Perovskite based light-emitting diodes(PeLEDs)have become a powerful candidate for next-generation solid-state lightings and high-definition displays due to their high photoluminescence quantum yield(PLQY),tunable emi...Perovskite based light-emitting diodes(PeLEDs)have become a powerful candidate for next-generation solid-state lightings and high-definition displays due to their high photoluminescence quantum yield(PLQY),tunable emission wavelength over the visible spectrum,and narrow emission linewidths.Over the past few years,the development of red-and green-emissive PeLEDs has rapidly increased,and the corresponding external quantum efficiencies(EQE)have exceeded 20%.However,the research progress of blue-emitting PeLEDs is limited by its poor material quality and inappropriate device structure.Currently,the maximum EQE of blue PeLED is only 6.2%,which is far from the industrialization requirements.In order to promote the development of blue PeLEDs,we summarize the recent research progress of blue perovskite materials and LEDs and discuss several fatal challenges,mainly embodied in low efficiency and poor stability.In order to overcome these challenges,detailed analysis and strategies are put forward in terms of the materials and devices.For the former,we summarize the feasible strategy for the preparation of efficient and stable blue-emissive perovskites using component engineering.For the latter,we analyze the advantages and limitations of the different strategies for blue-emissive perovskite in LEDs.At the end of the review,a comprehensive outlook is detailed,including future development directions and several technical problems to be solved.Thus,we aim to highlight the significance and promote the industrialization of PeLEDs.展开更多
ZnSeTe blue Cd-free quantum dot(QD)has emerged as a promising emitter for display applications due to its nontoxicity,tunable wavelength,and high efficiency.However,ZnSeTe-based quantum-dot light-emitting diodes(QLEDs...ZnSeTe blue Cd-free quantum dot(QD)has emerged as a promising emitter for display applications due to its nontoxicity,tunable wavelength,and high efficiency.However,ZnSeTe-based quantum-dot light-emitting diodes(QLEDs)usually exhibit unsaturated emissions with broad spectra.Herein,a top-emitting structure,equipped with a transparent indium-zinc-oxide(IZO)top electrode and an IZO phase tuning layer(PTL),is developed to modulate the emission spectra and the efficiency of the devices.Saturated blue emissions with color coordinates beyond Recommendation ITU-R BT.709(Rec.709)and near Rec.2020 standards are achieved.Moreover,benefiting from the improved outcoupling efficiency and the enhanced charge balance,the top-emitting QLED demonstrates a high external quantum efficiency of 15.14%,which is further improved to 18.16%by capping the devices with SiO2 nanospheres.Simulation analysis reveals that the surface plasmon polariton(SPP)losses are effectively reduced by applying a 100 nm PTL,leading to an outcoupling efficiency of 41.2%at a wavelength of 478 nm.Due to the simultaneously enhanced color saturation and efficiency,a high chroma efficiency(current efficiency/y coordinate in Commission Internationale de l'Eclairage chart)of 123 is obtained.The developed top-emitting architecture could enable the realization of efficient and saturated QLEDs for wide color gamut high-definition display applications.展开更多
Zero-dimensional metal halides are of unique structures and tunable photoluminescence properties,showing great potential applications such as light-emitting diodes(LEDs)and sensing.Herein,we successfully synthesized C...Zero-dimensional metal halides are of unique structures and tunable photoluminescence properties,showing great potential applications such as light-emitting diodes(LEDs)and sensing.Herein,we successfully synthesized Cu^(+)doped(MA)_(2)ZnCl_(4)metal halides by a slow evaporation solvent method.The introduction of Cu^(+)results in sky-blue self-trapped exciton emission in(MA)_(2)ZnCl_(4) at 486 nm at room temperature,and a photoluminescence quantum yield is as high as 54.9%.Interestingly,at low temperatures,Cu^(+)-doped(MA)_(2)ZnCl_(4) exhibits two emission peaks located at 482 and 605 nm,respectively.This temperaturedependent dual emission indicates two excited state structures that exist on the triplet excited-state potential energy surface.In addition,the temperature sensor we fitted has good performance(Sr=1.65%·K^(−1)),which is the first attempt in Cu^(+) doped Znbased metal halides.Our work enriches the family of sky-blue metal halides and provides a promising strategy for building skyblue LEDs.展开更多
Developing highly sensitive optical thermometers is of great significance due to their capability to enable remote and non-contact temperature measurements, rendering them highly applicable in diverse and harsh enviro...Developing highly sensitive optical thermometers is of great significance due to their capability to enable remote and non-contact temperature measurements, rendering them highly applicable in diverse and harsh environments. Herein we report a temperature-dependent phosphor of 0D metal halide hybrid by incorporating Bi^(3+)into the(MePPh_(3))_(2)ZnCl_(4) matrix. Through Bi^(3+)doping,the initially non-luminescent(MePPh_(3))_(2) ZnCl_(4) matrix exhibits a deep-blue emission centered at 453 nm, with a photoluminescence quantum yield(PLQY) of 5.71% and a Stokes shift of 75 nm at room temperature. Experimental characterization demonstrates that exciton-like luminescence of Bi^(3+)is mainly responsible for the blue emission. Single crystals of Bi^(3+)-doped(MePPh_(3))_(2)ZnCl_(4) show an unusual correlation between photoluminescence(PL) lifetime and temperature. Particularly, the dependence of luminescence lifetime on temperature is most remarkable in the temperature range of 80 to 100 K with an exceptional sensitivity up to 0.09 K^(-1), representing one of the best levels for thermometry based on PL decay lifetime. Our work not only provides a viable strategy for designing a novel, environmentally friendly, and stable blue emitter, but also paves the way for precise thermometric application at low temperature.展开更多
Hyperbranched polymer structures represent a class of high-functionality building blocks with excellent three-dimensional topology for the construction of highly substituted conjugated polymers.In this contribution,an...Hyperbranched polymer structures represent a class of high-functionality building blocks with excellent three-dimensional topology for the construction of highly substituted conjugated polymers.In this contribution,an efficient microwave synthesis protocol toward the synthesis of conjugated hyperbranched polymers is presented.A novel series of soluble hyperbranched polyfluorenes (PTF1-PTF3) incorporating triazatruxene moiety as the branch units with various branching degrees have thus been successfully constructed with good yields and high molecular weight via a facile "A2+B2+C3" approach.The structures of the hyperbranched polymers were confirmed by NMR and GPC.Their thermal,optical,and electrochemical properties of the hyperbranched polymers were also investigated.The results showed that introduction of triazatruxene units into the hyperbranched structure endowed the polymer with good thermal stability and highly amorphous properties.Photophysical investigation of PTFx revealed strong blue emission in both solution and solid states.Hyperbranched polymers with higher degree of branching and proper content of linear fluorene units exhibited better photophysical properties in terms of narrow emission spectra and relatively high quantum efficiency as well as improved thermal spectral stability.The triazatruxene branching unit also played a role in raising the HOMO energy levels relative to those of polyfluorenes that would help to improve the charge injection and transport properties.The incorporation of triazatruxene unit into hyperbranched polymers has thus explored an effective avenue for constructing optoelectronic polymers with improved functional characteristics.展开更多
Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are develope...Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs).It is found that the non-conjugated polynorbornenes can keep high triplet energy(ET)levels in range of 3.12-3.20 eV by interrupting the conjugation of repeating units,making them capable as host materials for blue emitters.Meanwhile,by increasing the electron-donating capability of side chain arylamine from carbazole to acridan and dendritic teracridan,the highest occupied molecular orbital(HOMO)levels for the polymer hosts are elevated from-5.50 eV to-5.11 eV,beneficial for reducing the hole injection barrier from anode to emissive layer.As a result,solution-processed OLEDs employing polynorbornenes with dendritic teracridan side chain(PNB-TAc)as host and boron,selenium,nitrogen-containing multiple resonance thermally activated delayed fluorescence emitter as dopant reveal efficient narrowband blue electroluminescence with emission peak at 474 nm,full-width at half maximum of 30 nm,together with maximum external quantum efficiency of 20.2%,representing the state-of-the-art device efficiency for solution-processed OLEDs with narrowband blue emission.展开更多
基金supported by NSFC(61604074,61725402)the National Key Research and Development Program of China(2016YFB0401701)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20180020,BK20160827)the Fundamental Research Funds for the Central Universities(No.30917011202)PAPD of Jiangsu Higher Education Institutions,and large instrument equipment open fund of Nanjing University of Science and Technology.
文摘Perovskite based light-emitting diodes(PeLEDs)have become a powerful candidate for next-generation solid-state lightings and high-definition displays due to their high photoluminescence quantum yield(PLQY),tunable emission wavelength over the visible spectrum,and narrow emission linewidths.Over the past few years,the development of red-and green-emissive PeLEDs has rapidly increased,and the corresponding external quantum efficiencies(EQE)have exceeded 20%.However,the research progress of blue-emitting PeLEDs is limited by its poor material quality and inappropriate device structure.Currently,the maximum EQE of blue PeLED is only 6.2%,which is far from the industrialization requirements.In order to promote the development of blue PeLEDs,we summarize the recent research progress of blue perovskite materials and LEDs and discuss several fatal challenges,mainly embodied in low efficiency and poor stability.In order to overcome these challenges,detailed analysis and strategies are put forward in terms of the materials and devices.For the former,we summarize the feasible strategy for the preparation of efficient and stable blue-emissive perovskites using component engineering.For the latter,we analyze the advantages and limitations of the different strategies for blue-emissive perovskite in LEDs.At the end of the review,a comprehensive outlook is detailed,including future development directions and several technical problems to be solved.Thus,we aim to highlight the significance and promote the industrialization of PeLEDs.
基金supported by the National Natural Science Foundation of China(No.62174075)Shenzhen Science and Technology Program(Nos.JCYJ20210324105400002 and JCYJ20220530113809022)the Guangdong University Research Program(No.2020ZDZX3062).
文摘ZnSeTe blue Cd-free quantum dot(QD)has emerged as a promising emitter for display applications due to its nontoxicity,tunable wavelength,and high efficiency.However,ZnSeTe-based quantum-dot light-emitting diodes(QLEDs)usually exhibit unsaturated emissions with broad spectra.Herein,a top-emitting structure,equipped with a transparent indium-zinc-oxide(IZO)top electrode and an IZO phase tuning layer(PTL),is developed to modulate the emission spectra and the efficiency of the devices.Saturated blue emissions with color coordinates beyond Recommendation ITU-R BT.709(Rec.709)and near Rec.2020 standards are achieved.Moreover,benefiting from the improved outcoupling efficiency and the enhanced charge balance,the top-emitting QLED demonstrates a high external quantum efficiency of 15.14%,which is further improved to 18.16%by capping the devices with SiO2 nanospheres.Simulation analysis reveals that the surface plasmon polariton(SPP)losses are effectively reduced by applying a 100 nm PTL,leading to an outcoupling efficiency of 41.2%at a wavelength of 478 nm.Due to the simultaneously enhanced color saturation and efficiency,a high chroma efficiency(current efficiency/y coordinate in Commission Internationale de l'Eclairage chart)of 123 is obtained.The developed top-emitting architecture could enable the realization of efficient and saturated QLEDs for wide color gamut high-definition display applications.
基金supported by the National Natural Science Foundation of China(Nos.22175043 and 52162021)Guangxi Science and Technology Plan Project(No.Guike AA23073018)supported by the high-performance computing platform of Guangxi University。
文摘Zero-dimensional metal halides are of unique structures and tunable photoluminescence properties,showing great potential applications such as light-emitting diodes(LEDs)and sensing.Herein,we successfully synthesized Cu^(+)doped(MA)_(2)ZnCl_(4)metal halides by a slow evaporation solvent method.The introduction of Cu^(+)results in sky-blue self-trapped exciton emission in(MA)_(2)ZnCl_(4) at 486 nm at room temperature,and a photoluminescence quantum yield is as high as 54.9%.Interestingly,at low temperatures,Cu^(+)-doped(MA)_(2)ZnCl_(4) exhibits two emission peaks located at 482 and 605 nm,respectively.This temperaturedependent dual emission indicates two excited state structures that exist on the triplet excited-state potential energy surface.In addition,the temperature sensor we fitted has good performance(Sr=1.65%·K^(−1)),which is the first attempt in Cu^(+) doped Znbased metal halides.Our work enriches the family of sky-blue metal halides and provides a promising strategy for building skyblue LEDs.
基金supported by the National Natural Science Foundation of China (22175181, 92061202, U22A20387)the Fujian Science and Technology Project (2020L3022)。
文摘Developing highly sensitive optical thermometers is of great significance due to their capability to enable remote and non-contact temperature measurements, rendering them highly applicable in diverse and harsh environments. Herein we report a temperature-dependent phosphor of 0D metal halide hybrid by incorporating Bi^(3+)into the(MePPh_(3))_(2)ZnCl_(4) matrix. Through Bi^(3+)doping,the initially non-luminescent(MePPh_(3))_(2) ZnCl_(4) matrix exhibits a deep-blue emission centered at 453 nm, with a photoluminescence quantum yield(PLQY) of 5.71% and a Stokes shift of 75 nm at room temperature. Experimental characterization demonstrates that exciton-like luminescence of Bi^(3+)is mainly responsible for the blue emission. Single crystals of Bi^(3+)-doped(MePPh_(3))_(2)ZnCl_(4) show an unusual correlation between photoluminescence(PL) lifetime and temperature. Particularly, the dependence of luminescence lifetime on temperature is most remarkable in the temperature range of 80 to 100 K with an exceptional sensitivity up to 0.09 K^(-1), representing one of the best levels for thermometry based on PL decay lifetime. Our work not only provides a viable strategy for designing a novel, environmentally friendly, and stable blue emitter, but also paves the way for precise thermometric application at low temperature.
基金support from the National Basic Research Program of China(973 Program)(2009CB930601)the National Natural Science Foundation of China(20904024)+2 种基金the Doctoral Fund of Ministry of Education of China(20093223120004)the NUPT Scientific Foundation(NY210016)Scientific and Technological Innovation Teams of Jiangsu Province Education Committee,China (TJ209035)
文摘Hyperbranched polymer structures represent a class of high-functionality building blocks with excellent three-dimensional topology for the construction of highly substituted conjugated polymers.In this contribution,an efficient microwave synthesis protocol toward the synthesis of conjugated hyperbranched polymers is presented.A novel series of soluble hyperbranched polyfluorenes (PTF1-PTF3) incorporating triazatruxene moiety as the branch units with various branching degrees have thus been successfully constructed with good yields and high molecular weight via a facile "A2+B2+C3" approach.The structures of the hyperbranched polymers were confirmed by NMR and GPC.Their thermal,optical,and electrochemical properties of the hyperbranched polymers were also investigated.The results showed that introduction of triazatruxene units into the hyperbranched structure endowed the polymer with good thermal stability and highly amorphous properties.Photophysical investigation of PTFx revealed strong blue emission in both solution and solid states.Hyperbranched polymers with higher degree of branching and proper content of linear fluorene units exhibited better photophysical properties in terms of narrow emission spectra and relatively high quantum efficiency as well as improved thermal spectral stability.The triazatruxene branching unit also played a role in raising the HOMO energy levels relative to those of polyfluorenes that would help to improve the charge injection and transport properties.The incorporation of triazatruxene unit into hyperbranched polymers has thus explored an effective avenue for constructing optoelectronic polymers with improved functional characteristics.
基金This work was supported by the National Natural Science Foundation of China(Nos.52073282,52122309,21975247,51833009,52261135541)the CAS-Croucher Funding Scheme for Joint Laboratories,the Open Project of the State Key Laboratory of Supramolecular Structure and Materials,China(No.sklssm2023019)the Start-up Scientific Research Foundation from Hainan University,China[No.KYQD(ZR)22174]。
文摘Three polymer hosts(namely PNB-tBuCz,PNB-Ac,PNB-TAc)containing non-conjugated polynorbornene(PNB)backbone and hole-transporting arylamine segments(carbazole,acridan and dendritic teracridan)in side chains are developed for solution-processed narrowband blue organic light-emitting diodes(OLEDs).It is found that the non-conjugated polynorbornenes can keep high triplet energy(ET)levels in range of 3.12-3.20 eV by interrupting the conjugation of repeating units,making them capable as host materials for blue emitters.Meanwhile,by increasing the electron-donating capability of side chain arylamine from carbazole to acridan and dendritic teracridan,the highest occupied molecular orbital(HOMO)levels for the polymer hosts are elevated from-5.50 eV to-5.11 eV,beneficial for reducing the hole injection barrier from anode to emissive layer.As a result,solution-processed OLEDs employing polynorbornenes with dendritic teracridan side chain(PNB-TAc)as host and boron,selenium,nitrogen-containing multiple resonance thermally activated delayed fluorescence emitter as dopant reveal efficient narrowband blue electroluminescence with emission peak at 474 nm,full-width at half maximum of 30 nm,together with maximum external quantum efficiency of 20.2%,representing the state-of-the-art device efficiency for solution-processed OLEDs with narrowband blue emission.
