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1.
Mechanoluminescence,thermoluminescence, photoluminescence studies on Ca3Y2Si3O12:RE3+ (RE3+ = Dy3+and Eu3+) phosphors
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Dy3+ and Eu3+ activated Ca3Y2Si3O12 phosphors were synthesized by the solid‐state synthesis method. The phosphors were characterized by X‐ray diffraction (XRD), mechanoluminescence (ML), thermoluminescence (TL) and photoluminescence (PL) to determine structure and luminescence. For ML glow curves, only one peak was observed, as only one type of luminescence centre was formed during irradiation. The Ca3Y2Si3O12:Dy3+ TL glow curve showed a single peak at 151.55°C and the Ca3Y2Si3O12:Eu3+ TL glow curve peaked at 323°C with a small peak at 192°C, indicating that two types of traps were activated. The trapping parameters for both the samples were calculated using Chen's peak shape method. Dy3+‐activated Ca3Y2Si3O12 showed emission at 482 and 574 nm when excited by a 351 nm excitation wavelength, whereas the Eu3+‐activated Ca3Y2Si3O12 phosphor PL emission spectra showed emission peaks at 613 nm, 591 nm, 580 nm when excited at 395 nm wavelength. When excited at 466 nm, prominent emission peaks were observed at their respective positions with very slight shifts. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
2.
Frequency up‐conversion (UC) emission from the Nd3+‐Yb3+/Nd3+‐Yb3+‐Li+ co‐doped gadolinium oxide (Gd2O3) phosphors prepared by the solution combustion technique in the visible range have been studied by using 980 nm near infrared (NIR) laser diode excitation. The crystalline structure and formation of the cubic phase has been confirmed with the help of X‐ray diffraction (XRD) studies. XRD peak shifts have been found towards the lower diffraction angle side in the case of the Nd3+‐Yb3+‐Li+ co‐doped phosphors. Surface morphology and particle size information have been observed by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analysis. Down‐conversion emission study under 351 nm excitation in the visible region for the Nd3+‐Yb3+/Nd3+‐Yb3+‐Li+ co‐doped phosphors has been performed. The UC emission bands lying in the green and red region arising from the Nd3+ ions have been enhanced by ~260 times, ~113 times due to incorporation of Li+ ions in the Nd3+‐Yb3+ co‐doped phosphors. Photometric characterization has been done for the Nd3+‐Yb3+/Nd3+‐Yb3+‐Li+ co‐doped phosphors. The present study suggests the capability of the synthesized phosphors in near‐infrared (NIR) to visible upconverter and luminescent device applications. 相似文献
3.
White‐ and blue‐light‐emitting dysprosium(III) and terbium(III)‐doped gadolinium titanate phosphors
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Here we report the synthesis and structural, morphological, and photoluminescence analysis of white‐ and blue‐light‐emitting Dy3+‐ and Tm3+‐doped Gd2Ti2O7 nanophosphors. Single‐phase cubic Gd2Ti2O7 nanopowders consist of compact, dense aggregates of nanoparticles with an average size of ~25 nm for Dy3+‐doped and ~50 nm for Tm3+‐doped samples. The photoluminescence results indicated that ultraviolet (UV) light excitation of the Dy3+‐doped sample resulted in direct generation of white light, while a dominant yellow emission was obtained under blue‐light excitation. Intense blue light was obtained for Tm3+‐doped Gd2Ti2O7 under UV excitation suggesting that this material could be used as a blue phosphor. 相似文献
4.
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
5.
Photoluminescence and thermoluminescence properties of Eu2+ doped and Eu2+,Dy3+ co‐doped Ba2MgSi2O7 phosphors
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In this work, we report the preparation, characterization, comparison and luminescence mechanisms of Eu2+‐doped and Eu2+,Dy3+‐co‐doped Ba2MgSi2O7 (BMSO) phosphors. Prepared phosphors were synthesized via a high temperature solid‐state reaction method. All prepared phosphors appeared white. The phase structure, particle size, and elemental analysis were analyzed using X‐ray diffraction (XRD), transmission electron microscopy (TEM) and energy‐dispersive X‐ray (EDX) analysis. The luminescence properties of the phosphors were investigated by thermoluminescence (TL) and photoluminescence (PL). The PL excitation and emission spectra of Ba2MgSi2O7:Eu2+ showed the peak to be around 381 nm and 490 nm respectively. The PL excitation spectrum of Ba2MgSi2O7:Eu2+Dy3+ showed the peak to be around 341 nm and 388 nm, and the emission spectrum had a broad band around 488 nm. These emissions originated from the 4f6 5d1 to 4f7 transition of Eu2+. TL analysis revealed that the maximum TL intensity was found at 5 mol% of Eu2+ doping in Ba2MgSi2O7 phosphors after 15 min of ultraviolet (UV) light exposure. TL intensity was increased when Dy3+ ions were co‐doped in Ba2MgSi2O7:Eu2+ and maximum TL intensity was observed for 2 mol% of Dy3+. TL emission spectra of Ba1.95MgSi2O7:0.05Eu2+ and Ba1.93MgSi2O7:0.05Eu2+,0.02Dy3+ phosphors were found at 500 nm. TL intensity increased with UV exposure time up to 15 min, then decreased for the higher UV radiation dose for both Eu doping and Eu,Dy co‐doping. The trap depths were calculated to be 0.54 eV for Ba1.95MgSi2O7:0.05Eu2+ and 0.54 eV and 0.75 eV for Ba1.93MgSi2O7:0.05Eu2+,0.02Dy3+ phosphors. It was observed that co‐doping with small amounts of Dy3+ enhanced the thermoluminescence properties of Ba2MgSi2O7 phosphor. Copyright © 2016 John Wiley & Sons, Ltd. [Correction added on 5 April 2016, after first online publication: The following parts of the abstract have been edited for consistency. '4f65d1' has been corrected to '4f6 5d1', '4f7' has been corrected to '4f7', 'Ba1.95' has been corrected to 'Ba1.95' and 'Ba1.93' has been corrected to 'Ba1.93' respectively.] 相似文献
6.
Photoluminescence (PL) and thermoluminescence (TL) properties of rare earth (RE) ion (RE = Dy3+, Sm3+, Ce3+, Tb3+) activated microcrystalline BaMgP2O7 phosphors are presented in this work. Non‐doped and doped samples of BaMgP2O7 were prepared using a solid state diffusion method and characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), PL and TL. The XRD measurement confirmed the phase purity of the BaMgP2O7 host matrix. The average particle size was found through SEM measurement to be around 2 μm. All activators using the PL technique displayed characteristic excitation and emission spectra that corresponded to their typical f → f and f → d transitions respectively. Thermoluminescence measurements showed that BaMgP2O7:RE (RE = Dy3+, Sm3+, Tb3+, Ce3+) and co‐doped BaMgP2O7:Ce3+,Tb3+ phosphors have also TL behaviour. 相似文献
7.
The structural and optical properties of commercially obtained Y3Al5O12:Ce3+ phosphor were investigated by replacing Al3+ with Ga3+ and Y3+ with Gd3+ in the Y3Al5O12:Ce3+ structure to form Y3(Al,Ga)5O12:Ce3+ and (Y,Gd)3Al5O12:Ce3+. X‐Ray diffraction (XRD) results showed slight 2‐theta peak shifts to lower angles when Ga3+ was used and to higher angles when Gd3+ was used, with respect to peaks from Y3Al5O12:Ce3+ and JCPDS card no. 73–1370. This could be attributed to induced crystal‐field effects due to the different ionic sizes of Ga3+ and Gd3+ compared with Al3+ and Y3+. The photoluminescence (PL) spectra showed broad excitation from 350 to 550 nm with a maximum at 472 nm, and broad emission bands from 500 to 650 nm, centred at 578 nm for Y3Al5O12:Ce3+ arising from the 5d → 4f transition of Ce3+. PL revealed a blue shift for Ga3+ substitution and a red shift for Gd3+ substitution. UV–Vis showed two absorption peaks at 357 and 457 nm for Y3Al5O12:Ce3+, with peaks shifting to 432 nm for Ga3+ and 460 nm for Gd3+ substitutions. Changes in the trap levels or in the depth and number of traps due to Ce3+ were analysed using thermoluminescence (TL) spectroscopy. This revealed the existence of shallow and deep traps. It was observed that Ga3+ substitution contributes to the shallowest traps at 74 °C and fewer deep traps at 163 °C, followed by Gd3+ with shallow traps at 87 °C and deep traps at 146 °C. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
8.
Sr2ZnWO6:Eu3+,Bi3+,Li+: a potential white‐emitting phosphor for near‐ultraviolet white light‐emitting diodes
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Yuanyuan Ma Weiguang Ran Weina Li Chunyan Ren Haiyan Jiang Jinsheng Shi 《Luminescence》2016,31(3):665-670
A series of Sr2ZnWO6 phosphors co‐doped with Eu3+, Bi3+ and Li+ were prepared using the Pechini method. The samples were tested using X‐ray diffraction and luminescence spectroscopy. The results show that the samples can be effectively excited by near‐ultraviolet (UV) and UV light. The introduction of Bi3+ and Li+ significantly enhances the fluorescence emission of Sr2ZnWO6:Eu3+ and changes the light emitted by the phosphors from bluish‐green to white. When excited at 371 nm, Sr2–x–zZn1–yWO6:xEu3+,yBi3+,zLi+ (x = 0.05, y = 0.05, z = 0.05, 0.1 and 0.15) samples emit high‐performance white light. Intense red–orange emission is also observed when excited by UV light. The obtained phosphor is a potential white‐emitting phosphor that could meet the needs of excitation sources with near‐UV chips. In addition, this phosphor might have promising application as a red–orange emitting phosphor for white light‐emitting diodes based on UV light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
Thermoluminescence and photoluminescence studies on γ‐ray‐irradiated Ce3+,Tb3+‐doped potassium chloride single crystals
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Single crystals of KCl doped with Ce3+,Tb3+ were grown using the Bridgeman–Stockbarger technique. Thermoluminescence (TL), optical absorption, photoluminescence (PL), photo‐stimulated luminescence (PSL), and thermal‐stimulated luminescence (TSL) properties were studied after γ‐ray irradiation at room temperature. The glow curve of the γ‐ray‐irradiated crystal exhibits three peaks at 420, 470 and 525 K. F‐Light bleaching (560 nm) leads to a drastic change in the TL glow curve. The optical absorption measurements indicate that F‐ and V‐centres are formed in the crystal during γ‐ray irradiation. It was attempted to incorporate a broad band of cerium activator into the narrow band of terbium in the KCl host without a reduction in the emission intensity. Cerium co‐doped KCl:Tb crystals showed broad band emission due to the d–f transition of cerium and a reduction in the intensity of the emission peak due to 5D3–7Fj (j = 3, 4) transition of terbium, when excited at 330 nm. These results support that energy transfer occurs from cerium to terbium in the KCl host. Co‐doping Ce3+ ions greatly intensified the excitation peak at 339 nm for the emission at 400 nm of Tb3+. The emission due to Tb3+ ions was confirmed by PSL and TSL spectra. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
10.
Extraction of Y2O3:Cr3+ nanophosphor by eco‐friendly approach and its suitability for white light‐emitting diode applications
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J. B. Prasanna Kumar G. Ramgopal D. V. Sunitha B. Daruka Prasad H. Nagabhushana Y. S. Vidya K. S. Anantharaju S. C. Prashantha S. C. Sharma K. R. Prabhakara 《Luminescence》2017,32(3):414-424
Cr3+‐doped Y2O3 (0.5–9 mol%) was synthesized by a simple solution combustion method using Aloe vera gel as a fuel/surfactant. The final obtained product was calcined at 750°C for 3 h, which is the lowest temperature reported so far for the synthesis of this compound. The calcined product was confirmed for its crystallinity and purity by powder X‐ray diffraction (PXRD) studies which showed a single‐phase nano cubic phosphor. The particles size estimated by Scherrer formula was in the range of 6–19 nm. The UV–vis spectra showed absorption bands at 198, 272 and 372 nm having band gap energy in the range 4.00–4.26 eV. In order to investigate the possibility of its use in white light emitting display applications, the photoluminescence properties of Cr3+‐doped Y2O3 nanophosphors were studied at an excitation wavelength in the near ultraviolet (UV) light region (361 nm). The emission spectra consisted of emission peaks in the blue (4F9/2 → 6H15/2), orange (4F9/2 → 6H13/2) and red (4F9/2 → 6H11/2) regions. The CIE coordinates (0.33, 0.33) lie in the white light region. Hence Y2O3:Cr3+ can be used for white light‐emitting diode (LED) applications. 相似文献
11.
Monali R.Kadukar S. J. Dhoble A. K. Sahu V. Nayar S. Sailaja B. Sudhakar Reddy 《Luminescence》2017,32(2):159-170
This article reports on the luminescence properties of rare earth (Dy3+ and Tm3+)ions doped SrGa2Si2O8 phosphor were studied. SrGa2Si2O8phosphors weresynthesizedby employing solid state reaction method.From the measured X‐ray diffraction (XRD) pattern of the samplemonoclinic phase structure has been observed. Thermoluminescenceand Mechanoluminescence properties of the γ‐ray irradiated samples have been studied. Photoluminescence spectra of Dy3+ activated SrGa2Si2O8phosphor has been measured with an excitation wavelength at 348 nm,and it shows two emission bands at 483 and 574 nm due to 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions respectively. Whereas the photoluminescence spectra of Tm3+ activated SrGa2Si2O8 phosphor has been measured with an excitation wavelength at 359 nm and it exhibits two emission bands at 454 and 472 nm due to 1D2 → 3F4 and1G4 → 3H6 transitions respectively. In thermoluminescence study, γ‐irradiatedthermoluminescence glow curve of SrGa2Si2O8:Dy3+ phosphor shows two well defined peaks at 293 °C (peak1)and 170 °C (peak2) whereas thermoluminescence glow curve of SrGa2Si2O8:Tm3+ phosphor shows peaks at 292 °C (peak1) and 184 °C (peak2) indicating that two sets of traps are being activated within the particular temperature range and the trapping parameters associated with the prominent glow peaks of SrGa2Si2O8:Dy3+ and SrGa2Si2O8:Tm3+ are calculated using Chen's peak shape and initial rise method.From the Mechanoluminescence study, only one glow peak has been observed. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
Thermoluminescence (TL) materials are widely used in radiation measurements. The best‐known applications of TL materials are in the dosimetry of ionizing radiation, and in CTV screen phosphors, scintillators, X‐ray laser materials, etc. The TL glow curve and its kinetic parameters for annealed LaPO4 at different constant temperatures and for Dy3+‐doped LaPO4 phosphors irradiated by gamma‐rays are reported here. The samples were irradiated using a 60Co gamma‐ray source at a dose of 10 Gy and the heating rate used for TL measurements was 5ºC/s. The samples were characterized using X‐ray diffraction (XRD), Fourier transform infrared, transmission electron microscopy and TL techniques. The XRD pattern shows that the prepared phosphor has a good crystalline structure with an average crystallite size of ~ 18 nm. The samples show good TL peaks for 0.05, 0.1 and 0.2 mole % doping concentrations of Dy3+ ions and anneal above 400ºC. The TL glow curve characteristics of annealed LaPO4 and Dy3+‐doped LaPO4 were analyzed and trapping parameters calculated using various methods. All TL glow curves obey the second‐order kinetics with a single glow peak, which reveals that only one set of trapping parameter is set for a particular temperature. The TL sensitivity was found to depend upon the annealing temperature and Dy3+ doping concentration. The prepared sample may be a new nano phosphor and be useful in TL dosimetry. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
13.
Rare‐earth ions play an important role in eco‐friendly solid‐state lighting for the lighting industry. In the present study we were interested in Eu3+ ion‐doped inorganic phosphors for near ultraviolet (UV) excited light‐emitting diode (LED) applications. Eu3+ ion‐activated SrYAl3O7 phosphors were prepared using a solution combustion route at 550°C. Photoluminescence characterization of SrYAl3O7:Eu3+ phosphors showed a 612 nm emission peak in the red region of the spectrum due to the 5D0→7F2 transition of Eu3+ ions under excitation at 395 nm in the near‐UV region and at the 466 nm blue excitation wavelength. These red and blue emissions are supported for white light generation for LED lighting. Structure, bonding between each element of the sample and morphology of the sample were analysed using X‐ray diffraction (XRD) and scanning electron microscopy (SEM), which showed that the samples were crystallized in a well known structure. The phosphor was irradiated with a 60Co‐γ (gamma) source at a dose rate of 7.2 kGy/h. Thermoluminescence (TL) studies of these Eu3+‐doped SrYAl3O7 phosphors were performed using a Nucleonix TL 1009I TL reader. Trapping parameters of this phosphor such as activation energy (E), order of kinetics (b) and frequency factor (s) were calculated using Chen's peak shape method, the initial rise method and Ilich's method. 相似文献
14.
Luminescence properties of Tm3+ ions single‐doped YF3 materials in an unconventional excitation region
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According to the spectral distribution of solar radiation at the earth's surface, under the excitation region of 1150 to 1350 nm, the up‐conversion luminescence of Tm3+ ions was investigated. The emission bands were matched well with the spectral response region of silicon solar cells, achieved by Tm3+ ions single‐doped yttrium fluoride (YF3) phosphor, which was different from the conventional Tm3+/Yb3+ ion couple co‐doped materials. Additionally, the similar emission bands of Tm3+ ions were achieved under excitation in the ultraviolet region. It is expected that via up‐conversion and down‐conversion routes, Tm3+‐sensitized materials could convert photons to the desired wavelengths in order to reduce the energy loss of silicon solar cells, thereby enhancing the photovoltaic efficiency. 相似文献
15.
Jitender Kumar Shalendra Kumar Chander Shekhar Ranjeet Brajpuriya Ankush Vij 《Luminescence》2022,37(3):472-478
This article presents the effect of europium (Eu) doping on the thermoluminescence (TL) of ultraviolet (UV-254 nm) and gamma irradiated triclinic Mg2B2O5 nanophosphors. The diffuse reflectance predicts slight decrease in band gap from 5.18 to 4.99 eV with increasing Eu (1%, 3%, and 5%) content in Mg2B2O5. The TL glow curves of UV irradiated samples comprised of a main peak around 500 K with weak intensity peak/shoulders in low temperature region. Interestingly Eu (3%) doped Mg2B2O5 shows maximum TL intensity with suppression of low temperature shoulder peaks and almost linear UV dose dependent TL response. However, in the case of gamma irradiated Eu (1% and 3% doped) samples, TL glow curve comprises of a main peak around 425–445 K and closely lying peak around 500–515 K with relatively lesser intensity. In case of Eu (5%) doped samples, TL peak around 508 K starts dominating over peak around 425 K. TL of both UV and gamma irradiated samples showed the presence of various deep and shallow defect states within the bandgap of materials having different kinetic parameters, which were determined using TLanal software based on Kiti's general order equation. The present study shows that Eu doped Mg2B2O5 nanophosphors can be tuned for UV and gamma dosimetry. 相似文献
16.
Cerium‐doped Sr4Al14O25 phosphor is prepared using a single‐step combustion synthesis and its X‐ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and thermoluminescence (TL) properties are characterized. XRD reveals the formation of the desired phase in the prepared sample. SEM micrographs of the prepared Sr4Al14O25 phosphor show that the particle size is 10 µm. The prepared Sr4Al14O25, along with Sr4Al14O25:Cex (x = 0.5–5 mol%) shows a PL emission peak at 314 nm under UV excitation of 262 nm wavelength due to 5d → 4f transition. The phosphor is suitable for higher concentrations of Ce ions. The TL glow peak reveals three clearly visible distinct peaks at temperatures around 130, 231 and 336ºC. The three peaks are separated by deconvolution and kinetic parameters calculated using Chen's peak shape method. The calculation shows that the reaction follows second‐order kinetics with activation energy (E) values of 0.52, 0.81 and 1.12 eV, and frequency factor (s) values of 5.58 × 105, 4.53 × 107 and 4.57 × 108 s‐1 for the three individual peaks. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
17.
Yu‐Guo Yang Xu‐Ping Wang Bing Liu Yuan‐Yuan Zhang Xian‐Shun Lv Jing Li Lei Wei Hua‐Jian Yu Yanyan Hu Hua‐Di Zhang 《Luminescence》2020,35(4):580-585
Dy3+‐doped Y3Al5O12 phosphors were prepared at a relatively low temperature using molten salt synthesis. The phase of the prepared Dy3+‐doped Y3Al5O12 phosphors was confirmed using X‐ray powder diffraction. Results indicated that Dy3+ doping did not change the Y3Al5O12 phase. Following excitation at 352 nm, emission spectra of the Dy3+‐doped Y3Al5O12 phosphors consisted of blue, yellow, and red emission bands. The influence of Dy3+ concentration and excitation wavelength on emission was investigated. The ratio of yellow light to blue light varied with change in Dy3+ doping concentration, due to changes in the structure around Dy3+. Emission intensities also changed when the excitation wavelength was changed. This variation is luminescence generated a system for tunable white light for Dy3+‐doped Y3Al5O12 phosphors. 相似文献
18.
Ísis F. Manali Lucas C.V. Rodrigues Adriano H. Braga Douglas Galante Vernica C. Teixeira 《Luminescence》2020,35(4):456-465
Luminescent nanoparticles of Y2O3 doped with europium (Eu) and/or titanium (Ti) were synthesized using modified sol–gel routes. The crystalline cubic phase was confirmed using X‐ray powder diffraction (XRD). Particle morphology and size were evaluated using scanning and transmission electron microscopy. High‐resolution transmission electron microscopy showed that the synthesis method affected the average particle size and the Fourier transform of the images showed the lattice plane distances, indicating that the samples presented high crystallinity degree in accordance with the XRD pattern. The Ti valence was investigated using X‐ray absorption near edge spectroscopy and the tetravalent form was the dominant oxidizing state in the samples, mainly in Eu and Ti co‐doped Y2O3. Optical behaviour was investigated through X‐ray excited optical luminescence and photoluminescence under ultraviolet–visible (UV–vis) and vacuum ultraviolet (VUV) excitation. Results indicated that Eu3+ is the emitting centre in samples doped with only Eu and with both Eu and Ti with the 5D0→7F2 transition as the most intense, indicating Eu3+ in a noncentrosymmetric site. Finally, in the Eu,Ti‐doped Y2O3 system, Ti3+ (or TiIV) excitation was observed but no Ti emission was present, indicating a very efficient energy transfer process from Ti to Eu3+. These results can aid the development of efficient nanomaterials, activated using UV, VUV, or X‐rays. 相似文献
19.
Synthesis and thermoluminescence characterizations of Sr2B5O9Cl:Dy3+ phosphor for TL dosimetry
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The photoluminescence (PL) and thermoluminescence (TL) displayed by Dy‐activated strontium haloborate (Sr2B5O9Cl) were studied. A modified solid‐state reaction was employed for the preparation of the phosphor. Photoluminescence spectra showed blue (484 nm) and yellow (575 nm) emissions due to incorporation of Dy3+ into host matrix. The Dy‐doped (0.5 mol%) Sr2B5O9Cl was studied after exposure to γ‐irradiation and revealed a prominent glow curve at 261°C with a small hump around 143°C indicating that two types of traps were generated. The glow peak at the higher temperature side (261°C) was more stable than the lower temperature glow peak. The TL intensity was 1.17 times less than that of the standard CaSO4:Dy thermoluminescence dosimetry (TLD) phosphor, the phosphor showed a linear dose–response curve for different γ‐ray irradiation doses (0.002–1.25 Gy) and fading of 5–7% was observed for higher temperature peaks upon storage. Trapping parameters and their estimated error values have been calculated by Chen's peak shape method and by the initial rise method. Values of activation energies estimated by both these techniques were comparable. The slight difference in activation energy values calculated by Chen's peak shape method indicated the formation of two kinds of traps Furthermore, slight differences in frequency values are due to various escaping and retrapping probabilities. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
20.
In this study, Li6Y1–xEux(BO3)3 phosphor was successfully synthesized using a modified solid‐state diffusion method. The Eu3+ ion concentration was varied at 0.05, 0.1, 0.2, 0.5 and 1 mol%. The phosphor was characterized for phase purity, morphology, luminescent properties and molecular transmission at room temperature. The XRD pattern suggests a result closely matching the standard JCPDS file (#80‐0843). The emission and excitation spectra were followed to discover the luminescence traits. The excitation spectra indicate that the current phosphor can be efficiently excited at 395 nm and at 466 nm (blue light) to give emission at 595 and 614 nm due to the 5D0 → 7Fj transition of Eu3+ ions. Concentration quenching was observed at 0.5 mol% Eu3+ in the Li6Y1–xEux(BO3)3 host lattice. Strong red emission with CIE chromaticity coordinates of phosphor is x = 0.63 and y = 0.36 achieved with dominant red emission at 614 nm the 5D0 → 7 F2 electric dipole transition of Eu3+ ions. The novel Li6Y1–xEux(BO3)3 phosphor may be a suitable red‐emitting component for solid‐state lighting using double‐excited wavelengths, i.e. near‐UV at 395 nm and blue light at 466 nm. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献