Ternary ZnSeTe quantum dots(QDs)are recognized as promising eco-friendly emitters for blue quantumdot light-emitting diodes(QD-LEDs)and are capable of extending their emission range to green or even red light.Although...Ternary ZnSeTe quantum dots(QDs)are recognized as promising eco-friendly emitters for blue quantumdot light-emitting diodes(QD-LEDs)and are capable of extending their emission range to green or even red light.Although extensive investigations have enabled significant advances in the external quantum efficiency of blue ZnSeTe QD-LEDs,unfortunately,the lack of effective defect passivation strategies for green and red ZnSeTe QDs poses difficulties in improving device performance,thereby impeding their development.Here,we propose to enhance the luminescence performance of green ZnSeTe devices by inserting an ultrathin ZnSeS interlayer to fabricate efficient QDs.This strategy enables us to achieve gradient thick-shell QD structures,thereby alleviating lattice mismatch at the shell-shell interface and passivating surface defects.These improvements result in enhanced quantum efficiency,improved optical stability,and elevated band position.These combined features enhance exciton recombination and promote charge injection balance,leading to a record-breaking external quantum efficiency of 20.6%and a high brightness of 106,054 cd m-2,accompanied by an improved operational stability.展开更多
The production of high-quality eco-friendly quantum dots(QDs)is challenging because of the efficient yet elusive nonradiative recombination within.This study examined the effects of cooling engineering on regulating t...The production of high-quality eco-friendly quantum dots(QDs)is challenging because of the efficient yet elusive nonradiative recombination within.This study examined the effects of cooling engineering on regulating the excited states to realize high-quality ZnSeTe core-shell QDs.The presence of ultrafast hot-carrier trapping and band-edge carrier trapping is responsible for the poor emission efficiency in ZnSeTe QDs.The above processes can be suppressed simultaneously by engineering the cooling process,and the underlying mechanisms are interrogated by combined electronic and spectroscopic characterization.The engineered ZnSeTe QDs exhibited record-high efficiency(>90%)and stability that were comparable to those of the canonical CdSe QDs.Leveraging on the achievement,the ZnSeTe QD-based white light-emitting diodes(WLEDs)showed excellent optical performance,including a high color-rendering index of 80 and an appropriate correlated color temperature of 7391 K.Furthermore,the WLEDs could serve as light sources in ecofriendly visible light communication.These results highlight the feasibility of eco-friendly QDs for practical applications without environmental hazards.展开更多
Zinc chalcogenide which includes zinc selenide,zinc sulphide,zinc telluride and mixed crystals of these shows a great potential as an optoelectronic device material. Zinc selenotelluride is a suitable material for vis...Zinc chalcogenide which includes zinc selenide,zinc sulphide,zinc telluride and mixed crystals of these shows a great potential as an optoelectronic device material. Zinc selenotelluride is a suitable material for visible light emitting devices which are expected to cover the spectral range from yellow to blue. In our present study the composition controlled ZnSe1-xTex films with different Te content x = 0,0.2,0.4,0.6,0.8 and 1.0 were deposited by electron beam (EB) evaporation technique. GaAs films were deposited by vacuum evaporation route on indium tin oxide (ITO) substrates which were used as base for depositing the ZnSe1-xTex film. The band-gap energy change in the entire composition range was determined at room temperature by photoluminescence (PL) spectroscopy. The peak observed at about 2.56 eV shows the effect of solid solution formation between ZnSe and ZnTe which modifies the lattice and consequently the band edge emission characteristics. The heterostructures showed three peaks in the visible region of white light spectrum.展开更多
基金the financial support from the National Natural Science Foundation of China(62204077 and U22A2072)the China Postdoctoral Science Foundation(2022M711030)+1 种基金the National Key R&D Program of China(2023YFE0205000)Zhongyuan High Level Talents Special Support Plan(244200510009)。
文摘Ternary ZnSeTe quantum dots(QDs)are recognized as promising eco-friendly emitters for blue quantumdot light-emitting diodes(QD-LEDs)and are capable of extending their emission range to green or even red light.Although extensive investigations have enabled significant advances in the external quantum efficiency of blue ZnSeTe QD-LEDs,unfortunately,the lack of effective defect passivation strategies for green and red ZnSeTe QDs poses difficulties in improving device performance,thereby impeding their development.Here,we propose to enhance the luminescence performance of green ZnSeTe devices by inserting an ultrathin ZnSeS interlayer to fabricate efficient QDs.This strategy enables us to achieve gradient thick-shell QD structures,thereby alleviating lattice mismatch at the shell-shell interface and passivating surface defects.These improvements result in enhanced quantum efficiency,improved optical stability,and elevated band position.These combined features enhance exciton recombination and promote charge injection balance,leading to a record-breaking external quantum efficiency of 20.6%and a high brightness of 106,054 cd m-2,accompanied by an improved operational stability.
文摘设计了(CdZnTe,ZnSeTe)/ZnTe复合量子阱结构,并用吸收光谱、室温光致发光谱和飞秒脉冲抽运-探测方法研究了该复合结构中的激子隧穿过程.分别测量了该结构中CdZnTe/ZnTe量子阱层和ZnSeTe/ZnTe量子阱层中激子衰减时间.观察到从CdZnTe/ZnTe量子阱层向ZnSeTe/ZnTe量子阱层的快速激子隧穿,隧穿时间为5.5 ps.
基金supported by the National Natural Science Foundation of China(11904172)Natural Science Foundation of Jiangsu Province(BK20190446)support of the start-up funding from Nanjing University of Science and Technology。
文摘The production of high-quality eco-friendly quantum dots(QDs)is challenging because of the efficient yet elusive nonradiative recombination within.This study examined the effects of cooling engineering on regulating the excited states to realize high-quality ZnSeTe core-shell QDs.The presence of ultrafast hot-carrier trapping and band-edge carrier trapping is responsible for the poor emission efficiency in ZnSeTe QDs.The above processes can be suppressed simultaneously by engineering the cooling process,and the underlying mechanisms are interrogated by combined electronic and spectroscopic characterization.The engineered ZnSeTe QDs exhibited record-high efficiency(>90%)and stability that were comparable to those of the canonical CdSe QDs.Leveraging on the achievement,the ZnSeTe QD-based white light-emitting diodes(WLEDs)showed excellent optical performance,including a high color-rendering index of 80 and an appropriate correlated color temperature of 7391 K.Furthermore,the WLEDs could serve as light sources in ecofriendly visible light communication.These results highlight the feasibility of eco-friendly QDs for practical applications without environmental hazards.
文摘Zinc chalcogenide which includes zinc selenide,zinc sulphide,zinc telluride and mixed crystals of these shows a great potential as an optoelectronic device material. Zinc selenotelluride is a suitable material for visible light emitting devices which are expected to cover the spectral range from yellow to blue. In our present study the composition controlled ZnSe1-xTex films with different Te content x = 0,0.2,0.4,0.6,0.8 and 1.0 were deposited by electron beam (EB) evaporation technique. GaAs films were deposited by vacuum evaporation route on indium tin oxide (ITO) substrates which were used as base for depositing the ZnSe1-xTex film. The band-gap energy change in the entire composition range was determined at room temperature by photoluminescence (PL) spectroscopy. The peak observed at about 2.56 eV shows the effect of solid solution formation between ZnSe and ZnTe which modifies the lattice and consequently the band edge emission characteristics. The heterostructures showed three peaks in the visible region of white light spectrum.
