The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs b...The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs based on M-EMLs separated by polyethyleneimine ethoxylated(PEIE)layer with different stacking sequences of blue(B),green(G),and red(R)QDs layer were used to intuitively explore the injection,transportation and recombination processes of the charge carriers in QLEDs by using the time-resolved electroluminescence(TrEL)spectra.From the TrEL spectra mea-surements,green and red emissions were obtained first in the QLEDs with the EMLs sequences of G/PEIE/B/PEIE/R and B/PEIE/R/PEIE/G along the direction of light emission,respectively.While the QLEDs adopt EMLs sequences of B/PEIE/G/PEIE/R,the blue,green and red emissions were obtained nearly at the same time.The above phenomenon can be attributed to different charge carrier transmission and radiation recombination process in the EMLs due to different valence band offsets and conduction band offsets between R-,G-and B-QDs by using different sequences of EMLs.White emission with coordi-nates of(0.31,0.31)and correlated color temperature(CCT)of 5916 K was obtained in the QLEDs with the EMLs se-quences of B/PEIE/G/PEIE/R,which can be attributed to the relative uniform emission of B-,G-and R-QDs due to the effec-tive injection and radiation recombination of charge carriers in each of the EMLs.The above results have great significance for further understanding and improving the performance of QLEDs with M-EMLs.展开更多
Developing single-pixel color-tunable electroluminescence technology represents a practical approach to circumvent current limitations in pixel processing and longevity.However,existing single-pixel color-tunable quan...Developing single-pixel color-tunable electroluminescence technology represents a practical approach to circumvent current limitations in pixel processing and longevity.However,existing single-pixel color-tunable quantum dot light-emitting diodes(QLEDs)devices predominantly employ complex tandem structures.Herein,we demonstrate single-layer color-tunable QLEDs by the real-time interface exciplex modulation with AgInZnS(AIZS)quantum dots(QDs).The dynamically color-tunable QLEDs based on green-and red-emitting AIZS QDs exhibit broad spectral coverage,spanning from green to blue,red to yellow,as well as standard white emission.The fabricated devices achieve a leading maximum external quantum efficiency of 5%for quaternary alloy AIZS-based QLEDs.Furthermore,we successfully demonstrate patterned and large-area QLEDs,systematically confirming their significant potential for application in full-color display and lighting technologies.展开更多
In the aforementioned article,on page 5,the curves of current density and luminance with voltage variation for the device without and with ZnMy_(2)in figures 3(c)and(e)are incorrect.The voltage of the device without Z...In the aforementioned article,on page 5,the curves of current density and luminance with voltage variation for the device without and with ZnMy_(2)in figures 3(c)and(e)are incorrect.The voltage of the device without ZnMy_(2)should be 2.1 V not 2.2 V in the previous version.The larger current density should be around 18%,not 20%in the previous version.The luminance of the QLED based on ZnMy_(2)-treated QDs is improved by 50%compared to the device without ZnMy_(2)(116944 cd m^(−2)),not 67%and 105127 cd m^(−2)in the previous version.The the maximum EQE and current efficiency for the QLEDs without ZnMy_(2)are 9.19%and 36.90 cd A^(−1),respectively,not 9.22%and 36.72 cd A^(−1)in the previous version.Corrected version of figures 3(c)and(e)are shown below.展开更多
Microdisplay panels are critical components for metaverse technology.Aiming to achieve high-resolution and full-color microdisplay,we report the photolithographic fabrication of color-converted Micro-quantum dot light...Microdisplay panels are critical components for metaverse technology.Aiming to achieve high-resolution and full-color microdisplay,we report the photolithographic fabrication of color-converted Micro-quantum dot light emitting diodes(QLED)panel by combining blue Micro-QLED electroluminescence(EL)device and red-green quantum dot color converter(QDCC).Pre-patterned templates were firstly photolithographically fabricated and then applied as substrate to fabricate patterned blue Micro-QLED device,achieving an ultra-high pixel resolution up to 6350 pixels per inch(pixel size ranging from 20μm×20μm to 2μm×2μm).Notably,the patterned blue devices achieve a peak external quantum efficiency(EQE)of 7.8%and a maximum brightness of 39,472 cd m^(−2).The patterned red devices achieve a peak EQE of 18%and a maximum brightness of 103,022 cd m^(−2).By integrating a dual-color red and green QDCC arrays on the top of the blue Micro-QLED,a prototype full-color Micro-QLED panel was fabricated,achieving a resolution up to 1184 pixels per inch with a peak EQE 4.8%,and a maximum brightness of 10065 cd m^(−2).The photolithographic fabrication of color-converted Micro-QLED provides an easy-operated method for achieving cost-effective microdisplay panels.展开更多
Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum...Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum dots-based light-emitting diodes(QLEDs)due to its suitable energy level and high mobility.However,there are still many challenging issues in inkjet-printed QLED devices when using TFB as HTL.TFB normally suffers from the interlayer mixing and erosion,and low surface energy against the good film formation.Here,a novel environment-friendly binary solvent system was established for formulating quantum dot(QD)inks,which is based on mixing halogen-free alkane solvents of decalin and n-tridecane.The optimum volume ratio for the mixture of decalin and n-tridecane was found to be 7:3,at which a stable ink jetting flow and coffee-ring free QD films could be formed.To research the influence of substrate surface on the formation of inkjet-printed QD films,TFB was annealed at different temperatures,and the optimum annealing temperature was found to enable high quality inkjet-printed QD film.Inkjet-printed red QLED was ultimately manufactured.A maximum 18.3%of external quantum efficiency(EQE)was achieved,reaching 93%of the spin-coated QLED,which is the best reported high efficiency inkjet-printed red QLEDs to date.In addition,the inkjet-printed QLED achieved similar T75 operational lifetime(27 h)as compared to the spin-coated reference QLED(28 h)at 2,000 cd·m−2.This work demonstrated that the novel orthogonal halogen-free alkane co-solvents can improve the interfacial contact and facilitate high-performance inkjet printing QLEDs with high EQE and stability.展开更多
In blue quantum dot light emitting diodes(QLEDs),electron injection is insufficient,which would degrade device efficiency and stability.Herein,we employ chlorine passivated ZnO nanoparticles as electron transport laye...In blue quantum dot light emitting diodes(QLEDs),electron injection is insufficient,which would degrade device efficiency and stability.Herein,we employ chlorine passivated ZnO nanoparticles as electron transport layer to facilitate electron injection into QDs effectively.Moreover,it suppresses exciton quenching at the QD/ZnO interface by blocking charge transfer channel.As a result,the maximum external quantum efficiency of blue QLED was increased from 2.55%to 4.60%,and the operation lifetime of blue QLED was nearly 4 times longer than that of the control device.Our work indicates that election injection plays an important role in blue QLED efficiency and stability.展开更多
文摘The charge carrier transport and recombination dynamics in the quantum dots-based light-emitting diodes(QLEDs)featuring multiple emitting layers(M-EMLs)has a great impact on the device performance.In this work,QLEDs based on M-EMLs separated by polyethyleneimine ethoxylated(PEIE)layer with different stacking sequences of blue(B),green(G),and red(R)QDs layer were used to intuitively explore the injection,transportation and recombination processes of the charge carriers in QLEDs by using the time-resolved electroluminescence(TrEL)spectra.From the TrEL spectra mea-surements,green and red emissions were obtained first in the QLEDs with the EMLs sequences of G/PEIE/B/PEIE/R and B/PEIE/R/PEIE/G along the direction of light emission,respectively.While the QLEDs adopt EMLs sequences of B/PEIE/G/PEIE/R,the blue,green and red emissions were obtained nearly at the same time.The above phenomenon can be attributed to different charge carrier transmission and radiation recombination process in the EMLs due to different valence band offsets and conduction band offsets between R-,G-and B-QDs by using different sequences of EMLs.White emission with coordi-nates of(0.31,0.31)and correlated color temperature(CCT)of 5916 K was obtained in the QLEDs with the EMLs se-quences of B/PEIE/G/PEIE/R,which can be attributed to the relative uniform emission of B-,G-and R-QDs due to the effec-tive injection and radiation recombination of charge carriers in each of the EMLs.The above results have great significance for further understanding and improving the performance of QLEDs with M-EMLs.
基金supported by the National Key Research and Development Program of China(2024YFB3612400 and 2024YFA1210002)the National Natural Science Foundation of China(62574111,62204120,52533012,U24A20286,52131304,and 62261160392)+1 种基金International Cooperation Program of Jiangsu Province of China(BZ2024038)the Fundamental Research Funds for the Central Universities(30925010415).
文摘Developing single-pixel color-tunable electroluminescence technology represents a practical approach to circumvent current limitations in pixel processing and longevity.However,existing single-pixel color-tunable quantum dot light-emitting diodes(QLEDs)devices predominantly employ complex tandem structures.Herein,we demonstrate single-layer color-tunable QLEDs by the real-time interface exciplex modulation with AgInZnS(AIZS)quantum dots(QDs).The dynamically color-tunable QLEDs based on green-and red-emitting AIZS QDs exhibit broad spectral coverage,spanning from green to blue,red to yellow,as well as standard white emission.The fabricated devices achieve a leading maximum external quantum efficiency of 5%for quaternary alloy AIZS-based QLEDs.Furthermore,we successfully demonstrate patterned and large-area QLEDs,systematically confirming their significant potential for application in full-color display and lighting technologies.
文摘In the aforementioned article,on page 5,the curves of current density and luminance with voltage variation for the device without and with ZnMy_(2)in figures 3(c)and(e)are incorrect.The voltage of the device without ZnMy_(2)should be 2.1 V not 2.2 V in the previous version.The larger current density should be around 18%,not 20%in the previous version.The luminance of the QLED based on ZnMy_(2)-treated QDs is improved by 50%compared to the device without ZnMy_(2)(116944 cd m^(−2)),not 67%and 105127 cd m^(−2)in the previous version.The the maximum EQE and current efficiency for the QLEDs without ZnMy_(2)are 9.19%and 36.90 cd A^(−1),respectively,not 9.22%and 36.72 cd A^(−1)in the previous version.Corrected version of figures 3(c)and(e)are shown below.
基金supported by the National Natural Science Foundation of China(U23A20683,H.Z.)the Natural Science Foundation of Beijing Municipality(No.Z210018)+2 种基金Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science under Park No.Z231100006023018the National Natural Science Foundation of China(62422501)the National Natural Science Foundation of China(No.52203321)。
文摘Microdisplay panels are critical components for metaverse technology.Aiming to achieve high-resolution and full-color microdisplay,we report the photolithographic fabrication of color-converted Micro-quantum dot light emitting diodes(QLED)panel by combining blue Micro-QLED electroluminescence(EL)device and red-green quantum dot color converter(QDCC).Pre-patterned templates were firstly photolithographically fabricated and then applied as substrate to fabricate patterned blue Micro-QLED device,achieving an ultra-high pixel resolution up to 6350 pixels per inch(pixel size ranging from 20μm×20μm to 2μm×2μm).Notably,the patterned blue devices achieve a peak external quantum efficiency(EQE)of 7.8%and a maximum brightness of 39,472 cd m^(−2).The patterned red devices achieve a peak EQE of 18%and a maximum brightness of 103,022 cd m^(−2).By integrating a dual-color red and green QDCC arrays on the top of the blue Micro-QLED,a prototype full-color Micro-QLED panel was fabricated,achieving a resolution up to 1184 pixels per inch with a peak EQE 4.8%,and a maximum brightness of 10065 cd m^(−2).The photolithographic fabrication of color-converted Micro-QLED provides an easy-operated method for achieving cost-effective microdisplay panels.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFB0401600)the National Natural Science Foundation of China(No.U1605244)China Postdoctoral Science Foundation(No.2020M681726).
文摘Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4′-(N-(4-butylphenyl))](TFB),one of the most popular and widely used hole-transport layer(HTL)materials,has been successfully applied in high performance spin-coated quantum dots-based light-emitting diodes(QLEDs)due to its suitable energy level and high mobility.However,there are still many challenging issues in inkjet-printed QLED devices when using TFB as HTL.TFB normally suffers from the interlayer mixing and erosion,and low surface energy against the good film formation.Here,a novel environment-friendly binary solvent system was established for formulating quantum dot(QD)inks,which is based on mixing halogen-free alkane solvents of decalin and n-tridecane.The optimum volume ratio for the mixture of decalin and n-tridecane was found to be 7:3,at which a stable ink jetting flow and coffee-ring free QD films could be formed.To research the influence of substrate surface on the formation of inkjet-printed QD films,TFB was annealed at different temperatures,and the optimum annealing temperature was found to enable high quality inkjet-printed QD film.Inkjet-printed red QLED was ultimately manufactured.A maximum 18.3%of external quantum efficiency(EQE)was achieved,reaching 93%of the spin-coated QLED,which is the best reported high efficiency inkjet-printed red QLEDs to date.In addition,the inkjet-printed QLED achieved similar T75 operational lifetime(27 h)as compared to the spin-coated reference QLED(28 h)at 2,000 cd·m−2.This work demonstrated that the novel orthogonal halogen-free alkane co-solvents can improve the interfacial contact and facilitate high-performance inkjet printing QLEDs with high EQE and stability.
基金Project supported by the National Key R&D Program of China(Grant Nos.2016YFB0401702 and 2017YFE0120400)the National Natural Science Foundation of China(Grant Nos.62005114,62005115,and 61875082)+5 种基金Key-Area Research and Development Program of Guangdong Province,China(Grant Nos.2019B010925001 and 2019B010924001)Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting(Grant No.2017KSYS007)Natural Science Foundation of Guangdong Province,China(Grant No.2017B030306010)Guangdong Basic and Applied Basic Research Foundation,China(Grant No.2019A1515110437)Shenzhen Peacock Team Project(Grant No.KQTD2016030111203005)High Level University Fund of Guangdong Province,China(Grant No.G02236004).
文摘In blue quantum dot light emitting diodes(QLEDs),electron injection is insufficient,which would degrade device efficiency and stability.Herein,we employ chlorine passivated ZnO nanoparticles as electron transport layer to facilitate electron injection into QDs effectively.Moreover,it suppresses exciton quenching at the QD/ZnO interface by blocking charge transfer channel.As a result,the maximum external quantum efficiency of blue QLED was increased from 2.55%to 4.60%,and the operation lifetime of blue QLED was nearly 4 times longer than that of the control device.Our work indicates that election injection plays an important role in blue QLED efficiency and stability.
