Solution-processed quantum dot light-emitting diodes(QLEDs)hold great potential as competitive candidates for display and lighting applications.However,the serious energy disorder between the quantum dots(QDs)and hole...Solution-processed quantum dot light-emitting diodes(QLEDs)hold great potential as competitive candidates for display and lighting applications.However,the serious energy disorder between the quantum dots(QDs)and hole transport layer(HTL)makes it challenging to achieve high-performance devices at lower voltage ranges.Here,we introduce"giant"fully alloy CdZnSe/ZnSeS core/shell QDs(size~19 nm)as the emitting layer to build high-efficient and stable QLEDs.The synthesized CdZnSe-based QDs reveal a decreased ground-state band splitting,shallow valence band maximum,and improved quasi-Fermi level splitting,which effectively flatten the energy landscape between the QD layer and hole transport layer.The higher electron concentration and accelerated hole injection significantly promote the carrier radiative recombination dynamics.Consequently,CdZnSe-based device exhibits a high power conversion efficiency(PCE)of 27.3%and an ultra-low efficiency roll-off,with a high external quantum efficiency(EQE)exceeding 25%over a wide range of low driving voltages(1.8-3.0V)and low heat generation.The record-high luminance levels of 1,400 and 8,600 cd m^(-2)are achieved at bandgap voltages of 100%and 120%,respectively.Meanwhile,These LEDs show an unprecedented operation lifetime T_(95)(time for the luminance to decrease to 95%)of 72,968 h at 1,000 cd m^(-2).Our work points to a novel path to flatten energy landscape at the QD-related interface for solution-processedphotoelectronicdevices.展开更多
Quantum dot(QD)light-emitting diodes(QD-LEDs),known for their high color quality and cost-effectiveness,have emerged as promising candidates for next-generation display and lighting technologies.However,suboptimal ele...Quantum dot(QD)light-emitting diodes(QD-LEDs),known for their high color quality and cost-effectiveness,have emerged as promising candidates for next-generation display and lighting technologies.However,suboptimal electron concentration resulting from defects at the QD core/shell interface limits the brightness and operational lifetime,thereby hindering the commercialization of QD-LEDs.Here,we present high-brightness and stable LEDs based on oleylamine(OAM)-assisted green ZnCdSe/ZnSeS/ZnS QDs.OAM treatment alleviates the dangling bonds on the QD core surfaces and eliminates defect states at the core/shell interface,thereby suppressing exciton quenching at the QD-electron transport layer(ETL)interface.Our findings demonstrate that QD-LEDs with OAM facilitate electron transport from the ETL to the QDs,increasing electron concentration,and reducing the hole injection barrier,ultimately accelerating carrier radiative recombination.Consequently,the green QD-LEDs exhibit a luminance of 1,105,500 cd/m^(2)and a record-long T_(95)operational lifetime of exceeding 24,800 h at 1000 cd/m^(2).Our work provides an alternative pathway for the full-color and high-definition display application of high-performance QD-LEDs.展开更多
Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be...Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be demonstrated.Here,we develop a nebulization method to fabricate colloidal quantum dots self-assembled microspheres,which can be levitated by photophoresis provided by continuous wave lasers and photoexcited by pulsed lasers.These levitated microspheres can serve as high-quality gain media and whispering gallery mode cavities simultaneously,allowing us to demonstrate the levitated solidstate laser for the first time.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.22205054,U22A2072,61922028,22175056,and 22479041)Zhongyuan High-Level Talents Special Support Plan(No.244200510009)+1 种基金the National Key R&D Program of China(Grant No.2023YFE0205000)Postdoctoral Research Grant in Henan Province(No.202103041).
文摘Solution-processed quantum dot light-emitting diodes(QLEDs)hold great potential as competitive candidates for display and lighting applications.However,the serious energy disorder between the quantum dots(QDs)and hole transport layer(HTL)makes it challenging to achieve high-performance devices at lower voltage ranges.Here,we introduce"giant"fully alloy CdZnSe/ZnSeS core/shell QDs(size~19 nm)as the emitting layer to build high-efficient and stable QLEDs.The synthesized CdZnSe-based QDs reveal a decreased ground-state band splitting,shallow valence band maximum,and improved quasi-Fermi level splitting,which effectively flatten the energy landscape between the QD layer and hole transport layer.The higher electron concentration and accelerated hole injection significantly promote the carrier radiative recombination dynamics.Consequently,CdZnSe-based device exhibits a high power conversion efficiency(PCE)of 27.3%and an ultra-low efficiency roll-off,with a high external quantum efficiency(EQE)exceeding 25%over a wide range of low driving voltages(1.8-3.0V)and low heat generation.The record-high luminance levels of 1,400 and 8,600 cd m^(-2)are achieved at bandgap voltages of 100%and 120%,respectively.Meanwhile,These LEDs show an unprecedented operation lifetime T_(95)(time for the luminance to decrease to 95%)of 72,968 h at 1,000 cd m^(-2).Our work points to a novel path to flatten energy landscape at the QD-related interface for solution-processedphotoelectronicdevices.
基金supported by the National Key R&D Program of China(No.2023YFE0205000)the National Natural Science Foundation of China(Nos.U22A2072,22205054, 61922028),Technological Innovation 2030-Major Projects(No.2024ZD0604000)Zhongyuan High Level Talents Special Support Plan(No.244200510009)。
文摘Quantum dot(QD)light-emitting diodes(QD-LEDs),known for their high color quality and cost-effectiveness,have emerged as promising candidates for next-generation display and lighting technologies.However,suboptimal electron concentration resulting from defects at the QD core/shell interface limits the brightness and operational lifetime,thereby hindering the commercialization of QD-LEDs.Here,we present high-brightness and stable LEDs based on oleylamine(OAM)-assisted green ZnCdSe/ZnSeS/ZnS QDs.OAM treatment alleviates the dangling bonds on the QD core surfaces and eliminates defect states at the core/shell interface,thereby suppressing exciton quenching at the QD-electron transport layer(ETL)interface.Our findings demonstrate that QD-LEDs with OAM facilitate electron transport from the ETL to the QDs,increasing electron concentration,and reducing the hole injection barrier,ultimately accelerating carrier radiative recombination.Consequently,the green QD-LEDs exhibit a luminance of 1,105,500 cd/m^(2)and a record-long T_(95)operational lifetime of exceeding 24,800 h at 1000 cd/m^(2).Our work provides an alternative pathway for the full-color and high-definition display application of high-performance QD-LEDs.
基金supported by the National Natural Science Foundation of China(No.52272167)the Innovation Program for Quantum Science and Technology(No.2021ZD0301603).carried out at the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be demonstrated.Here,we develop a nebulization method to fabricate colloidal quantum dots self-assembled microspheres,which can be levitated by photophoresis provided by continuous wave lasers and photoexcited by pulsed lasers.These levitated microspheres can serve as high-quality gain media and whispering gallery mode cavities simultaneously,allowing us to demonstrate the levitated solidstate laser for the first time.
