Papers by Keyword: Luminescence

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Authors: Rui Lin, Gu Qiao Ding, Peng He, Jing Chen
Abstract: A facile method is proposed to synthesize carbon quantum dots (C-dots) from citric acid using concentrated sulfuric acid as carbonization reagents with temperature below 100 °C during the whole process. The prepared C-dots has a Gaussian distribution in its lateral size with the average value around 6.37 nm. High quality of the C-dots is revealed through the optical performances such as sharp band-edge absorption, typical absorption peak and nearly excitation-independent blue emissions. Further, the pH condition is found to have correlation on the strong and stable photoluminescence property.
Authors: Si Hua Wang, Zhi Gang Liu, Qiao Wang, Li Rong Yang, Feng Feng Li, Shou Wu Yu, Xiao Qing Liu, Peng Zhou, Xiao Xin Feng
Abstract: Luminescent Ln3+ (Ce3+, Tb3+) doped hydroxyapatite (HAp: Ce, Tb) phosphors were successfully fabricated via the modified hydrothermal process. The structure, morphology, and luminescent properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectra respectively. The XRD results reveal that the obtained HAp: Ce, Tb phosphors show the characteristic peaks of hydroxyapatite in a hexagonal lattice structure and the import of Ce3+and Tb3+ causes small change in the crystalline structure and leads to the peaks shifting and declining. It is observed that the as-prepared luminescent samples exhibit nearly equiaxial morphology of dispersed particles about 50-150 nm in size. Under 254 nm UV radiation excitation, the phosphors demonstrate the characteristic 5D47F36 emission lines of Tb3+and the excitation of Tb3+ is mainly caused by the energy transfer from Ce3+. PL intensity of Tb3+ doped HAp remarkably strengthened with increment of Ce3+ concentration and reached the maximum at the concentration of 4 mol%.
Authors: Rui Jin Yu, Jin Young Park, Hyun Kyoung Yang, Byung Kee Moon, Byung Chun Choi, Jung Hyun Jeong
Abstract: A new deep red-emitting Mn2+-activated SrLaGa3S6O phosphor was first prepared by a solid-state reaction method. Their luminescence properties were investigated by photoluminescence excitation and emission spectra. The emission spectrum shows a broad band with an emission maximum at 668 nm under the host excitation of 340 nm. The full width at half maximum (FWHM) of the emission peak is about 83 nm. The CIE chromaticity coordinates (x = 0.673 and y = 0.312) shows that the phosphor emission is in the deep red region and were very near to the NTSC standard values for red. Since the excitation band of the phosphor lies in the near UV excitable region, giving a deep red emission, it can be used for applications in near UV phosphor converted white LED lighting and display devices.
Authors: Lin Yan Jia, Zhong Bao Shao, Yan Wen Tian
Abstract: The pure phase red phosphor yttrium borate doped with Eu3+ was prepared by a new solid state reaction named high temperature ball milling method. The phosphor was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and luminescence spectra. The results show that the single phase YBO3:Eu3+ phosphor was obtained at 600°C, which is obviously decreased in contrast to conventional solid state reaction method. The particles are approximately nanometer size with narrow distribution range and spherical morphology. In emission spectra, the strongest peak at 597nm is due to the transition 5D0→7F1 of Eu3+ ions under 394nm monitoring wavelength. The luminescent properties of YBO3:Eu3+ phosphor with 25 mol% doping concentration of Eu3+ is optimal.
Authors: Xiao Jun Wang, Xiao Chun Zhou
Abstract: Mg2SnO4 was adopted as the host material of a new red emitting phosphor. Lumin-escence properties of the europium-doped magnesium tin oxide prepared by the low temperature solid state reaction were investigated under 395nm excitation. Under 395 nm excitation, the Mg2SnO4: Eu phosphor exhibits novel red emission at about 613 nm which is assigned to the 5D0 → 7F2 electric – dipole transition. Furthermore, the emission transition 5D0 → 7F2 has been found to be more prominent over the normal orange emission transition 5D0 → 7F1.
Authors: Xin Mu Zhou, Yong Xiu Li
Abstract: Cd1-xZnxSiO3:0.01 Mn2+ phosphor was synthesized by sol-gel method. It was characterized by excitation, emission spectra and XRD. The luminescent properties show the phenomenon of energy transfer from the tetrahedral coordinated Mn2+ ion to the octahedral coordinated Mn2+ ion after exciting by ultraviolet light, which boost the performance of the phosphor. With the increasing of Zn2+ in Cd1-xZnxSiO3:0.01 Mn2+ phosphor, it was observed the excitation spectra broadened and a red shift in the emission spectra, which emission peak moved from 580nm to 589nm.
Authors: M.R. Sahar, Ezza Syuhada Sazali, Nurulhuda Mohammad Yusoff
Abstract: This presentation provides a panoramic overview of the recent progress in nanoglass plasmonics, challenges, excitement, applied interests and the future promises. Enhanced optical properties of rare earth (RE) doped glasses for sundry applications are current challenges in materials science and technology. Nanoparticles (NPs) dispersed up-converted (UC) glasses seem to be the ideal candidates in terms of both efficiency and large area coverage provided the absorption cross-section be enhanced. The glasses containing gold NPs (AuNPs) and silver NPs (AgNPs) doped with optimum concentration of RE ions are of particular interest to us. We report the influence of embedded NPs on the luminescence and absorbance characteristics of RE ions doped tellurite glass prepared by melt-quenching method. The absorption and emission spectra displays several prominent peaks corresponding to the transitions from the ground state to the excited states of RE ion. The observed efficient enhancement of up-conversion emissions and absorbance in the entire visible region is attributed to strong localized electric field in vicinity of NPs. Improvements of radiative emissions suggests that the proposed glasses are potential for the development of solid state lasers, color displays and nanophotonic devices.
Authors: I. Ostrovskii, O.A. Korotchenkov
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