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Öğe Comparison of thermoluminescence characteristics of undoped and europium doped YAl3(BO3)4 phosphor synthesized by combustion method: Anomalous heating rate, dose response and kinetic analyses(Pergamon-Elsevier Science Ltd, 2023) Kaynar, Umit H.; Oglakci, M.; Bulcar, K.; Benourdja, S.; Bakr, M.; Ayvacikli, M.; Canimoglu, A.In this study, undoped and YAl3(BO3)(4) phosphors doped with Eu3+ at varying concentrations (x = 0.5 to 7 wt%) produced by a combustion process have been thoroughly examined by using the X-ray diffraction (XRD) and thermoluminescence (TL) techniques. The crystallized phosphors were confirmed by XRD analysis, and its crystal structure was examined. XRD analyses of the synthesized phosphor is in accordance with ICSD File No 96-152-6006. TL glow curve of undoped sample produced three glow peaks located at 80 degrees C, 240 degrees C, and 360 degrees C with a heating rate of 2 degrees Cs-1 whilst Eu3+ doped one appears at 90 degrees C, 230 degrees C, and 390 degrees C. The undoped example complied with the theory as expected, namely, as the heating rate increased, the TL glow curve shifted towards lower temperatures and decreased in intensity. However, an anomalous change was observed in the sample with Eu3+ additive. The experimental findings from the dose-response of YAl3(BO3)(4):0.5 wt%Eu3+ demonstrate that the intensity of TL provided by the total area under glow curves has an acceptable linearity (r(2):0.999) up to 100 Gy. The intensity of each maximum on the TL glow curve augments proportionally as the heating rate is augmented. Possible reasons of this behaviour are discussed. Various heating rate (VHR) methods (such as Hoogenstraaten's and Booth-Bohun-Parfianovitch) have also been used to estimate kinetic parameters (e.g., energy and frequency factor), which seem to be in good agreement with each other.Öğe Enhancing the blue luminescence behaviour of the Li co -doped novel phosphor ZnB 2 O 4: Tm 3+(Elsevier Science Sa, 2020) Kucuk, N.; Kaynar, Umit H.; Akca, S.; Alajlani, Y.; Yin, L.; Wang, Y.; Garcia Guinea, J.[Abstract Not Available]Öğe Synthesis and photoluminescence characteristics of Dy incorporated MoO3 phosphor: Suppression concentration quenching(Pergamon-Elsevier Science Ltd, 2020) Ayvacikli, M.; Kaynar, Umit H.; Karabulut, Y.; Canimoglu, A.; Bakr, M.; Akca, S.; Can, N.A series of MoO3:Dy3+ phosphors have been synthesized via the gel-combustion method. The X-ray and photoluminescence (PL) emission spectra were employed to characterize the obtained phosphors. The prepared samples were characterized through XRD measurements and exhibited that Dy3+ ions can be successfully incorporated into the host material. The PL emission bands of Dy3+ doped MoO3 were observed at 486 nm, 574 nm and 666 nm which are assigned to the transitions of F-4(9/2) -> H-6(15/2), F-4(9/2) -> H-6(13/2) and F-4(9/2) -> H-6(11/2), respectively. Concentration quenching were largely taken into consideration as one of the crucial aspects limiting the application range of phosphors in today's modern world. An abnormal thermal quenching dependence was reported when Dy3+ ions were incorporated into MoO3 host matrix. In order to understand the origin of this beneficial behaviour, energy transfer processes occurring via radiative and nonradiative mechanisms were investigated to elucidate this suppression of the concentration quenching.
