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1.
Recently, long persistent phosphors (LPPs) have attracted significant attention as promising candidates for biomedical applications. However, the serious decrease in luminescence intensity in tissue still remains a major challenge. Therefore, exploring more competitive LPPs and achieving reproducible tissue imaging is crucial. In this study, a new series of near-infrared (NIR) phosphors La3Ga5Sn1-xO14:xCr3+ (x = 0.005–0.05) were synthesized using a high-temperature solid-state method. The as-synthesized samples were characterized using X-ray diffraction, diffuse/photoluminescence spectroscopy, fluorescence decay curves, and thermoluminescence spectroscopy. Upon excitation with ultraviolet light, strong emission bands were observed in the range 600–1200 nm with an optimal doping concentration of x = 0.02 mol. Moreover, La3Ga5SnO14:Cr3+ exhibits persistent luminescence due to the presence of suitable energy traps, which prompted the phosphor to emit NIR light even after the removal of the excitation source. 相似文献
2.
Kapil Dev Anupam Selot Govind B. Nair Vijay L. Barai Nitu Singh Fozia Z. Haque M. Aynyas S. J. Dhoble 《Luminescence》2019,34(8):804-811
Dy3+‐doped CaAl12O19 phosphors were synthesized utilizing a combustion method. Crystal structure and morphological examinations were performed respectively using X‐ray diffraction (XRD) and scanning electron microscopy (SEM) techniques to identify the phase and morphology of the synthesized samples. Fourier transform infrared spectroscopy (FTIR) estimations were carried out using the KBr method. Photoluminescence properties (excitation and emission) were recorded at room temperature. CaAl12O19:Dy3+ phosphor showed two emission peaks respectively under a 350‐nm excitation wavelength, centered at 477 nm and 573 nm. Dipole–dipole interaction via nonradiative energy shifting has been considered as the major cause of concentration quenching when Dy3+ concentration was more than 3 mol%. The CIE chromaticity coordinates positioned at (0.3185, 0.3580) for the CaAl12O19:0.03Dy3+ phosphor had a correlated color temperature (CCT) of 6057 K, which is situated in the cool white area. Existing results point out that the CaAl12O19:0.03Dy3+ phosphor could be a favorable candidate for use in white light‐emitting diodes (WLEDs). 相似文献
3.
Hui Wang Lingling Wang Meihua Wu Minghao Fang Zhaohui Huang Xin Min 《Luminescence》2023,38(2):208-215
This paper reports a sequence of a Ca3YAl3B4O15:xEu3+ red phosphor prepared using a high-temperature solid-state reaction. At the excitation of 396 nm, the samples emitted intense red emission centred at ~623 nm, which could be attributed to the 5D0→7F2 transition of the Eu3+ ion. The results showed that the optimum Eu3+ doping concentration of Ca3YAl3B4O15:Eu3+ phosphor was x = 80 mol%, and the concentration quenching mechanism of Ca3YAl3B4O15:Eu3+ red phosphor belonged to the exchange coupling between Eu3+ ions. The Commission Internationale de l'éclairage (CIE) coordinates and colour purity of Ca3Y0.2Al3B4O15:0.8Eu3+ were calculated as (0.6375, 0.3476) and 95.5%, respectively. Moreover, the red emission of the obtained phosphor Ca3YAl3B4O15:0.8Eu3+ exhibited a low thermal quenching behaviour with an intensity retention rate of 92.85% at 150°C. The above results manifest that the Eu3+-activated Ca3YAl3B4O15 phosphor is predicted to be a promising red luminescent component for white light-emitting diodes. 相似文献
4.
A dysprosium (Dy3+)-activated potassium calcium silicate (K4CaSi3O9) phosphor was prepared using a solid-state synthesis route. The phosphor had a cubic structure with the space group Pa as confirmed using X-ray diffraction (XRD) measurements. Details of surface morphology and elemental composition of the as-synthesized undoped KCS phosphor was obtained using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. The chemical structure as well as the vibrational modes present in the as-prepared KCS phosphor was analyzed using Fourier transform infrared (FT-IR) spectroscopy. Diffuse reflectance spectra (DRS) were used to determine the optical bandgap of the phosphors and were found to be in the optical range 3.52–3.71 eV. Photoluminescence (PL) spectra showed intense yellow emission corresponding to the 4F9/2→6H13/2 transition under 350 nm excitation. Commission International de l′Eclairage colour chromaticity coordinates were evaluated using the PL spectral data lie within the white region. Dexter theory and the Inokuti–Hirayama (I–H) model were applied to study the nature of the energy transfer mechanism in the as-prepared phosphors. The relatively high activation energy of the phosphors was evaluated using temperature-dependent PL (TDPL) data and confirmed the high thermal stability of the titled phosphor. The abovementioned results indicated that the as-prepared KCS:Dy3+ phosphor was a promising candidate for n-UV-based white light-emitting diodes. 相似文献
5.
A novel red emitting phosphor LiBaB9O15:Sm2+/Sm3+, li+ with broad excitation band for white LEDs
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A novel tunable red emitting phosphor LiBaB9O15:Sm2+/Sm3+, Li+ with broad excitation band was synthesized by a high temperature solid‐state method. Luminescence properties were investigated in detail by luminescence, X‐ray photoelectron spectroscopy (XPS) spectra and CIE chromaticity coordinates. XPS data confirmed that there were Sm3+ in LiBaB9O15:Sm3+ and Sm2+/Sm3+ in LiBaB9O15:Sm2+/Sm3+, respectively. Spectral property of LiBaB9O15:Sm3+, LiBaB9O15:Sm3+/Sm2+ and LiBaB9O15:Sm2+, Li+ presented that the excitation band of Sm3+ widened and the excitation band of Sm2+ ranged from 350 to 450 nm. And the red light color is tunable with changing Li+ concentration. The results indicated that LiBaB9O15:Sm2+/Sm3+, Li+ may be promising red phosphor for white light emitting diodes. 相似文献
6.
We developed a facile strategy for the fabrication of red fluorescent carbon nanodots (R-CDs) and demonstrated their applications for Al3+ sensing. Red-emission carbon dots (CDs) were synthesized using a simple hydrothermal treatment with citric acid and urea as precursors, manifesting intriguing red-emission behaviour at 610 nm. With increasing Al3+ concentration, the fluorescence band at 610 nm decreased gradually. Monitoring the intrinsic fluorescence variation (I610nm), as-prepared CDs were developed as an effective platform for fluorescent Al3+ sensing, with a linear range of 0.5–60.0 μM and a detection limit of 3.0 nM. More importantly, R-CDs have been applied successfully to the analysis of Al3+ in actual samples with satisfactory recoveries in the range 97.12–102.05%, which indicated that obtained CDs could be implemented as an effective tool for the identification and detection of Al3+ in actual samples. 相似文献
7.
Yongfu Teng 《Luminescence》2019,34(4):432-436
In the Ba9Lu2Si6O24 (BLS) host, Ce3+ shows cyan emissions peaking at 490 nm under 400 nm excitations. BLS:Tb3+ only can be effectively excited by 254 nm light and gives rise to green emissions at 553 nm. However, both the cyan and green emissions can be obtained in BLS:Ce3+,Tb3+ under 400 nm excitations due to effective energy transfers from Ce3+ to Tb3+. BLS:Mn2+ shows red emissions peaking at 610 nm under 414 nm excitations. By co‐doping Ce3+, Tb3+ and Mn2+, tunable full‐color emissions were obtained. The BLS:0.3Ce3+,0.6Tb3+,0.15Mn2+ single phosphor exhibits a white light with a high color rendering index of 85 and a correlated color temperature of 5480 K under 400 nm excitation. 相似文献
8.
Near-infrared light sources have potential applications in many fields. Cr3+ is a good luminescence centre to prepare near-infrared phosphors. Improving the performance of existing near-infrared luminescent materials has indeed attracted great interest from researchers. The luminescence properties of Zn2TiO4:Cr3+ were improved by crystal field engineering strategies. Zn2+–Ti4+ was partially replaced using a Li+–Nb5+ ion pair based on the Zn2TiO4:Cr3+ phosphors. Luminescence Cr3+-activated luminescent materials are sensitive to changes in the local crystal structure and crystal field environment. Doping of Li+–Nb5+ increased the luminescence intensity up to 2.7 times that of the undoped sample. Also, the thermal stability of the phosphor was greatly increased by the replacement of Li+–Nb5+. 相似文献
9.
Eu(2+), Dy(3+) and Tb(3+) co-doped strontium aluminate phosphor with high brightness and long afterglow was synthesized by a combustion method, using urea as a reducer. The properties of SrAl(2)O(4):Eu(2+),Dy(3+),Tb(3+) phosphor with a series of initiating combustion temperatures, urea concentrations and boric acid molar fractions were investigated. The sample at initiating combustion temperature of 600 degrees C exhibited an intense emission peak at 513 nm, in which the phosphor existed as a single-phase monoclinic structure. The experimental results showed that the optimum ratio of urea is 2.0 times higher than theoretical quantities and that the suitable molar fraction of H(3)BO(3) is 0.08. The average particle size of the phosphor was 50-80 nm and its luminescence properties were studied systematically. Compared with SrAl(2)O(4):Eu(2+),Dy(3+) phosphor, the initial luminescence brightness improved from 2.50 candela (cd)/m(2) to 3.55 cd/m(2) and the long afterglow time was prolonged from 1290 s to 2743 s. 相似文献
10.
Synthesis and luminescence properties of CaSnO3:Bi3+ blue phosphor and the emission improvement by Li+ ion
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Renping Cao Jinlong Zhang Wudi Wang Qianglin Hu Wensheng Li Wen Ruan Hui Ao 《Luminescence》2017,32(6):908-912
CaSnO3:Bi3+ blue‐emitting phosphor was synthesized using a high‐temperature solid‐state reaction method in air. The crystal structures and luminescence properties were investigated. A broad emission band peaking at ~448 nm upon excitation at 262 and 308 nm was observed in the range 330–680 nm at room temperature due to 3P1 → 1S0 transition of the Bi3+ ion. The chromaticity coordinate was (0.1786, 0.1665). The optimal Bi3+ ion concentration was ~0.6 mol% in CaSnO3:Bi3+ phosphor. The emission spectrum of CaSnO3:Bi3+ phosphor showed a blue‐shift with increasing temperature from 50 to 300 K due to the influence of temperature on the electron transition of the Bi3+ ion. The emission intensity of CaSnO3:Bi3+ phosphor may be increased ~1.45 times by co‐doping Li+ ions as a charge compensator and fluxing agent. The luminescence mechanism is explained by a configurational coordinate diagram of Bi3+ ion in CaSnO3:Bi3+ phosphor. 相似文献
11.
脱色希瓦氏菌S12的铁还原性能研究 总被引:5,自引:0,他引:5
从印染废水中分离得到了一株具有染料脱色功能的希瓦氏菌脱色新种。该菌能在厌氧条件下利用Fe^3+作为末端电子受体获得能量,支持细胞生长。在pH8.0.温度30℃。柠檬酸铁800mg/L,乳酸钠2g/L,酵母抽提物0.5g/L的条件下,培养8h的过程中,菌体细胞量的增长完全与Fe^3+的还原发展趋向一致。同时考察了碳氮源、乳酸钠、酵母抽提物、pH值和温度等方面对该菌株的生长和铁还原特性的影响。结果表明,菌体生长以LB为最好,以葡萄糖和乳酸钠为碳源时对铁还原有利。在酵母抽提物浓度4g/L范围内,菌体生长量和铁还原率随着酵母抽提物浓度的提高而提高。当乳酸钠为6g/L时,S12菌体生长量和铁还原率达到最佳。柠檬酸铁浓度为800mg/L时菌体生长量和铁还原率最高。在起始pH6-8的范围内,菌株S12的生长随着pH升高而升高,这也是菌株S12进行铁还原的最佳pH范围。菌株S12在温度范围20℃-40℃内均可生长和进行铁还原,而以30℃时最佳。 相似文献
12.
A sensitive SERS quantitative analysis method for Ni2+ by the dimethylglyoxime reaction regulating a graphene oxide nanoribbon catalytic gold nanoreaction
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The nanogold reaction between HAuCl4 and trisodium citrate (TCA) proceeded very slowly at 60°C in a water bath. The as‐prepared graphene oxide nanoribbons (GONRs) exhibited strong catalysis during the reaction to form gold nanoparticles (Au NPs) and appeared as a strong surface‐enhanced Raman scattering (SERS) peak at 1616 cm?1 in the presence of the molecular probe Victoria blue 4R (VB4r). With increase in GONR concentration, the SERS peak increased due to increased formation of Au NPs. Upon addition of dimethylglyoxime (DMG) ligand, which was adsorbed onto the GONR surface to inhibit GONR catalysis, the SERS peak decreased. When Ni2+ was added, a coordination reaction between DMG and Ni2+ took place to form stable complexes of [Ni (DMG)2]2+ and the release of free GONR catalyst that resulted in the SERS peak increasing linearly. A SERS quantitative analysis method for Ni2+ was therefore established, with a linear range of 0.07–2.8 μM, and a detection limit of 0.036 μM Ni2+. 相似文献
13.
Crystal structure and luminescence properties of the blue‐green‐emitting Ba9(Lu,Y)2Si6O24:Ce3+ phosphor
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Huawei Xu Zhi Zhou Yongfu Liu Qunxing Liu Zhiyuan He Shen Wang Linyi Huang Hongbo Zhu 《Luminescence》2017,32(5):812-816
Samples of the Ba9(Lu2‐xYx)Si6O24:Ce3+ (x = 0–2) blue‐green phosphors were synthesized by solid‐state reactions. All the samples exhibited a rhombohedral crystal structure. As the Y3+ concentration increased, the diffraction peaks shifted to the small angle region and the lattice parameters increased due to the larger ionic radius of Y3+ (r = 0.900 Å) compared with that of Lu3+ (r = 0.861 Å). Under 400 nm excitation, samples exhibited strong blue‐green emissions around 490 nm. The emission bands had a slight blue shift that resulted from weak crystal‐field splitting with increasing Y3+ concentration. Luminescence intensity and quantum efficiency (QE) decreased with increasing Y3+ concentration. The internal QE decreased from 74 to 50% and the external QE decreased from 50 to 34% as x increased from 0 to 2. The thermal stability of the Lu series was better than that of the Y‐series. The excitation band peak around 400 nm matched well with the emission light from the efficient near‐ultraviolet (NUV) chip. These results indicate promising applications for these NUV‐based white light‐emitting diodes. 相似文献
14.
Brüggemann, W. and Moog, P. R. 1989. NADH-dependent Fe3+EDTA and oxygen reduction by plasma membrane vesicles from barley roots. Biochemical properties of pyridine-dinucleotide-dependent Fe3+-EDTA reductase were analysed in purified plasma membranes (PM) from barley (Hordeum vulgare L. cv. Marinka) roots. The enzymatic activity preferred NADH over NADPH as electron donor and it was 3-fold increased in the presence of detergent. The reductase showed a pH optimum of 6.8 and saturable kinetics for NADH with Km (NADH) of 125 μM and Vmax of 143 nmol Fe (mg protein)-1 min-1 in the presence of 500 μM Fe3+EDTA. For the dependence of the reaction rate on the iron compound, Km(Fe3+EDTA) of 120 μM and Vmax of 184 nmol (mg protein)-1 min-1 were obtained. The activity was insensitive to superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6) and antimycin A, but stimulated by an oxygen-free reaction medium. It could be solubilized by 0.25% (w/v) Triton X-100. The solubilized enzyme revealed one band in native polyacrylamide gel electrophoresis (PAGE) and in isoelectric focussing (IEF) at pl 7.4 by enzyme staining. Major polypeptides with molecular weights of 94, 106, 120 and 205 kDa corresponded to the enzyme-stained band from native PAGE. Analysis of oxygen consumption by the membranes revealed the existence of NADH:CK oxidoreductase activity, which was stimulated by salicylhydroxamic acid (SHAM), chinhydron, Fe3+EDTA and Fe3+EDTA but not by K3 [Fe(CN)6] or K4[Fe (CN)6). The stimulating effect of the iron chelates on oxygen consumption was due to Fe2+ and could be suppressed by bathophenanthroline disulfonate (BPDS), SOD and p-chloromercurophenylsulfonic acid (PCMS). The results are discussed with respect to the nature of the stimulation. 相似文献
15.
A series of Ce3+‐activated blue‐emitting phosphors BaY2Si3O10 (BYSO) was designed and synthesized by a conventional solid‐state method. Upon ultraviolet light (250–370 nm) excitation, the obtained phosphors showed an intense blue emission band centered at 400–427 nm depending on doping concentration, and corresponding to the 5d→4f transition of Ce3+. The effects of doping concentration on crystal structure, emitting color, photoluminescence and photoluminescence excitation spectra, as well as the concentration quenching mechanism were studied in detail. The optimal doping concentration of Ce3+ in this phosphor was demonstrated to be about 0.75% and the concentration quenching mechanism can be ascribed to electric dipole–dipole interactions with a critical distance of ~38 Å. These fine luminescence properties indicate that BYSO:Ce3+ may be a potential blue phosphor for full‐color ultra‐violet (UV) white light emitting diodes (WLEDs). 相似文献
16.
Enhanced photoluminescence of the Ca0.8Zn0.2TiO3:0.05% Pr3+ phosphor by optimized hydrothermal conditions
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Mao Xia Guanhua Wang Zhiqiang Gu Zhongxian Qiu Chunying Rong Jilin Zhang Wenli Zhou Liping Yu Shixun Lian 《Luminescence》2017,32(6):999-1008
The red‐emitting phosphor Ca0.8Zn0.2TiO3:Pr3+ was synthesized using an ethylene glycol (EG)‐assisted hydrothermal method. The effects of additional amounts of and order of adding EG, plus hydrothermal temperature, time, and pH on the composition, morphology and optical properties of the titanate phosphors were studied. The crystalline phases of the titanate phosphors were confirmed to be constituted of a series of co‐existing CaTiO3, Zn2TiO4 and Ca2Zn4Ti16O38 compounds in various proportions that were visualized using an X‐ray diffractometer (XRD). The optical properties of the phosphors were studied using photoluminescence spectra and UV–visible spectroscopy. The results show that the impurities Zn2TiO4:Pr3+ and Ca2Zn4Ti16O38:Pr3+ significantly contributed to the enhancement of an absorption band around 380 nm. The optimum Ca0.8Zn0.2TiO3:Pr3+ phosphor consisting of appropriate amounts of CaTiO3, Ca2Zn4Ti16O38 and Zn2TiO4 in three phases was achieved by controlling the hydrothermal conditions, and the obtained red phosphor exhibited the highest red emission (1D2 → 3H4 transition of Pr3+) with an ideal chromaticity coordinate located at (x = 0.667, y = 0.332) under 380 nm excitation. 相似文献
17.
Calcium aluminate phosphor co‐doped Eu2+, Dy3+, Nd3+ is prepared by the combustion method. We study systemically the influences of the quantity of mixed Dy3+ ion, the quantity of flux H3BO3, the differences in dispersing methods between magnetic stirring and ultrasonic dispersing and the combustion temperature on the long‐persistence phosphor. The analytical results indicate that Dy3+ ion improves the properties of the phosphors CaAl2O4:Eu2+, Nd3+. The appropriate quantity of flux H3BO3 to reduce the forming temperature of the sample was determined. The monoclinic single phase of CaAl2O4 formed at 500°C and remained steady. The calcium aluminate co‐doped Eu2+, Dy3+, Nd3+ was synthesized by dispersal of the raw material using the ultrasonic method, and it had better optical properties. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
18.
Xu Kuai Guangming Yang Yubo Chen Hainan Sun Jie Dai Yufei Song Ran Ran Wei Wang Wei Zhou Zongping Shao 《Liver Transplantation》2019,9(38)
Doped perovskite oxides with the general formula of AxA′1?xByB′1?yO3 have been extensively exploited as the cathode materials of solid oxide fuel cells (SOFCs), but the performance at low‐to‐medium temperatures still needs improvement. BaCo0.4Fe0.4Zr0.1Y0.1O3?δ (BCFZY) has been recently reported to show promising oxygen reduction reaction (ORR) activity under SOFCs' operating conditions. Here, it is reported that the activity of BCFZY can be further boosted via introducing a slight B‐site cation deficiency into the oxide lattice, and such an improvement is assigned to an increase in oxygen mobility that brings enhancement in both surface exchange and bulk diffusion kinetics. Specifically, materials with the nominal composition of Ba(Co0.4Fe0.4Zr0.1Y0.1)0.975O3?δ and Ba(Co0.4Fe0.4Zr0.1Y0.1)0.95O3?δ show significantly improved activity for ORR at reduced temperatures with the area specific resistances of 0.011 and 0.024 Ω cm2 at 600 °C, as a comparison of 0.042 Ω cm2 for the cation stoichiometric BCFZY. Excessive B‐site deficiencies, however, lead to the formation of impurity phases, which cause a block for charge transfer and, consequently, a reduction in electrode performance. Introducing a B‐site cation deficiency is a promising way to optimize the activity of perovskite oxides for ORR at reduced temperatures, but the degree of deficiency shall be carefully tuned. 相似文献
19.
Structural characterization of Er3+,Yb3+‐doped Gd2O3 phosphor,synthesized using the solid‐state reaction method,and its luminescence behavior
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We report the synthesis and structural characterization of Er3+,Yb3+‐doped Gd2O3 phosphor. The sample was prepared using the conventional solid‐state reaction method, which is the most suitable method for large‐scale production. The prepared phosphor sample was characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermoluminescence (TL), photoluminescence (PL) and CIE techniques. For PL studies, the excitation and emission spectra of Gd2O3 phosphor doped with Er3+ and Yb3+ were recorded. The excitation spectrum was recorded at a wavelength of 551 nm and showed an intense peak at 276 nm. The emission spectrum was recorded at 276 nm excitation and showed peaks in all blue, green and red regions, which indicate that the prepared phosphor may act as a single host for white light‐emitting diode (WLED) applications, as verified by International de I'Eclairage (CIE) techniques. From the XRD data, the calculated average crystallite size of Er3+ and Yb3+‐doped Gd2O3 phosphor is ~ 38 nm. A TL study was carried out for the phosphor using UV irradiation. The TL glow curve was recorded for UV, beta and gamma irradiations, and the kinetic parameters were also calculated. In addition, the trap parameters of the prepared phosphor were also studied using computerized glow curve deconvolution (CGCD). Copyright © 2015 John Wiley & Sons, Ltd. 相似文献