ZnS：Cu, Eu nanocrystals with an average diameter of 80 nm are synthesized using a hydrothermal approach at 200 ℃. The photoluminescence （PL） properties of the ZnS：Cu, Eu nanocrystals before and after annealing, ...ZnS：Cu, Eu nanocrystals with an average diameter of 80 nm are synthesized using a hydrothermal approach at 200 ℃. The photoluminescence （PL） properties of the ZnS：Cu, Eu nanocrystals before and after annealing, as well as the doping form of Eu, are studied. The as-synthesized samples are characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma-atomic emission spectrometry, and the excitation and emission spectra （PL）. The results show that both Cu and Eu are indeed incorporated into the ZnS matrix. Compared with the PL spectrum of the Cu mono-doped sample, the PL emission intensity of the Cu and Eu-codoped sample increases and a peak appears at 516 nm, indicating that Eu3＋ ions, which act as an impurity compensator and activator, are incorporated into the ZnS matrix, forming a donor level. Compared with the unannealed sample, the annealed one has an increased PL emission intensity and the peak position has a blue shift of 56 nm from 516 nm to 460 nm, which means that Eu3＋ ions reduce to Eu2＋ ions, thereby leading to the appearance of Eu2＋ characteristic emission and generating effective host-to-Eu2＋ energy transfer. The results indicate the potential applications of ZnS：Cu, Eu nanoparticles in optoelectronic devices.展开更多
Electroluminescent composites have considerable potential for applications in photoelectric display,electric field measurement and other fields due to their advantages of simple preparation and uniform luminescence.Ho...Electroluminescent composites have considerable potential for applications in photoelectric display,electric field measurement and other fields due to their advantages of simple preparation and uniform luminescence.However,high voltage required by the operation of electroluminescent composites hinders their applications in the electric domain,and research on the relationship between electroluminescence principle of composites and filler intrinsic attributes is insufficient.In this paper,the effects of electric field strength,filler mass fraction and voltage frequency on the electroluminescence intensity of ZnS:Cu/epoxy composites are studied,which are majorly used as the luminescent layer of electroluminescent devices.To enhance the electroluminescence intensity of composites,high-temperature sintered BaTiO_(3)and zinc oxide whiskers(ZnOw)particles are introduced in the base matrix.The finite element method is applied to verify that the matrix of high dielectric constant is in favour of improving the electroluminescence intensity of composites.The band structure of the ZnS:Cu particle is calculated based on the density functional theory+U method to analyse the intrinsic relationship between electroluminescence and particle electronic structure.This paper provides a basis for the research of high electroluminescence intensity devices and will be conducive to better understanding on the relationship between electroluminescence principle and filler intrinsic attributes.展开更多
ZnS ∶Cu nanoparticles were prepared by using microemulsion method at room temperature. The size of the particles is 2-8 nm by transmission electron microscopy (TEM) and dynamic light scattering (DLS) technique. X-ray...ZnS ∶Cu nanoparticles were prepared by using microemulsion method at room temperature. The size of the particles is 2-8 nm by transmission electron microscopy (TEM) and dynamic light scattering (DLS) technique. X-ray diffraction analysis shows that the particles are cubic crystal structure, the same structure as the bulk ZnS materials. Ultraviolet absorption demonstrates an increased bandgap due to quantum confinement effect. Photoluminescence spectrum shows there is a single green emission band at 482 nm.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.10374011)the Doctoral Fund of Dalian Nationalities University,China(Grant No.20116201)
文摘ZnS：Cu, Eu nanocrystals with an average diameter of 80 nm are synthesized using a hydrothermal approach at 200 ℃. The photoluminescence （PL） properties of the ZnS：Cu, Eu nanocrystals before and after annealing, as well as the doping form of Eu, are studied. The as-synthesized samples are characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma-atomic emission spectrometry, and the excitation and emission spectra （PL）. The results show that both Cu and Eu are indeed incorporated into the ZnS matrix. Compared with the PL spectrum of the Cu mono-doped sample, the PL emission intensity of the Cu and Eu-codoped sample increases and a peak appears at 516 nm, indicating that Eu3＋ ions, which act as an impurity compensator and activator, are incorporated into the ZnS matrix, forming a donor level. Compared with the unannealed sample, the annealed one has an increased PL emission intensity and the peak position has a blue shift of 56 nm from 516 nm to 460 nm, which means that Eu3＋ ions reduce to Eu2＋ ions, thereby leading to the appearance of Eu2＋ characteristic emission and generating effective host-to-Eu2＋ energy transfer. The results indicate the potential applications of ZnS：Cu, Eu nanoparticles in optoelectronic devices.
基金National Natural Science Foundation of China,Grant/Award Number:51877082Science and Technology Project of State Grid Corporation of China,Grant/Award Number:7000-202158440A-0-0-00。
文摘Electroluminescent composites have considerable potential for applications in photoelectric display,electric field measurement and other fields due to their advantages of simple preparation and uniform luminescence.However,high voltage required by the operation of electroluminescent composites hinders their applications in the electric domain,and research on the relationship between electroluminescence principle of composites and filler intrinsic attributes is insufficient.In this paper,the effects of electric field strength,filler mass fraction and voltage frequency on the electroluminescence intensity of ZnS:Cu/epoxy composites are studied,which are majorly used as the luminescent layer of electroluminescent devices.To enhance the electroluminescence intensity of composites,high-temperature sintered BaTiO_(3)and zinc oxide whiskers(ZnOw)particles are introduced in the base matrix.The finite element method is applied to verify that the matrix of high dielectric constant is in favour of improving the electroluminescence intensity of composites.The band structure of the ZnS:Cu particle is calculated based on the density functional theory+U method to analyse the intrinsic relationship between electroluminescence and particle electronic structure.This paper provides a basis for the research of high electroluminescence intensity devices and will be conducive to better understanding on the relationship between electroluminescence principle and filler intrinsic attributes.
文摘ZnS ∶Cu nanoparticles were prepared by using microemulsion method at room temperature. The size of the particles is 2-8 nm by transmission electron microscopy (TEM) and dynamic light scattering (DLS) technique. X-ray diffraction analysis shows that the particles are cubic crystal structure, the same structure as the bulk ZnS materials. Ultraviolet absorption demonstrates an increased bandgap due to quantum confinement effect. Photoluminescence spectrum shows there is a single green emission band at 482 nm.
