Abstract:The inefficient luminescence performance
of Ce3+ activated
glasses is primarily responsible for their commercial failure compared
to the Ce3+ activated crystalline materials that are widely
used as phosphors and scintillators. We observed that this behavior
is explicitly related to the intrinsic characteristics of the host
material. Here, we present a systematic study on Ce3+ luminescence
in amorphous borate glass and make a comparison with the well-known
polycrystalline Y3Al5O12:Ce3+ (YAG:Ce) phosphor. In bor… Show more
“…These biphasic ceramics demonstrate transparency from the visible up to the near infrared ranges (6 μm) and improved mechanical properties, especially higher hardness, compared to YAG single crystal and transparent ceramics. When doped by Ce 3+ , the YAG-Al 2 O 3 nanoceramic synthesized at 1100 °C shows a 87.5% quantum efficiency, which is comparable with commercial YAG:Ce 3+ fluorescent powders (75–90%) 35,36 . The combination of the high-performance mechanical and optical properties with the thermal stability of this YAG-Al 2 O 3 ceramic material, coupled to its facile room pressure preparation, opens great potential applications in wide optical fields such as jewellery, lenses, scintillators and phosphor converters for high-power white-light LED, and laser diodes, which require limited light scattering in the materials 37 .Fig.…”
Transparent crystalline yttrium aluminum garnet (YAG; Y3Al5O12) is a dominant host material used in phosphors, scintillators, and solid state lasers. However, YAG single crystals and transparent ceramics face several technological limitations including complex, time-consuming, and costly synthetic approaches. Here we report facile elaboration of transparent YAG-based ceramics by pressureless nano-crystallization of Y2O3–Al2O3 bulk glasses. The resulting ceramics present a nanostructuration composed of YAG nanocrystals (77 wt%) separated by small Al2O3 crystalline domains (23 wt%). The hardness of these YAG-Al2O3 nanoceramics is 10% higher than that of YAG single crystals. When doped by Ce3+, the YAG-Al2O3 ceramics show a 87.5% quantum efficiency. The combination of these mechanical and optical properties, coupled with their simple, economical, and innovative preparation method, could drive the development of technologically relevant materials with potential applications in wide optical fields such as scintillators, lenses, gem stones, and phosphor converters in high-power white-light LED and laser diode.
“…These biphasic ceramics demonstrate transparency from the visible up to the near infrared ranges (6 μm) and improved mechanical properties, especially higher hardness, compared to YAG single crystal and transparent ceramics. When doped by Ce 3+ , the YAG-Al 2 O 3 nanoceramic synthesized at 1100 °C shows a 87.5% quantum efficiency, which is comparable with commercial YAG:Ce 3+ fluorescent powders (75–90%) 35,36 . The combination of the high-performance mechanical and optical properties with the thermal stability of this YAG-Al 2 O 3 ceramic material, coupled to its facile room pressure preparation, opens great potential applications in wide optical fields such as jewellery, lenses, scintillators and phosphor converters for high-power white-light LED, and laser diodes, which require limited light scattering in the materials 37 .Fig.…”
Transparent crystalline yttrium aluminum garnet (YAG; Y3Al5O12) is a dominant host material used in phosphors, scintillators, and solid state lasers. However, YAG single crystals and transparent ceramics face several technological limitations including complex, time-consuming, and costly synthetic approaches. Here we report facile elaboration of transparent YAG-based ceramics by pressureless nano-crystallization of Y2O3–Al2O3 bulk glasses. The resulting ceramics present a nanostructuration composed of YAG nanocrystals (77 wt%) separated by small Al2O3 crystalline domains (23 wt%). The hardness of these YAG-Al2O3 nanoceramics is 10% higher than that of YAG single crystals. When doped by Ce3+, the YAG-Al2O3 ceramics show a 87.5% quantum efficiency. The combination of these mechanical and optical properties, coupled with their simple, economical, and innovative preparation method, could drive the development of technologically relevant materials with potential applications in wide optical fields such as scintillators, lenses, gem stones, and phosphor converters in high-power white-light LED and laser diode.
“…27 While for Ce 4+ , UV light will be absorbed efficiently by charge transfer transition of Ce 4+ with ligand anion (Ce 4+ -O 2− → Ce 4+(−) -O − ). 22,[28][29][30] Besides, CeO 2 is a very promising UV-absorbing material because of its wide band gap (3.37 eV), and it shows higher transparency in the visible light range compared to TiO 2 and ZnO. 11,28,[31][32][33][34][35][36] Although the absorption of Ce 4+ occured at a longer wavelength region than that of Ce 3+ in previous research, it is hard to distinguish the absorption of Ce 3+ and Ce 4+ in the UV region.…”
Section: Introductionmentioning
confidence: 97%
“…[21][22][23][24] Ce 3+ ions (4f 1 electron configuration) show characteristic absorption in the UV region and tunable emission due to allowed transitions between 4f and 5d j (j = 1-5) states. 22,25,26 However, the luminescence from Ce 3+ can be strongly deactivated by Ce 4+ in glass. 27 While for Ce 4+ , UV light will be absorbed efficiently by charge transfer transition of Ce 4+ with ligand anion (Ce 4+ -O 2− → Ce 4+(−) -O − ).…”
With thinning of the ozone layer, considerable attention has been paid to developing materials that block or reduce ultraviolet (UV) transmission. Here, bulk cerium doped glasses with relatively high transparency were successfully manufactured using the melt‐quenching method. The varied ratio of Ce3+ and Ce4+ in glasses could be deduced by optical properties in photoluminescence excitation, emission spectra, decay curves and absorption spectra. These glasses exhibit excellent UV‐blocking capacity due to the absorption of Ce3+ and Ce4+. Their outstanding physical and chemical stability have been demonstrated in the condition of high temperature, long‐term UV radiation, strong alkali solution and acetone. Hence, our cerium doped glasses are potentially attractive candidates in UV‐shielding device.
“…84,86,87 The second mode is true cases where different valence states of activators coexist. 88,89 This mode has been recently reported in Eu-doped SrliAl 3 N 4 and the Ce-doped green light-excitable SrMg 2 Al 2 N 4 . 90 The third mode is based on the 4f-5d crossing model that is illustrated in configuration coordinate diagrams.…”
Searching for narrow-band red-emitting and thermally stable phosphors is the ultimate strategy toward enhanced performance of phosphor converted light emitting diodes (pc-LED). The red emission is assured by the nitride host because of its relatively more covalent character than oxides and sulfides; however, the narrow emission is attributed to crystallographic, morphological, and electronic considerations. The symmetric coordination site ensures equal ligand effect in all direction fits well with the configuration of Eu 2+ f orbitals in the excited state, as observed in cuboid nitrides. Further, thermal stability is ascribed not only to suitable bandgap but more specifically, a relatively distant location of the lowest 5d level from the bottom of the conduction band (CB) that consequently entails high energy to quench excited electrons by exciting them further up to the CB. Modes toward the development of new nitride hosts with potentially narrow-band emission have been identified. A viewpoint on light-emitting diode (LED), backlighting, and laser lighting, which remains the most economically-rewarding phosphors application, is presented. Other exciting frontiers, such as agricultural illumination and persistent luminescence, maximize nitride systems that have other properties other than the stringent narrow-band red emission and excellent thermal stability required for the desired improvement of the mainstream LED application.
is a Critical Review in Electrochemical and Solid State Science and Technology (CRES 3 T). This article was reviewed by Anant Setlur (setlur@ge.com) and Jing Wang (ceswj@mail.sysu.edu.cn). This paper is part of the JSS Focus Issue on Visible and Infrared Phosphor Research and Applications.The discovery, development, and commercialization of phosphors are expected to satisfactorily fare with the benchmark set for phosphor converted-LEDs. First, the excitation wavelength of the phoshpors must be compatible with the blue LED pump, thereby emitting the desired colors and consequently generating white light. Second, the quantum efficiency should be high. Third, phosphor must have a high absorption rate in the LED range, which technically narrows the choices to those that are excitable through 4f → 5d, d → d, np → nd, and ns → np transitions. Fourth, it must have high thermal quenching temperature. Fifth, the inherent stability against moisture and continuous irradiation ensures the durability and longevity of the device. Sixth, a rational design must be presented for the synthesis conditions from the selection of starting materials, synthesis strategy, and costs to allow the smooth cross-over to eventual industrial-scale production.
1,2Tuning the phosphor photoluminescence requires a tunable phosphor and a set of strategies to introduce changes in intensity, emission wavelength, and full width at half-maximum (fwhm). Moreover, the following are of paramount consideration in tuning the phosphor photoluminescence. First, a clear understanding of crystal and local structures and the investigati...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
