diodes(OLEDs) in the field of displays,obtaining deep-blue OLEDs with high efficiency,small full-width at half-maximum(FWHM),and low efficiency roll-off is still a challenge.Herein,we report a new strategy to develop an efficient and narrow-band deep-blue emitter based on tetradentate Pt(Ⅱ),labeled Pt KW1;this approach involved increasing the ^(3)LE character of the lowest triplet state(T_(1)) by extending the π conjugation in the carbazole moiety,followed by locking the N-heterocyclic carbene(NHC) and phenyl moiety with a six-membered alkyl ring,aiming to enhance the molecular rigidity.Satisfactorily,PtKW1 showed a low Huang-Rhys factor(S_(M)) value of 0.285 and an FWHM of only 18.4 nm in dichloromethane at room temperature.Furthermore,a PtKW1-doped exciplex host film exhibited a quantum efficiency of up to 99% and a short excited state lifetime of 3.17 μs.A PtKW1-doped deep-blue OLED achieved an FWHM of26 nm,Commission Internationale de l'Eclairage(CIE) coordinates of(0.125,0.189),a maximum luminescent brightness(L_(max))of up to 41074 cd/m^(2),and a maximum external quantum efficiency(EQE_(max)) of 27.4%,with a low-efficiency roll-off rate of only1.46% at 1000 cd/m^(2).This work provides new insights for designing robust,narrow-band tetradentate Pt(Ⅱ) emitters to develop highly efficient and stable deep-blue OLEDs with low efficiency roll-off and high luminescence.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61874053,21774061,91833306)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,PAPD(No.YX03002)+10 种基金the Six Peak Talents Foundation of Jiangsu Province(No.XCL-CXTD-009)Natural Science Funds of the Education Committee of Jiangsu Province(No.18KJA430009)"High-Level Talents in Six Industries"of Jiangsu Province(No.XYDXX-019)Program for Postgraduates Research Innovation in University of Jiangsu Province(No.KYCX17_0752)the open research fund from Key Laboratory for Organic Electronics and Information Display&and State Key Laboratory of Supramolecular Structure and Materials(No.sklssm2019017)Overseas Merit Foundation of Science and Technology of Nanjingfinancial support from the Regional Government of Madrid through NMAT2D-CM Project(No.S2018/NMT-4511)the Spanish Ministry of Economy and Competitiveness through project RTI2018-097508-B-I00through the Severo Ochoa Program for Centers of Excellence(No.SEV-2016-0686)the Campus of International Excellence(CEI)UAM+CSICthe China Scholarship Council(No.201608390023)for a PhD sponsorship
文摘The control of the condensed superstructure of light-emitting conjugated polymers(LCPs)is a crucial factor to obtain high performance and stable organic optoelectronic devices.Side-chain engineering strategy is an effective platform to tune inter chain aggregation and photophysical behaviour of LCPs.Herein,we systematically investigated the alkyl-chain branched effecton the conformational transition and photophysical behaviour of polydiarylfluorenes toward efficient blue optoelectronic devices.The branched side chain will improve materials solubility to inhibit interchain aggregation in solution according to DLS and optical analysis,which is useful to obtain high quality film.Therefore,our branched PEODPF,POYDPF pristine film present high luminance efficiency of 36.1%and 39.6%,enhanced about 20%relative to that of PODPF.Compared to the liner-type sides'chain,these branched chains also suppress chain planarization and improve film morphological stability effectively.Interestingly,the branched polymer also had excellent stable amplified spontaneous emission(ASE)behaviour with low threshold(4.72μJ/cm2)and a center peak of 465 nm,even thermal annealing at 220℃in the air atmosphere.Therefore,side-chain branched strategy for LCPs is an effective means to control interchain aggregation,film morphology and photophysical property of LCPs.
基金supported by the National Natural Science Foundation of China (Nos.22075136,61874053)National Key Research and Development Program of China (No.2020YFA0709900)+5 种基金Natural Science Funds of the Education Committee of Jiangsu Province (No.18KJA430009)Natural Science Foundation of Jiangsu Province (No.BK20200700)“High-Level Talents in Six Industries” of Jiangsu Province (No.XYDXX-019)Chain Postdoctoral Science Foundation (No.2021M692623)the open research fund from State Key Laboratory of Supramolecular Structure and Materials (No.sklssm202108)Anhui Province Key Laboratory of Environmentfriendly Polymer Materials and Anhui Province Key Laboratory of Optoelectronic Materials Science and Technology。
文摘Film morphology of emissive layers is crucial to the performance and stability of solution-processable organic light-emitting diodes(OLEDs). Compared to the interpenetration of conjugated polymer chain,small molecular emitter with a flexible side chain always presents easily aggregation upon external treatment, and caused π-electronic coupling, which is undesirable for the efficiency and stability of deep-blue OLEDs. Herein, we proposed a side-chain coupling strategy to enhance the film morphological an emission stability of solution-processable small molecular deep-blue emitter. In contrary to “parent” MC8 TPA,the crosslinkable styryl and vinyl units were introduced as ended unit at the side-chain of Cm TPA and OEYTPA. Interestingly, Cm TPA and OEYTPA films present a relatively stable morphology and uniform deep-blue emission after thermal annealing(160 ℃) in the atmosphere, different to the discontinuous MC8 TPA annealed film. Besides, compared to the Cm TPA and OEYTPA ones, serious polaron formation in the MC8 TPA annealed film also negative to the deep-blue emission, according to transient absorption analysis. Therefore, both Cm TPA and OEYTPA annealed film obtained at 140 ℃ present an excellent deep-blue ASE behavior with a 445 nm, but absence for MC8 TPA ones, associated with the disruption of annealed films. Finally, enhancement of device performance based on Cm TPA and OEYTPA film(~40%)after thermal annealing with a similar performance curves also confirmed the assumption above. Therefore, these results also supported the effectiveness of our side-chain coupling strategy for optoelectronic applications.
基金supported by the National Natural Science Foundation of China(Nos.22105099 and 61874053)Natural Science Foundation of Jiangsu Province(No.BK20200700)+2 种基金the China Postdoctoral Science Foundation(No.2022M711591)the open research fund from Anhui Province Key Laboratory of Optoelectronic Materials Science and Technology(No.OMST202101)the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology).
文摘π-Electron coupling of pendant conjugated segment inπ-stacked semiconducting polymers always causes the formation of defect trapped sites and further quenched high-band excitons,which is harmful to the performance and stability of deep-blue polymer light-emitting diodes(PLEDs).Herein,considerate of“defect”carbazole(Cz)electromers in poly(N-vinylcarbazole)(PVK),a series of fluorene units are introduced into pendant segments(PVCz-DMeF,PVCz-FMeNPh and PVCz-DFMeNPh)to suppress the strongπ-electron coupling of pendant Cz units and enhance radiative transition toward fabricating sable PLEDs.Compared to PVCz-FMeNPh and PVCz-DFMeNPh,PVCz-DMeF spin-coated films show a relatively efficient deep-blue emission,completely similar to its single pendant chromophore,confirmed an extremely weak charge-transfer and electron coupling between adjacent pendant segments.Therefore,PLEDs based on PVCz-DMeF present stable and deep-blue emission with a high color purity(0.17,0.08),associated with extremely weak defect emission at 600∼700nm(induced by carbazole electromers).Finally,PLEDs based on PVCz-DMeF/F8BT blended films(1:1)also present the high maximum luminance(Lmax)of 6261 cd/m2 and current efficiency(CE_(max))of 2.03 cd/A,confirmed slightly trapped sites formation.Therefore,precisely control the arrangement and packing model of pendant units inπ-stacked polymer is an essential prerequisite for building efficient and stable emitter for optoelectronic devices.
基金financial support from National Natural Science Foundation of China(No.22075100)the Jilin Provincial Science and Technology Department(No.20220201082GX)+2 种基金the China Postdoctoral Science Foundation(Nos.2022TQ0111,2023M731267)Sichuan Science and Technology Program(No.2023NSFSC0985)Scientific Research Foundation of Chengdu University of Information Technology(No.KYTZ202174)and the Changsha Automobile Innovation Research Institute。
文摘Deep-blue emitter with high photoluminescence efficiency(PLQY)is highly desirable in ultra-high definition displays and white solid-state lightings.In this work,two deep-blue phenanthro[9,10]imidazole derivatives,PPIS and PPPIS,with hot exciton property are successfully developed.Compared to PPIS,the embedded phenyl bridge in PPPIS is able to effectively increase the overlap of frontier molecular orbitals.In consequence,PPPIS shows higher oscillator strength and significantly enhanced PLQY.PPPIS also achieves better electroluminescence performance in non-doped device,showing deep-blue emission with Commission International de l’Eclairage(CIE)coordinates of(0.153,0.087)and the maximum external quantum efficiency(EQEmax)of 8.5%with minuscule efficiency roll-off.Meanwhile,when PPPIS serves as the host for phosphor PO-01,high-efficiency orange phosphorescent device is obtained with high EQEmax of 29.8%and negligible efficiency roll-off at 1000 cd/m^(2).Further,efficient single-emissive-layer white device is assembled via utilizing PPPIS as a blue emitter as well as the host for PO-01 simultaneously,providing warm-white emission with CIE coordinates of(0.429,0.433)at 1000 cd/m^(2),the forward-viewing EQEmaxof 27.2%and maximum power efficiency(PEmax)of 80.1 lm/W,respectively.Our studies can establish a viable design strategy for deep-blue emitters in high-performance non-doped blue OLEDs and hybrid WOLEDs.
基金support from the National Natural Science Foundation of China(No.62205141,62105262,62288102,22075136,62405134)supported by the Natural Science Funds of the Education Committee of Jiangsu Province(No.23KJA430010)+5 种基金the Open Fund of the Key Labora-tory of Advanced Display and System Applications,Min-istry of Education,Shanghai University(OF202505)supported by the Natural Science Foundation of Jiangsu Province for Youth(No.BK20230342)supported by the China Postdoctoral Science Foundation(No.2024M753737)the Shenzhen Science and Tech-nology Program(No.RCBS20231211090610014)support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX25-1710)The SANS experiments were performed on the small-angle neutron scattering instrument at the China Spallation Neutron Source(CSNS),Dongguan,China(Project ID:P0123122600014).
文摘Molecular-level encapsulation of conjugated polymers serves as a potent approach to isolate the conjugated backbone for reducing intermolecular interactions and manipulating optoelectronic properties in solid state.Herein,by tuning the generation of dendritic carbazoles(Cz)in side chains,polydiarylfluorenes with efficient deep-blue emission have been successfully synthesized and explored.The nonplanar twisted Cz dendrons endow their photoluminescence(PL)spectra with enhanced air-aging stability and thermal stability owing to the formation of a self-encapsulation layer.Their impact on solutionstate chain conformation and aggregation was thoroughly studied,combining small-angle neutron scattering(SANS)and dynamic light scattering(DLS).Furthermore,benefiting from the suppressed intermolecular interactions,their films exhibit optimal behavior of singlet excitons in the excited state.Polymer light-emitting diodes(PLEDs)adopting the spin-coated and blade-coated films both present comparable properties and stable electroluminescence(EL)spectra,with Commission Internationale de L'Eclairage(CIE)coordinates(x+y)<0.3,demonstrating the feasibility of a self-encapsulated molecular design strategy.
基金the support from the Jiangsu Provincial Senior Talent Program (Dengfeng,Jiangsu University)the support from the National Key R&D Program of China (No.2024YFB3612600)+3 种基金the National Natural Science Foundation of China (Nos.22275098,62288102)Basic Research Program of Jiangsu (No.BK20243057)the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications (No.NY222097)the National Natural Science Foundation of China (No.62205035)。
文摘To precisely control intrachain π-electron delocalization and interchain interaction simultaneously is the prerequisite to obtain stable and efficient deep-blue light-emitting p-n polymer semiconductors for the polymer light-emitting diodes(PLEDs).Herein,we introduced the steric carbazole-fluorene nanogrid into light-emitting diphenyl sulfone-based p-n polymer semiconductors(PG and PDG) via metal-free C-N coupling polymerization for the fabrication of deep-blue PLEDs.The steric,rigid and twisted configuration between nanogrid and diphenyl sulfone in PG and PDG present the unique characteristic of large steric hindrance interaction to suppress interchain aggregation in solid state.Due to the different length of electron-deficient diphenyl sulfone monomers,PG showed a deep-blue emission with a maximum peak at 428 nm but red-shifted to 480 nm for the PDG films.Interestingly,similar deep-blue emission behavior of PG in diluted non-polar solution and films suggested the extremely weak interchain aggregation.Finally,PLEDs based on PG are fabricated with a stable deep-blue emission of CIE(0.15,0.10),and corresponding EL spectral profile is also completely identical to PL ones of diluted solution,revealed the intrachain emission without obvious interchain excited state,confirmed effectiveness of the steric hindrance functionalization of nanogrid in p-n polymer semiconductor for deep-blue light-emitting organic optoelectronics.
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 National Natural Science Foundation of China (50773090,50825304,51033007)
文摘A new anthracene derivative 9,10-bis[3,5-di(4-tert-butylphenyl)phenyl]anthracene (BPPA) was synthesized via Suzuki coupling reaction and characterized by 1H NMR spectrum,mass spectrum,and elemental analysis.BPPA exhibits deep-blue emission both in solution and in solid thin film.This compound has a non-planar structure that results in high thermal stability and the phenomenon of polymorphism.The non-doped device based on this material shows stable deep-blue emission with the 1931 Commission international de I'Eclairage (CIE) coordinate of (0.15,0.05) under different applied voltages.The device exhibits the maximum external quantum efficiency of 2.2% at 14.9 mA/cm2 with luminance of 105 cd/m2.
基金National R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Grant Nos.2018M3D1A1058793 and 2021R1A3B1068920)the Yonsei Signature Research Cluster Program of 2021(Grant No.2021-22-0002).
文摘Perovskite light-emitting diodes(PeLEDs)are considered as promising candidates for nextgeneration solution-processed full-color displays.However,the external quantum efficiencies(EQEs)and operational stabilities of deep-blue(<460 nm)PeLEDs still lag far behind their red and green counterparts.Herein,a rapid crystallization method based on hot-antisolvent bathing is proposed for realization of deep-blue PeLEDs.By promoting immediate removal of the precursor solvent from the wet perovskite films,development of the quasi-two-dimensional(2D)Ruddlesden–Popper perovskite(2D-RPP)crystals with n values>3 is hampered completely,so that phase-pure 2D-RPP films with bandgaps suitable for deep-blue PeLEDs can be obtained successfully.The uniquely developed rapid crystallization method also enables formation of randomly oriented 2D-RPP crystals,thereby improving the transfer and transport kinetics of the charge carriers.Thus,high-performance deep-blue PeLEDs emitting at 437 nm with a peak EQE of 0.63%are successfully demonstrated.The color coordinates are confirmed to be(0.165,0.044),which match well with the Rec.2020 standard blue gamut and have excellent spectral stability.
基金National Natural Science Foundation of China,Grant/Award Numbers:22275072,11804120,61827822,51620105009Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2023A1515030209+2 种基金Research Projects from Guangzhou,Grant/Award Number:2023A03J0018Shenzhen Key Laboratory of Functional Aggregate Materials,Grant/Award Number:ZDSYS20211021111400001the Science Technology Innovation Commission of Shenzhen Municipality,Grant/Award Numbers:KQTD20210811090142053,JCYJ20220818103007014。
文摘The development of high-performance organic blue light-emitting emitters is in urgent to act as an excitation source to contribute the white light generation.On the other hand,the investigation on optical waveguides have been received increasing attentions because they can manipulate the light propagation accurately in the microscale to boost the optoelectronic and energy conversion applications.In this work,we facilely prepared a deep-blue aggregation-induced emission(AIE)dye,namely TPP-4OMe,which shows high luminescent efficiency,narrow emission band and good stability in the aggregate state.TPP-4OMe can be fabricated as deep-blue AIE microfibers readily with definite morphology and composition.Based on the AIE microfibers,the active waveguide to transmit deep-blue emission signals can be achieved with a very low optical loss coefficient(α)of 6.7×10^(−3)dBμm^(−1).Meanwhile,the full-visible broadband low-loss passive waveguide can be well performed with these AIE microfibers,which has never been observed in the pure organic crystals.More interestingly,the excellent properties of AIE microfibers enable them to act as a wave-guiding excitation source,resulting in a distinct and pure white light emission.The present work not only provides excellent blue light-emitting materials but also bridges the waveguide to realize the efficient white light emission to accelerate the practical applications.
基金supported by the National Natural Science Foundation of China(52103220,51922021,52273164)the Shandong Provincial Natural Science Foundation(ZR2022ZD37,ZR2019ZD50).
文摘High-efficiency thermally activated delayed fluorescence(TADF) emitters and corresponding well-designed solution-processed organic light emitting diodes(OLEDs) are presently attractive due to their potential for exploiting large-area flexible displays. In this context, we innovatively integrate 2,12-di-tert-butyl-5,9-dioxa-13b-boronaphtho [3,2,1] anthracene as the acceptor with 3,6-bis(3,6-di-tert-butylcarbazol-N-yl) carbazole as the donor to construct a rigid deep-blue emitter, TB-3t BuCz, which exhibits a narrow emission with full-width-at-half-maximum(FWHM) of 46 nm. TB-3t BuCz itself dispalys no TADF characteristics both in solution or in pure film states. However, the significant TADF behavior can be observed when TB-3t BuCz is doped with 2,6-DCzPPy host due to the formation of exciplex-like species in 2,6-DCzPPy/TB-3t BuCz system. It is also found that the discernible spin-flip of triplet excitons is feasible when the S1/T1states of the formed exciplex stay slightly lower than S1 and T1states of TB-3t BuCz for the other host/TB-3t BuCz systems. Eventually, thanks to the synergetic effect of rigid structure and favorable photophysical properties of TB-3t BuCz, the solution-processed OLEDs based on 2,6-DCzPPy/TB-3t BuCz as emitting layer has achieved the significantly improved external quantum efficiency(EQE) of 14.6% with suppressed efficiency roll-off.The CIE1931 coordinate of(0.158, 0.052) is typically in deep-blue region. Note that, this EQE value is among the highest echelon of solution-processed OLEDs with deep-blue emission by utilizing boron-containing TADF emitters.
基金the National Science Foundation of China(21161160556)the National Basic Research Program(973program,2013CB834700)the Open Project of State Key Laboratory of Supramolecular Structure and Materials(SKLSSM201302)
文摘In this paper, two AIE-active luminogens (Oxa-pTPE and Oxa-mTPE) constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal, optical and electronic properties were investigated. By linking TPE to the oxadiazole core through meta-or para-position, the intramolecular conjugation is effectively controlled. Thanks to the intelligent molecular design and specific AIE feature, when fabricated as emissive layers in non-doped OLEDs, they exhibit blue or deep-blue emission with CIE coordinates of (0.17, 0.23) and (0.15, 0.12), and good efficiencies with ηC, max and ηP, max up to 1.52 cd A-1 and 0.84 Im W-1 , shedding some light on the construction of deep-blue AIE fluorophores.
文摘In this paper,two AIE-active luminogens(Oxa-pTPE and Oxa-mTPE)constructed from tetraphenylethene and oxadiazole units were successfully synthesized and their thermal,optical and electronic properties were investigated.By linking TPE to the oxadiazole core through meta-or para-position,the intramolecular conjugation is effectively controlled.Thanks to the intelligent molecular design and specific AIE feature,when fabricated as emissive layers in non-doped OLEDs,they exhibit blue or deep-blue emission with CIE coordinates of(0.17,0.23)and(0.15,0.12),and good efficiencies with ηC,max and ηP,max up to 1.52 cd A-1and 0.84 ImW -1,shedding some light on the construction of deep-blue AIE fluorophores.
基金supported by the National Natural Science Foundation of China (22178319,22478357,22138011)the Zhejiang Province Vanguard Goose-Leading Initiative (2024C01260)。
文摘Despite the rapid development of organic light-emitting diodes(OLEDs) in the field of displays,obtaining deep-blue OLEDs with high efficiency,small full-width at half-maximum(FWHM),and low efficiency roll-off is still a challenge.Herein,we report a new strategy to develop an efficient and narrow-band deep-blue emitter based on tetradentate Pt(Ⅱ),labeled Pt KW1;this approach involved increasing the ^(3)LE character of the lowest triplet state(T_(1)) by extending the π conjugation in the carbazole moiety,followed by locking the N-heterocyclic carbene(NHC) and phenyl moiety with a six-membered alkyl ring,aiming to enhance the molecular rigidity.Satisfactorily,PtKW1 showed a low Huang-Rhys factor(S_(M)) value of 0.285 and an FWHM of only 18.4 nm in dichloromethane at room temperature.Furthermore,a PtKW1-doped exciplex host film exhibited a quantum efficiency of up to 99% and a short excited state lifetime of 3.17 μs.A PtKW1-doped deep-blue OLED achieved an FWHM of26 nm,Commission Internationale de l'Eclairage(CIE) coordinates of(0.125,0.189),a maximum luminescent brightness(L_(max))of up to 41074 cd/m^(2),and a maximum external quantum efficiency(EQE_(max)) of 27.4%,with a low-efficiency roll-off rate of only1.46% at 1000 cd/m^(2).This work provides new insights for designing robust,narrow-band tetradentate Pt(Ⅱ) emitters to develop highly efficient and stable deep-blue OLEDs with low efficiency roll-off and high luminescence.
