共查询到20条相似文献,搜索用时 31 毫秒
1.
Jong Seong Bae Kyoo Sung Shim Soung-soo Yi Young Soo Kim 《Applied Surface Science》2006,252(13):4564-4568
The influence of lithium doping on the crystallization, the surface morphology, and the luminescent properties of pulsed laser deposited Y2−xGdxO3:Eu3+ thin film phosphors was investigated. The crystallinity, the surface morphology, and the photoluminescence (PL) of films depended highly on the Li-doping and the Gd content. The relationship between the crystalline and morphological structures and the luminescent properties was studied, and Li+ doping was found to effectively enhance not only the crystallinity but also the luminescent brightness of Y2−xGdxO3:Eu3+ thin films. In particular, the incorporation of Li and Gd into the Y2O3 lattice could induce remarkable increase in the PL. The highest emission intensity was observed Li-doped Y1.35Gd0.6O3:Eu3+ thin films whose brightness was increased by a factor of 4.6 in comparison with that of Li-doped Y2O3:Eu3+ thin films. 相似文献
2.
The effect of K+ ions on GdTaO4:Eu3+ thin-film phosphors was investigated in order to improve their luminescent properties. The GdTaO4:Eu0.1, Kx thin films were synthesized by sol-gel process, and characterized through measuring their microstructure and luminescence. The results indicated that photoluminescence (PL) intensity of GdTaO4:Eu3+ film was improved remarkably by K doping. There were two maxima in the curve of PL intensity against K+ dopant concentration, where one was improved up to 2.1 times at x = 0.001 and the other was enhanced up to 2.7 times at x = 0.05. The first maximum was regarded as the alteration of the local environment surrounding the Eu3+ activator by incorporation of K+ ions, and the second maximum was due to the flux effect. Additionally, the luminescence increased with the increase of firing temperature from 800 °C to 1200 °C. 相似文献
3.
K.S. Shim H.K. Yang B.K. Moon J.H. Jeong S.S. Yi K.H. Kim 《Applied Physics A: Materials Science & Processing》2007,88(4):623-626
Gd-substituted Y1-xGdxVO4:Eu3+ luminescent thin films have been grown on Al2O3(0001) substrates using pulsed-laser deposition. The films grown under different deposition conditions have been characterized
using microstructural and luminescent measurements. The crystallinity, surface morphology, and photoluminescence (PL) of the
films are highly dependent on the amount of Gd. The photoluminescence (PL) brightness data obtained from Y1-xGdxVO4:Eu3+ films grown under optimized conditions have indicated that the PL brightness is more dependent on the surface roughness than
the crystallinity of the films. In particular, the incorporation of Gd into the YVO4 lattice could induce a remarkable increase of PL. The highest emission intensity was observed with Y0.57Gd0.40Eu0.03VO4 thin film whose brightness was increased by a factor of 2.5 and 1.9 in comparison with that of YVO4:Eu3+ and GdVO4:Eu3+ films, respectively. This phosphor have application to flat panel displays.
PACS 78.20.-e; 78.55.-m; 78.66.-w 相似文献
4.
Hyun Kyoung Yang G. Seeta Rama Raju Byung Chun Choi Jung Hwan Kim 《Applied Surface Science》2009,255(9):5062-5066
CaTiO3:Pr3+ films were deposited on different substrates such as Al2O3 (0 0 0 1), Si (1 0 0), MgO (1 0 0), and fused silica using pulsed laser deposition method. The crystallinity and surface morphology of these films were investigated by XRD and SEM measurements. The films grown on the different substrates have different crystallinity and morphology. The FWHM of (2 0 0) peak are 0.18, 0.25, 0.28, and 0.30 for Al2O3 (0 0 0 1), Si (1 0 0), MgO (1 0 0), and fused silica, respectively. The grain sizes of phosphors grown on different substrates were estimated by using Scherrer's formula and the maximum crystallite size observed for the thin film grown on Al2O3 (0 0 0 1). The room temperature PL spectra exhibit only the red emission peak at 613 nm radiated from the transition of (1D2 → 3H4) and the maximum PL intensity for the films grown on the Al2O3 (0 0 0 1) is 1.1, 1.4, and 3.7 times higher than that of the CaTiO3:Pr3+ films grown on MgO (1 0 0), Si (1 0 0), and fused Sillica substrates, respectively. The crystallinity, surface morphology and luminescence spectra of thin-film phosphors were highly dependent on substrates. 相似文献
5.
S.S. Yi J.S. Bae K.S. Shim B.K. Moon H.J. Seo J.H. Jeong J.H. Kim 《Applied Physics A: Materials Science & Processing》2005,80(4):727-730
Gd2O3:Eu3+ and Li-doped Gd2O3:Eu3+ luminescent thin films have been grown on Si(100) substrates using pulsed laser deposition. The films grown at different deposition conditions show different crystalline and morphology structures and luminescent characteristics. Although both cubic and monoclinic crystalline structures were observed in both Gd2O3:Eu3+ and Li-doped Gd2O3:Eu3+ films, the cubic structure becomes more dominant for Li-doped Gd2O3:Eu3+ films. The photoluminescence brightness data obtained from Li-doped Gd2O3:Eu3+ films indicate that Si(100) is a promising substrate for growth of high-quality Li-doped Gd2O3:Eu3+ thin-film red phosphor. In particular, the incorporation of Li+ ions into the Gd2O3 lattice induced a change of crystallinity and enhanced surface roughness. Two major factors to determine photoluminescence brightness for Li-doped Gd2O3:Eu3+ films were crystalline phase and surface roughness. The highest emission intensity was observed with Gd1.84Li0.08Eu0.08O3, whose brightness was a factor of 2.1 larger than that of Gd2O3:Eu3+ films. This phosphor is promising for applications in flat-panel displays. PACS 78.20.-e; 78.55.-m; 78.66.-w 相似文献
6.
Transparent GdTaO4:Eu3+ thick films were prepared from the inorganic salt and 2-methoxyethanol solution containing polyvinylpyrrolidone (PVP) via sol-gel technique. The critical thickness of the film, i.e. the maximum thickness achievable without crack formation via non-repetitive deposition, was 0.8 μm. The effect of PVP on the morphology, crystallization behavior and optical property of the GdTaO4:Eu3+ thick film was investigated. The results indicated that PVP could play an important role in the formation of transparent GdTaO4:Eu3+ thick films, suppressing the stress evolution, adjusting the sol viscosity, ameliorating the crystallinity, and strengthening the covalency of Eu-O bonds. The GdTaO4:Eu3+ thick films prepared with PVP exhibited a superior photoluminescence and X-ray exited luminescence, which implies that it will have promising applications in high-spatial-resolution X-ray imaging and flat panel display devices. 相似文献
7.
Hyun Kyoung Yang Byung Kee Moon Jung Hyun Jeong Soung Soo Yi Kwang Ho Kim 《Journal of luminescence》2009,129(5):492-5107
YVO4:Sm3+ films were deposited on Al2O3 (0 0 0 1) substrates at various oxygen pressures changing from 13.3 to 46.6 Pa by using the pulsed laser deposition method. The crystallinity and surface morphology of these films were investigated by means of X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The XRD pattern confirmed that YVO4:Sm3+ film has zircon structure and the AFM study revealed that the films consist of homogeneous grains ranging from 100 to 400 nm. The room temperature photoluminescence (PL) spectra showed that the emitted radiation was dominated by a reddish-orange emission peak at 602 nm radiating from the transition of (4G5/2→6H7/2). The crystallinity, surface morphology, and photoluminescence spectra of thin-film phosphors were highly dependent on the deposition conditions, in particular, the substrate temperature. The surface roughness and photoluminescence intensity of these films showed similar behavior as a function of oxygen pressure. 相似文献
8.
Transparent Li-doped Gd2O3:Eu3+ thin-film phosphors were prepared by a modified sol-gel method. The effect of the Li+ ions on luminescent properties of the thin film was investigated. The results indicated that incorporation of Li+ ions into Gd2O3 lattice could result in a remarkable increase on photoluminescence or X-ray excited luminescence, and the strongest emission was observed from Gd1.84Li0.08Eu0.08O3−δ film, in which the intensity was increased by a factor of 1.9 or 2.3 in comparison with that of Gd1.92Eu0.08O3 film. And it could be achieved the highest intensity for sintering the Gd1.84Li0.08Eu0.08O3−δ film at 700 °C. Such a temperature is much lower than the typical solid-state reaction temperature for its powder phosphors. This kind of transparent thin-film phosphors may promise for application to micro X-ray imaging system. 相似文献
9.
Lingli Wang 《Journal of luminescence》2007,126(1):160-164
The luminescent properties of CaYBO4:Ln(Ln=Eu3+, Tb3+) were investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) region. The CT band of Eu3+ at about 245 nm blue-shifted to 230 nm in VUV excitation spectrum; the band with the maximum at 183 nm was considered as the host lattice absorption. For the sample of CaYBO4:0.08Tb3+, the bands at about 235 and 263 nm were assigned to the f-d transitions of Tb3+ and the CT band of Tb3+ was calculated according to Jφrgensen's theory. Under UV and VUV excitation, the main emission of Eu3+ corresponding to the 5D0-7F2 transition located at about 610 nm and two intense emission of Tb3+ from the 5D4-7F5 transition had been observed at about 542 and 552 nm, respectively. With the incorporation of Gd3+ into the host lattice of CaYBO4, the luminescence of Tb3+ was enhanced while that of Eu3+ was decreased because of their different excitation mechanism. 相似文献
10.
In this study, SrAl2O4:Eu2+,Dy3+ thin film phosphors were deposited on Si (1 0 0) substrates using the pulsed laser deposition (PLD) technique. The films were deposited at different substrate temperatures in the range of 40-700 °C. The structure, morphology and topography of the films were determined by using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Photoluminescence (PL) data was collected in air at room temperature using a 325 nm He-Cd laser as an excitation source. The PL spectra of all the films were characterized by green phosphorescent photoluminescence at ∼530 nm. This emission was attributed to 4f65d1→4f7 transition of Eu2+. The highest PL intensity was observed from the films deposited at a substrate temperature of 400 °C. The effects of varying substrate temperature on the PL intensity were discussed. 相似文献
11.
Isao Tanaka Youji InoueKatsu Tanaka Yoshitaka IzumiShinji Okamoto Mitsuhiro KawanishiNoboru Miura Hironaga MatsumotoRyotaro Nakano 《Journal of luminescence》2002,96(1):69-74
We characterized the crystallization and luminescence of blue-emitting BaAl2S4 : Eu electroluminescent thin films, prepared using switching electron-beam evaporation with two targets. From the photoluminescence intensity and decay profile of the activated Eu2+ ions in the BaAl2S4 : Eu, we found that the optimum annealing conditions for preparing highly luminescent thin films are a temperature of around 900°C and an annealing time of 2 min. We analyzed the crystalline properties using cross-sectional transmission electron microscope images. Evaluation of the cathodoluminescence spectra in the cross-sections showed that the BaAl2S4 : Eu emitting layer was luminously inhomogeneous on the depth of the layer and that the main luminescent area was near the surface of the emitting layer. We discuss here the relationship between the crystalline and luminescent properties. 相似文献
12.
E. Coetsee 《Physica B: Condensed Matter》2009,404(22):4431-4435
Three different gases (nitrogen (N2), oxygen (O2) and argon (Ar)) were used as background gases during the growth of pulsed laser deposition (PLD) Y2SiO5:Ce thin films. A Krypton fluoride laser (KrF), 248 nm was used for the PLD of the films on silicon (Si) (1 0 0) substrates. The effect of the background gases on the surface morphology, crystal growth and luminescent properties were investigated. All the experimental parameters, the gas pressure (455 mT), the substrate temperature (600 °C), the pulse frequency (8 Hz), the number of pulses (4000) and the laser fluence (1.6±0.2) J/cm2 were kept constant. The only parameter that was changed during the deposition was the ambient gas species. The surface morphology and average particle sizes were monitored with scanning electron microscopy (SEM) and atomic force microscopy (AFM). X-ray diffraction (XRD) and Auger electron spectroscopy (AES) were used to determine the crystal structure and composition, respectively. Cathodo- (CL) and photoluminescence (PL) were used to measure the luminescent intensities for the different phosphor thin films. The nature of the particles, ablated on the substrate, is related to the collisions between the ejected particles and the ambient gas particles. The CL and PL intensities also depend on the particle sizes. A 144 h (coulomb dose of 1.4×104 C cm−2) electron degradation study on the thin films ablated in the Ar gas environment resulted in a decrease in the main CL intensity peak at 440 nm and to the development of a new very broad luminescent peak spectra ranging from 400 to 850 nm due to the growth of a SiO2 layer on the surface. 相似文献
13.
J.S. Bae S.S. Yi J.H. Kim K.S. Shim B.K. Moon J.H. Jeong Y.S. Kim 《Applied Physics A: Materials Science & Processing》2006,82(2):369-372
Gd2O3:Eu3+ luminescent thin films have been grown on Al2O3(0001) substrates using pulsed-laser deposition. The films grown at different deposition conditions showed different crystalline
phases, surface morphologies and luminescent characteristics. Both cubic and monoclinic crystalline phases were observed for
the Gd2O3:Eu3+ films, and the crystalline structure and the surface morphology of the films were highly dependent on the oxygen pressure
and substrate temperature. The cubic system showed a higher luminescence than the monoclinic system. The luminescence characteristics
were strongly influenced by not only the crystalline structure but also the surface morphology of the films. The photoluminescencebrightness
data obtained from Gd2O3:Eu3+ films indicate that Al2O3(0001) is a promising substrate for growth of high-quality Gd2O3:Eu3+ thin-film red phosphor. In particular, the Gd2O3:Eu3+ films showed a much better photoluminescence behavior than a Y2O3:Eu3+ films with the same thickness.
PACS 78.20.-e; 78.55.-m; 78.66.-w 相似文献
14.
Zinc silicate phosphors co-doped with Eu3+ ions and also with both Eu3+ and Tb3+ ions were prepared by high temperature solid state reaction in air or reducing atmosphere. The luminescence characteristics of the prepared phosphors were investigated. While in the samples prepared in air, Eu3+ emission was found to be dominant over Tb3+ emission, in the samples prepared in reducing atmosphere, intense Eu2+ emission at 448 nm was found to be predominant over narrow Tb3+ emission. Luminescence studies showed that Eu3+ ions occupy asymmetric sites in Zn2SiO4 lattice. The intense f-f absorption peak of Eu3+ at 395 nm observed in these phosphors suggests their potential as red emitting phosphors for near ultra-violet light emitting diodes. 相似文献
15.
Potential PDP phosphors with strong absorption around 172 nm: Rare earth doped NaLaP2O7 and NaGdP2O7
Jun Lin Yuan Jiao Wang Ding Bang Xiong Jing Tai Zhao Yi Bing Fu Chao Shu Shi 《Journal of luminescence》2007,126(2):717-722
NaLaP2O7 and NaGdP2O7 powder samples are prepared by solid-state reactions at 750 and 600 °C, respectively, and the VUV-excited luminescence properties of Ln3+ (Ln=Ce, Pr, Tb, Tm, Eu) in both diphosphates are studied. Ln3+ ions in both hosts show analogous luminescence. For Ce3+-doped samples, the five Ce3+ 5d levels can be clearly identified. As for Pr3+ and Tb3+-doped samples, strong 4f-5d absorption band around 172 nm is observed, which matches well with Xe-He excimer in plasma display panel (PDP) devices. As a result, Pr3+ can be utilized as sensitizer to absorb 172 nm VUV photon and transfer energy to appropriate activators, and Tb3+-doped NaREP2O7(RE=La, Gd) are potential 172 nm excited green PDP phosphors. For Tm3+ and Eu3+-doped samples, the Tm3+-O2− charge transfer band (CTB) is observed to be at 177 nm, but the CTB of Eu3+ is observed at abnormally low energy position, which might originate from multi-position of Eu3+ ions. The similarity in luminescence properties of Ln3+ in both hosts indicates certain structural resemblance of coordination environment of Ln3+ in the two sodium rare earth diphosphates. 相似文献
16.
Dong Wang Piaoping Yang Ziyong Cheng Wenxin Wang Pingan Ma Xuefeng Zhai Jun Lin 《Journal of nanoparticle research》2012,14(1):707-10
Ordered arrays of luminescent GdVO4:Ln (Ln = Eu3+, Dy3+, Sm3+) films with dot patterns have been successfully fabricated via microcontact printing method. The soft-lithography process
utilizes a PDMS elastomeric mold as the stamp combined with a Pechini-type sol–gel process to produce luminescent patterns
on quartz plates, in which a GdVO4:Ln (Ln = Eu3+, Dy3+, Sm3+) precursor solution was employed as ink. The ordered luminescent GdVO4:Ln patterns were revealed by optical microscopy and their microstructure, consisting of nanometer-scale particles, as demonstrated
by scanning electronic microscopy observations. In addition, photoluminescence and cathodoluminescence were carried out to
characterize the patterned GdVO4:Ln (Ln = Eu3+, Dy3+, Sm3+) samples. Upon UV-light or electron-beam irradiation, the rare earth ions Eu3+, Dy3+, and Sm3+ in the crystalline GdVO4 host show their characteristic transitions dominated by 5D0–7F2, 4F9/2–6H13/2 ,and 4G5/2–6H7/2, respectively. These results make the combining soft lithography with a Pechini-type sol–gel route have potential applications
as rare-earth luminescent pixels for next-generation field-emission display devices. 相似文献
17.
M. Calixto-Rodriguez H. Martínez O. Flores A. Sanchez-Juarez P. Reyes 《Applied Surface Science》2010,256(8):2428-7591
As-deposited antimony sulfide thin films prepared by chemical bath deposition were treated with nitrogen AC plasma and thermal annealing in nitrogen atmosphere. The as-deposited, plasma treated, and thermally annealed antimony sulfide thin films have been characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, UV-vis spectroscopy, and electrical measurements. The results have shown that post-deposition treatments modify the crystalline structure, the morphology, and the optoelectronic properties of Sb2S3 thin films. X-ray diffraction studies showed that the crystallinity of the films was improved in both cases. Atomic force microscopy studies showed that the change in the film morphology depends on the post-deposition treatment used. Optical emission spectroscopy (OES) analysis revealed the plasma etching on the surface of the film, this fact was corroborated by the energy dispersive X-ray spectroscopy analysis. The optical band gap of the films (Eg) decreased after post-deposition treatments (from 2.36 to 1.75 eV) due to the improvement in the grain sizes. The electrical resistivity of the Sb2S3 thin films decreased from 108 to 106 Ω-cm after plasma treatments. 相似文献
18.
Cathodoluminescent (CL) spectra of Li-doped Gd2−xYxO3:Eu3+ solid-solution (0.0?x?0.8) were investigated at low voltages (300 V-1 kV). The CL intensity is maximum for the composition of x=0.2 and gradually reduces with increasing the amount of substituted Y content. In particular, small (∼100 nm) particles of Li-doped Gd1.8Y0.2O3:Eu3+ are obtained by firing the citrate precursors at only 650°C for 18 h. Relative red-emission intensity at 300 V of this phosphor is close to 180% in comparison with that of commercial red phosphor Y2O3:Eu3+. An increase of firing temperature to 900°C results in 400-600 nm sized spherical particles. At low voltages (300-800 V), the CL emission of 100 nm sized particles is much stronger than that of 400-600 nm sized ones. In contrast, the larger particles exhibit the higher CL emission intensity at high voltages (1-10 kV). Taking into consideration small spherical morphology and effective CL emission, Li-doped Gd1.8Y0.2O3:Eu3+ appears to be an efficient phosphor material for low voltage field emission display. 相似文献
19.
Luminescence properties of Eu3+ doped TeO2-PbO-GeO2 glasses containing gold nanoparticles (NPs) were investigated. The emission spectra of the samples exhibited enhancement of Eu3+ luminescence due to the presence of gold NPs. The emission at 614 nm, due to the Eu3+ hypersensitive transition 5D0-7F2, is much influenced by the gold NPs and increases by ≈100% for samples heat-treated at 350 °C during 41 h. 相似文献
20.
Zuoling Fu 《Journal of luminescence》2009,129(12):1669-359
In this paper, the Ca2SnO4:Eu3+ phosphor was prepared by low-temperature sol-gel method. The influence of calcined temperature and time on structure of Ca2SnO4:Eu3+ was investigated by using X-ray powder diffraction (XRD). The experimental results show that the dried gel was crystallized to the pure orthorhombic phase after calcination at 900 °C in air for 6 h. These phosphors have displayed bright red color under a UV source. The richness of the red color has been verified by determining their color coordination from the CIE standard charts, and this red emission has been assigned to 5D0→7F2 electric dipole transition at 616 and 620 nm. The excellent luminescence properties make it possible as a good candidate for plasma display panel (PDP) application. 相似文献