MCBÜ Açıkerişim Sistemi :: Browsing by Author "Karabulut, Y"

Browsing by Author "Karabulut, Y"

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Determination of in-row seed distribution uniformity using image processing
Çakir, E; Aygün, I; Yazgi, A; Karabulut, Y
The objective of this study was to determine the seed distribution uniformity of seeding machines using a low sensitivity (maximum 300 frames per second (fps)) high-speed camera and image processing method for corn, cotton, and wheat seeds under laboratory conditions. For this purpose, a high-speed camera with 100, 200, and 300 fps was used to measure the seed drop from the seeding tube onto the sticky belt. Video images then were transferred to the image processing algorithm, from which seed distribution can be calculated. The calculated measurements were compared statistically with the measurements obtained from sticky belt tests. According to the results for determining corn and cotton seed spacing by high-speed camera, the camera was successful only for corn seeds. For cotton seeds, camera readings were significantly different from the readings from the sticky belt due to the fact that capturing the cotton seed trajectory was not sufficient compared to the corn seed trajectory. Measuring the wheat seed spacing by high-speed camera was impossible with lower speeds of the camera. Wheat kernels could not be captured successfully by the camera at speeds of 100 and 200 fps. Therefore, only 300 fps speed was used to measure the seed spacing of wheat.
Third-order optical nonlinearities of Cu and Tb nanoparticles in SrTiO3
Cetin, A; Kibar, R; Hatipoglu, M; Karabulut, Y; Can, N
Some results of optical and nonlinear-optical properties of Cu and Tb nanoparticles implanted in SrTiO3 (STO) crystal are presented. The non-resonant third-order optical nonlinearities have been investigated by degenerate four wave mixing (DFWM), pump-probe and Z-scan techniques using femtosecond laser pulses. (C) 2010 Elsevier B.V. All rights reserved.
Synthesis and competitive luminescence quenching mechanism of Ca3Al2O6Ln3+(Ln: Dy and Sm) phosphors
Bakr, M; Kaynar, ÜH; Ayvacikli, M; Benourdja, S; Karabulut, Y; Hammoudeh, A; Can, N
Sm3+ and Dy3+ activated Ca3Al2O6 phosphors were produced through a gel combustion method using Urea + beta-Alanine, Urea, and Urea + Glycine as fuels. The crystal structure and the phase purity of the obtained materials were characterized by X-ray powder diffraction (XRD). Ca3Al2O6 :Sm3+ phosphor shows characteristic emission lines (565 nm, 602 nm, 649 nm, and 714 nm) in the orange red region assigned to (4)G(5/2) -> H- 6(J) (J = 5/2, 7/2, 9/2, 11/2) transitions of Sm3+. The strongest peak is located at 602 nm. Emission spectra of Ca3Al2O6 :Dy3+ show that there are two dominant peaks centered at 480 nm and 573 nm emitting blue and yellow light. Optimum doping concentrations of Sm(NO3)(3) and Dy(NO3)(3) are 0.01 % and 0.03 %, respectively. The concentration quenching mechanism is verified to be a dipole-dipole interaction as the type of energy transfer among Sm3+-Sm3+ and Dy3+-Dy3+ ions. The critical distance is also calculated to be 24.19 angstrom and 16.77 angstrom, respectively.
Characterization and thermoluminescence behavior of beta irradiated NaBaBO3 phosphor synthesized by combustion method
Oglakci, M; Akça, S; Halefoglu, YZ; Dogan, T; Ayvacikli, M; Karabulut, Y; Topaksu, M; Can, N
NaBaBO3 host material was synthesized using the combustion method. In order to optimize the performance of the material, effects of sintering temperatures varying from 600 degrees to 1000 degrees C were investigated. The sintering temperature and dwell time were found to have pronounced effects on the pure NaBaBO3 material. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) techniques were used to confirm the phase formation and examine the surface morphology of the prepared powder material, respectively. TL behavior of NaBaBO3 was studied at various beta doses. It is seen that the sample exhibits well resolved TL glow peak at a peak temperature about 175 degrees C and corresponding TL intensity increases with the increasing beta dose. However, TL glow peak slightly shifts to lower temperature with the increasing beta dose level. This is the first TL report of a phosphor with a NaBaBO3 host. The TL kinetic parameters were estimated by the peak shape (PS) method and CGCD software. TL glow curves of NaBaBO3 consist of several traps and exhibited second order kinetics. A possible TL mechanism was also discussed using the energy level model. The obtained results can provide valuable knowledge related to the investigation of the intrinsic nature characteristics of NaBaBO3 in research fields pertaining to dosimetry.
Comparison study on SMC and grain-oriented laminated steel core for small-size axial flux permanent-magnet synchronous machines
Karabulut, Y; Mese, E; Ayaz, M; Aktas, S
This study aims to compare the soft magnetic composite (SMC) and grain-oriented (GO) steel stator axial flux permanent-magnet synchronous machine (AFPMSM) in terms of performance and iron losses. Stator cores are manufactured using both materials to perform experimental performance tests. The produced machines are designed for pump propulsion systems in left ventricular assist devices as an application area. The machines are modeled with several analytical equations, and iron losses and performance tests are carried out with AFPMSMs, finite element methods, and experimental setups. Our findings show that the torque density is higher in the GO steel stator AFPMSMs that can produce 15.07 percent more torque. GO steel material experimentally has 20.33 percent less iron loss as SMC material since the loss value per kilogram for SMC material is higher than that for GO steel. In addition, the saturation value of the SMC material is lower than that of the GO material according to the magnetic flux density value.
Influence of laser excitation power on temperature-dependent luminescence behaviour of Ce- and Tb-incorporated BaMgAl10O17 phosphors
Kaynar, ÜH; Kaynar, SC; Ayvacikli, M; Karabulut, Y; Souadi, GO; Can, N
BaMgAl10O17 (BAM) is a highly suitable host lattice for various rare earth ions with excellent luminescence properties in different spectral regions, including a strong photoluminescence (PL) emission from the visible spectral region. A new Ce- and Tb-incorporated BaMgAl10O17 phase was synthesized successfully using a wet combustion method and it was studied as a function of the temperature and laser excitation power. We further characterize the obtained phosphors with X-ray diffraction at room temperature. Different fuel/oxidant (f/o) ratios were introduced to investigate the optimum synthesis conditions for the BAM phosphors and optimum ratio was found out to be 8. The photoluminescence (PL) spectra were collected under the excitation light generated by a Nd:YLF pulse laser at 349 nm as the temperature was increased from 10 K to 300 K. A strong green emission of Tb3+ was observed in the green region of the spectrum due to the D-5(4)-> F-7(J) transition. We also observed a wide emission band from the Ce3+ ion in the wavelength range of 350-650 nm. The luminescence intensities of all phosphors exhibited different patterns with an increase in the temperature. We also evaluated how the PL spectrum of the rare earth-activated BAM host matrix shifts under various laser excitation powers. The PL intensity of Ce-activated BAM significantly shifted (similar to 30 A) to the blue region of the spectrum with an increase in the laser excitation power, however we did observed no shift forTb(3+) activated BAM. The present findings suggest that Tb-incorporated BaMgAl10O17 can be effective as a green phosphor candidate material with a wide range of applications.
Strong Visible and Near-Infrared Cathodoluminescence in Alkali Feldspar
Karabulut, Y; Canimoglu, A
In this study, cathodoluminescence (CL) spectroscopy at direct current and alternating current under the sample temperature condition of 40-293K using different modulation frequencies is presented for alkali feldspar from the Dartmoor granite (UK). These feldspars contain strain-controlled lamellar crypto- and microperthites that are cross-cut by strain-free deuteric microperthites. The CL spectra of the alkali feldspar at room and low temperature confirm that the observed emission peaked at similar to 460nm could be associated with Al-O--Al or Ti impurity centers, yellow emission similar to 560nm could be associated with the presence of the centers such as radiation-induced defect centers, and similar to 756nm emission could be associated with the Fe3+ impurity center on T-1 and T-2 sites. The consequence of their association is to produce different luminescence properties such as intensity, peak wavelength, and band shape.
Cathodoluminescence Response From Sanidine Feldspar
Karabulut, Y; Canimoglu, A; Can, N
In the present study, cathodoluminescence (CL) providing information about surface rather than bulk material reveals blue and red emissions within the sanidine feldspar from the Eifel Mountains, Germany. The emission line occurring in the blue region at about 450nm reflects Al-O--Al structural defects, although distribution maps of the major elements, including Si, Al, and K, do not display a clear correlation with the CL properties of the sanidine feldspar. Dominant emission being in the longer-visible wavelength region (red region) approximate to 730nm is assumed to be caused by Fe3+ activation attributed to Fe3+-Al3+ substitution. Much less is known about the spectral characteristic of the feldspar CL emission, and the application of an older luminescence technique yields encouraging results for the practical application of the feldspar identification.
Simulation Optimization for Transportation System: A Real Case Application
Akpinar, ME; Yildizel, SA; Karabulut, Y; Dogan, E
Simulation applications help decision makers to give right decisions to eliminate some problems such as: create a new firm, need some changes inside a factory; improve the process of a hospital etc. In this engineering simulation study, there are two points which are used by students to arrive at the University. Initial point is the train station and the final point is the arrival point. Students' transportation is provided with buses. The main problem is to decide the number of buses by taking number of student into consideration. To be able to solve this real-life application PROMODEL pack software is used.
Application for Tsallis thermostatistics to half-width method used in thermoluminescence glow peaks in analysis of thermal desorption spectra
Kayacan, O; Can, N; Karabulut, Y; Afsar, O
Several methods have been developed in the analysis of the thermoluminescence glow peaks, and in particular when applied to thermoluminescence (TL) dosimetry and TL dating of archaeological and geological minerals. Some of these methods are identical to those developed for the study of thermal desorption. Such a method is called half-width method where a shape factor is introduced. Recently TL decay and thermal desorption process have been studied using a nonextensive formalism, namely Tsallis thermostatistics. In the present work, we consider the half-width method because it is the easiest one to estimate the activation energy. Importantly, we give the generalized form of the activation energy for all order of kinetics. We also investigate the influence of the nonextensivity on the shape factor parameter and on the activation energy. (C) 2004 Elsevier B.V. All rights reserved.
Eu3+ and Dy3+ doped La2MoO6 and La2Mo2O9 phosphors: Synthesis and luminescence properties
Kaynar, ÜH; Kaynar, SC; Alajlani, Y; Ayvacikli, M; Karali, E; Karabulut, Y; Akca, S; Karali, T; Can, N
We report a detailed structural analysis and properties of the photoluminescence (PL) and thermoluminescence (TL) spectra of Eu3+ and Dy3+ incorporated into novel La2MoO6 and La2Mo2O9 phosphors synthesized successfully through gel combustion synthesis. The formation of a tetragonal phase and a cubic structure were verified for La2MoO6 and La2Mo2O9 phosphors via X-ray diffraction (XRD) studies. Dy doped samples exhibited blue and green emissions at 480 nm (F-4(9/2) -> H-6(15/2)) and 572 nm (F-4(9/2) -> H-6(13/2)), and also Eu doped samples showed a sharp emission peaks at 612 and 619 nm (D-5(0) -> F-7(2)) upon 349 nm pulse laser excitation. Peak shape (PS) technique was utilised to determine activation energy, frequency factor and order of kinetics associated with the main glow curves in undoped and Eu and Dy doped samples after X-ray irradiation. The present findings suggest that Eu and Dy incorporated La2MoO6 and La2Mo2O9 phosphors are highly auspicious candidates for applications in solid-state lighting.
Cathodoluminescence and photoluminescence properties of Dy doped La2CaB10O19 phosphor
Ayvacikli, M; Kaynar, ÜH; Karabulut, Y; Guinea, JG; Dogan, T; Can, N
In this study, we report a detailed analysis of the photoluminescence (PL) and cathodoluminescence (CL) properties of La2CaB10O19 (LCB) doped with Dy ion. Dy doped LCB materials were successfully synthesized using a sol-gel combustion method. Dy doped LCB has the monoclinic structure with lattice parameters a = 11.02067 angstrom, b = 6.55755 angstrom, c = 9.10541 angstrom and alpha = gamma = 90.00, and 13 = 91.49?. Under the excitation by a low voltage electron beam and pulse laser at 349 nm, the LCB:Dy3+ phosphor produces the characteristic emission bands of Dy3+ due to intra-configuration transitions of F-4(9/2) -> H-6(15/2) (480 nm, blue), F-4(9/2) -> H-6(13/2) (574 nm, yellow), F-4(9/2) -> H-6(11/2) (662 nm, red) and F-4(9/2) -> H-6(9/2) (752 nm, red). The concentration quenching phenomenon was observed in both CL and PL measurements and optimum doping concentration was estimated to be 2%. We suggest that the concentration quenching mechanism of intense yellow emission at 574 nm was attributed to dipole-dipole interaction for both CL and PL.
Solid state synthesis, characterization and optical properties of Tb doped SrSnO3 phosphor
Kotan, Z; Ayvacikli, M; Karabulut, Y; Garcia-Guinea, J; Tormo, L; Canimoglu, A; Karali, T; Can, N
In the present study, the structural and optical properties of SrSnO3 doped with Tb ions are reported. Novel SrSnO3:Tb3+ phosphors were conventionally synthesized using a solid state reaction process under a mildly reduced atmosphere (5% H-2 and 95% N-2). The crystal structures, morphologies and optical properties of the resultant materials have been characterised by experimental techniques such as X-ray Diffraction (XRD), Raman spectroscopy (RS), Photoluminescence (PL), Radioluminescence (RL) and Cathodoluminescence coupled to an ESEM (ESEM-CL). The new phosphor material has good crystallization without any impurity phases, which matches with the standard JCPDS files (No. 22-1442) from XRD analysis. The PL, RL and CL measurements taken at room temperature showed that the transitions of D-5(4) to F-7(J) (j = 6, 5, 4, 3) corresponding to the typical 4f -> 4f dipole forbidden intra-configurational transitions of Tb3+ are largely independent of the host material. The green emissions of the D-5(4) -> F-7(5) magnetic dipole transition at similar to 540 nm are predominant for three types of luminescence. PL emission spectra recorded in the temperature range from 10 K to 300 K were influenced by temperature. We report anomalies in the PL spectra of SrSnO3:Tb3+ compatible with a structural phase transition at 260 K while simultaneously exciting and cooling the sample. This work clearly confirms the existence of a phase transition discovered by Singh et al. in SrSnO3 at 270 K. (C) 2013 Elsevier B.V. All rights reserved.
Comparative studies on thermoluminescence characteristics of non-doped Mg2SiO4 prepared via a solid-state reaction technique and wet-chemical method: An unusual heating rate dependence
Dogan, T; Akça, S; Yüksel, M; Kucuk, N; Ayvacikli, M; Karabulut, Y; Canimoglu, A; Topaksu, M; Can, N
Magnesium orthosilicate (Mg2SiO4) was synthesized via a traditional solid-state reaction and a wet chemical route. This study primarily reported the thermoluminescence (TL) behavior of Mg2SiO4 host. X-ray diffraction pattern revealed that Mg2SiO4 exhibits orthorhombic structure matched with JCPDS card 900-6398. Dose response, reproducibility and trap parameters of TL glow curves were evaluated to clearly reveal TL features. Two TL glow peaks situated at 81 degrees C and 192 degrees C were monitored at a heating rate of 2 degrees Cs-1. We observed anomalous heating rate effect for the peak centered at 192 degrees C whilst TL intensity of the peak at 81 degrees C decreases with elevating heating rate. Trap depths of the electrons within the trap centers were found to be 1.04 +/- 0.01eV and 1.37 +/- 0.01eV for both methods using peak shape (PS) method. Distribution of trap centers was examined using the T-max - T-stop method and this case indicated that the glow curves consist of single TL peaks. The intensity of TL glow curves exhibited a good linear dose response under total area up to 20 Gy. A comparison of the two preparation techniques revealed that TL characteristics of this phosphor are partly dependent and Mg2SiO4 could be a promising material for dosimetric application. (C) 2019 Elsevier B.V. All rights reserved.
Synthesis and Luminescence Properties of Trivalent Rare-Earth Element-Doped Calcium Stannate Phosphors
Karabulut, Y; Ayvacikli, M; Canimoglu, A; Guinea, JG; Kotan, Z; Ekdal, E; Akyuz, O; Can, N
The phosphors of calcium stannate activated with individual trivalent rare-earth element (REE) ions (Neodymium III, Europium III, Terbium III, Dysprosium III, and Samarium III) were synthesized by high-temperature solid-state reaction (SSR), and their characterization and luminescent properties were investigated. The crystal structures and morphologies of the resultant materials were well characterized by experimental techniques such as X-ray powder diffraction (XRD) and environmental scanning electron microscopy (ESEM). The XRD results display that the rare-earths substitution of Calcium II does not change the structure of calcium stannate host. Obviously, the ESEM image exhibits that phosphors aggregate and their particles with irregular shape exist. The calcined powders of the Europium III, Neodymium III, Samarium III, Dysprosium III, and Terbium III ions doped in calcium stannate exhibits bright red, reddish orange, yellowish, orange white, and green light, respectively. Although there is some intrinsic emission ranging from UV to near-infrared (NIR) due to the host lattice, the dominant signals are from the rare-earth sites, with signals characteristic of the trivalent rare-earth states. The emission spectrum from undoped-calcium stannate phosphor is characterized by two broad bands centered at similar to 800 and similar to 950nm. The shapes of the emission bands are different for each dopant. The sharp emission properties show that the calcium stannate is a suitable host for rare-earth ion-doped phosphor material. Furthermore the influence of different rare-earth dopants, that is, Europium III, Neodymium III, Samarium III, Dysprosium III, and Terbium III, on thermally stimulated luminescence (TSL) of calcium stannate phosphor under the beta irradiation was discussed. Among these trivalent rare-earth-doped phosphors samarium-doped material showed maximum TSL sensitivity with favorable glow curve shape.
Preparation and characterization of Yttrium based luminescence phosphors
Muresan, LE; Ayvacikli, M; Guinea, JG; Canimoglu, A; Karabulut, Y; Can, N
Ce doped Yttrium aluminate modified by replacing different molar part of aluminium or gallium (Y(3)Al(5-x)GaxO(12)) and Yttrium silicate phosphors activated with Ce and Tb (Y2SiO5:Ce3+,Tb3+) were synthesized by solid state reaction and a gel combustion method, respectively. X-ray diffraction and Scanning electron microscope (SEM) techniques are used to identify their structures and morphologies. Luminescence characteristics are measured and spectroscopic data confirm that Y2SiO5:Ce3+, Tb3+ phosphors can be effectively excited upon UV excitation light and X-ray irradiation, resulting in intense blue and green emissions, respectively. This energy transfer takes place by means of a non-radiative process inside Ce3+-Tb3+ clusters formed in the host matrix. Tb3+ doped Y2SiO5 yields both blue emission D-5(3) -> F-7(j) (j = 3,4,5,6) and green emission D-5(4) -> F-7(J) (J = 3,4,5,6) of Tb3+. Y(3)Al(5-x)GaxO(12):Ce3+ phosphors exhibit a broad blue emission band originating from allowed 5d-4f transition of the Ce3+ ions under different excitation sources but the broad emission band shifts with increasing of Ga3+ content. This work presents a quantitative understanding of host material's on dopant's luminescence properties and thereby provides an optimization guideline, which is extremely demanding for the development of new luminescent materials. (C) 2017 Elsevier B.V. All rights reserved.
Cathodoluminescence and thermoluminescence of ZnB2O4:Eu3+ phosphors prepared via wet-chemical synthesis
Dogan, T; Tormo, L; Akca, S; Kucuk, N; Guinea, JG; Karabulut, Y; Ayvacikli, M; Oglakci, M; Topaksu, M; Can, N
In present work, a series of Eu doped zinc borate, ZnB2O4, phosphors prepared via wet chemical synthesis and their structural, surface morphology, cathodoluminescence (CL) and thermoluminescence (TL) properties have been studied. Phase purity and crystal structure of as-prepared samples are confirmed by X-ray diffraction measurements (XRD) and they were well consistent with PDF card No. 39-1126, indicating the formation of pure phase. The thermoluminescence (TL) behaviors of Eu activated ZnB2O4 host lattice are studied for various beta doses ranging from 0.1 to 10 Gy. The high-temperature peak of Eu activated sample located at 192 degrees C exhibited a linear dose response in the range of 0.1-10 Gy. Initial rise (IR) and peak shape (PS) methods were used to determine the activation energies of the trapping centres. The effects of the variable heating rate on TL behaviour of Eu activated ZnB2O4 were also studied. When excited using an electron beam induced light emission (i.e cathodoluminescence, CL) at room temperature (RT), the as-prepared phosphors generate reddish-orange color due to predominant emission peaks of Eu3+ ions located at 576-710 nm assigned to the D-5(0)-> F-7(J) (J=1,2,3, and 4) transitions. The maximum CL intensity for Eu3+ ions at 614 nm with transition D-5(0)-> F-7(2) was reached Eu3+ concentration of 5 mol%; quenching occurred at higher concentrations. Strong emission peak for Eu3+ ions at 614 nm with transition D-5(0)-> F-7(2) is observed. The CL experimental data indicate that ZnB2O4:Eu3+ phosphor as an orange-red emitting phosphor may be promising luminescence materials for the optoelectronic applications.
Synthesis and influence of ultrasonic treatment on luminescence of Mn incorporated ZnS nanoparticles
Cadis, AI; Muresan, LE; Perhaita, I; Munteanu, V; Karabulut, Y; Guinea, JG; Canimoglu, A; Ayvacikli, M; Can, N
Manganese (Mn) doping of ZnS phosphors was achieved by precipitation method using different ultrasound (US) maturation times. The structural and luminescence properties of the samples were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), photoluminescence (PL), and cathodoluminescence (CL). The real amount of manganese incorporated in ZnS lattice was calculated based on ICP-OES results. According with XRD patterns, the phase structure of ZnS:Mn samples is cubic. EDS spectra reveal deviations of the Mn dopant concentration from the target composition. Both 300 K PL and CL emission spectra of the Mn doped ZnS phosphors display intense orange emission at 590 and 600 nm, respectively, which is characteristic emission of Mn ion corresponding to a T-4(1) -> (6)A(1) transition. Both PL and CL spectra confirmed manganese is substitutionally incorporated into the ZnS host as Mn2+. However, it is suggested that the origin of broad blue emission around 400 nm appeared in CL is due to the radiative recombination at deep level defect states in the ZnS. The ultrasound treatment at first enhances the luminescent intensity by similar to 3 times in comparison with samples prepared by classical way. This study gives rise to an optimization guideline, which is extremely demanded for the development of new luminescent materials. (C) 2017 Elsevier B.V. All rights reserved.
Preparation and cathodoluminescence characteristics of rare earth activated BaAl2O4 phosphors
Benourdja, S; Kaynar, ÜH; Ayvacikli, M; Karabulut, Y; Guinea, JG; Canimoglu, A; Chahed, L; Can, N
Undoped and Pr, Sm and Tb activated BaAl2O4 phosphors have been synthesized by solid state reaction method and combustion method. The structure and morphological observation of the phosphor samples were monitored by X-ray powder diffraction (XRD) and environmental scanning electron microscope (ESEM) coupled to an energy dispersive X-ray spectrometer (EDS). The all diffraction peaks are well assigned to standard data card (PDF#17-306). Emission properties of the samples were explored using light emission induced by an electron beam (i.e cathodoluminescence, CL) at room temperature (RT). Undoped BaAl2O4 sample exhibits a broad defect emission from 300 to 500 nm from the aluminate defect centres. CL spectra recorded at room temperature display that the as-prepared BaAl2O4:Ln (Ln = Pr, Sm and Tb) phosphors exhibit different luminescence colors coming from different rare earth activator ions. The transition (4)G(5/2) -> H-6(7/2) located at 606 and 610 nm for Sm3+ can occur as hypersensitive transition having the selection rule Delta J = +/- 1. For the Tb3+ doped samples, they exhibit D-5(4) green line emissions. The proposed luminescent mechanisms of all doped rare earth ions are also discussed.
The role of calcination temperature on structural and luminescence behaviour of novel apatite-based Ca2Y 8(SiO4)6O2: Ce3+,Tb3+ phosphors
Perhaita, I; Muresan, LE; Silipas, DT; Borodi, G; Karabulut, Y; Guinea, JG; Ayvacikli, M; Can, N
A series of novel apatite-based Ca2Y8(SiO4)(6)O-2 phosphors doped with Ce3+ and Tb3+ were synthesized by a solid-state reaction method at different calcination temperatures and times. The comparative results of thermal analysis (TG-DTA), FTIR, X-ray diffraction (XRD) and environmental scanning electron microscope (ESEM) reveal that the firing temperature for Ca2Y (8)(SiO4)(6)O-2:Ce3+, Tb3+ was optimized to be 1200 degrees C. The systematic studies on the influences of thermal treatment conditions on photoluminescence (PL) and cathodoluminescence (CL) properties were also reported. The excitation spectra of Ca2Y8(SiO4)(6)O-2:Ce3+, Tb3+ exhibited one strong excitation band at 325 run. The PL and CL results indicated that the violet-blue emission intensities about 400 nm from the Ce3+ and efficient green emission at 544 nm from Tb3+ were highly dependent on the calcination conditions.

Browsing by Author "Karabulut, Y"

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