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Synthesis,structure,and luminescence properties of melilite Dy^(3+):Lu_(x)CaLa_(0.98-x)Ga_(3)O_(7) phosphors for use in yellow light-emitting devices

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Journal of Rare Earths 2024年第8期42卷 1489-1495,I0003页

作者： Yunyun Liu Chuanxin Huang Meng Wang Xihu Wang Yan Wang Ju Gao School of Opto-Electronic Engineering Zaozhuang UniversityZaozhuang277160China Key Laboratory of Functional Materials and Devices for Informatics of Anhui Educational Institutions Department of PhysicsFuyang Normal UniversityFuyang236037China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou350002.China

Dy^(3+) and Lu^(3+) co-doped CaLaGa_(3)O_(7) phosphors were prepared via high-temperature solid-phase *** electronic structures of LuxCaLa_(0.98-x)Ga_(3)O_(7) were investigated by the first-principles *** influence of Lu^(3+) on yellow light emission was studied using X-ray diffraction(XRD)and photoluminescence(PL) *** XRD results indicate that compared to Dy^(3+):CaLaGa_(3)O_(7),the cell parameters of Dy^(3+):LuCaLaGa_(3)O_(7) tend to decrease,which is due to the smaller radius of Lu^(3+).When pumped by blue GaN laser diode(LD),the emission peaks of phosphors with different Lu^(3+)doping concentrations in the visible region are similar,with the strongest peak at 574 nm in the yellow light region,which is sensitive to human *** optimal doping concentration of Lu^(3+) is confirmed to be1 at%,when all emission spectra and measured fluorescence lifetimes are taken into ***,the optimal phosphor composition Dy^(3+):Lu_(x)CaLa_(0.98-x)Ga_(3)O_(7)(x=0.01) has an internal quantum efficiency(IQE) of 46.94% and an external quantum efficiency(EQE) of 15.19%.Most notably,the prepared phosphor demonstrates excellent thermal stability and a high activation energy(0.203 eV).In addition,the International Illumination Commission color coordinates of the Dy^(3+):LuxCaLa_(0.98-x)Ga_(3)O_(7) phosphors are in the yellow light *** above analysis indicates that the Dy^(3+):LuxCaLa_(0.98-x)Ga_(3)O_(7)(x=0.001)phosphor has promising application prospects in yellow light-emitting devices.

关键词： Dy^(3+):Lu_(x)CaLa_(0.98-x)Ga_(3)O_(7)phosphors yellow emission Structure characteristics Luminescent properties Rare earths

How ligand coordination and superatomic-states accommodate the structure and property of a metal cluster:Cu_(4)(dppy)_(4)Cl_(2)***_(21)(dppy)_(10)with altered photoluminescence

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Chinese Chemical Letters 2024年第1期35卷 528-532页

作者： Haiming Wu Gaya NAndrew Rajini Anumula Zhixun Luo Beijing National Laboratory for Molecular Sciences(BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemistry University of Chinese Academy of SciencesBeijing 100049China

We have synthesized two copper nanoclusters(NCs)with a protection of the same ligand diphenylphosphino-2-pyridine(C_(17)H_(14)NP,dppy for short),formulated as Cu_(4)(dppy)_(4)Cl_(2)and Cu21(dppy)10,*** former one bears a distorted tetrahedron Cu4 core with its six edges fully protected by chlorine and dppy ligands,while the latter presents a symmetric Cu_(21)core on which ten dppy molecules function as monolayer protection via well-organized monodentate or bidentate ***,the Cu_(4)(dppy)_(4)Cl_(2)cluster exhibits a strong yellow emission at∼577 nm,while Cu_(21)(dppy)_(10)displays dual emissions in purple(∼368 nm)and green(∼516 nm)regions *** combination with TD-DFT calculations,we demonstrate the origin of altered emissions and unique stability of the two copper nanoclusters pertaining to the ligand coordination and metallic superatomic states.

关键词： Copper nanocluster yellow emission Dual emission Superatomic states Ligand dppy

Photoluminescence and thermal stability of yellow-emitting Pr^(3+) doped CaAl_(2)O_(4) phosphors

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Journal of Advanced Dielectrics 2013年第3期3卷 31-35页

作者： Hua Zou Dengfeng Peng Zhenming Chu Xusheng Wang Yanxia Li Jun-Wei Hou Xi Yao Functional Materials Research Laboratory Tongji University Siping Road 1239Shanghai 200092P.R.China School of Material Science and Engineering Tongji University Shanghai 201804P.R.China

Pr^(3+)-doped CaAl_(2)O_(4) phosphors with broad yellow emission were synthesized by conventional solid-state reaction in air and their structural and luminescent properties were investigated.A pure monoclinic structure can be obtained when the sintering temperature is 1400℃ or *** photoluminescence(PL)measurement,the excitation was observed at 450–500 nm,which covered the emission of the blue light-emitting diode(LED)*** of the phosphors showed a green band and a red *** these phosphors showed great potential in application of warm white LEDs without ***,the optimal emission intensity was obtained when Pr doping level was at 0.2 mol%.Furthermore,the Pr-doped CaAl_(2)O_(4) phosphors have the higher quenching *** an increase in temperature,the emission bands of Pr-doped CaAl_(2)O_(4) showed an abnormal blue-shift.

关键词： Phosphors CaAl_(2)O_(4) yellow emission blue excitation thermal stability

Structural and Optical Performance of GaN Thick Film Grown by HVPE

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Journal of Semiconductors 2007年第1期28卷 19-23页

作者：魏同波马平段瑞飞王军喜李晋闽刘喆林郭强曾一平中国科学院半导体研究所北京100083

Thick GaN films were grown on GaN/sapphire template in a vertical HVPE reactor. Various material characterization techniques,including AFM, SEM, XRD, RBS/Channeling, CL, PL, and XPS, were used to characterize these GaN epitaxial films. It was found that stepped/terraced structures appeared on the film surface,which were indicative of a nearly step-flow mode of growth for the HVPE GaN despite the high growth rate. A few hexagonal pits appeared on the surface, which have strong light emission. After being etched in molten KOH, the wavy steps disappeared and hexagonal pits with {1010} facets appeared on the surface. An EPD of only 8 ×10^6cm^-2 shows that the GaN film has few dislocations. Both XRD and RBS channeling indicate the high quality of the GaN thick films. Sharp band-edge emission with a full width at half maximum（FWHM）of 67meV was observed, while the yellow and infrared emissions were also found. These emissions are likely caused by native defects and C and O impurities.

关键词： GaN HVPE CL RBS/channeling yellow emission infrared emission