Processing of transparent glass-ceramics by nanocrystallisation of LaF3

Hemono, Nicolás; Pierre, G.; Muñoz, Francisco; Pablos-Martín, A. de; Pascual, María J.; Durán, Alicia

doi:10.1016/j.jeurceramsoc.2009.05.013

Cited by 48 publications

(47 citation statements)

References 17 publications

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“…In addition, -energy dispersion X-ray (EDX) spectroscopy [145,200,123]; -X-ray fluorescence analysis and -flame photometry (FP) [159] are employed to determine chemical composition of synthesized glasses and glass ceramics.…”

Section: Properties Of Glass Ceramics and Methods Of Their Studyingmentioning

confidence: 99%

“…Thermal treatment of such glasses results in the appearance of these RF 3 species as primary crystalline nanophases [158,159]. However, much more frequently, rare earth trifluorides do not appear as a separate nanophase of this stoichiometric composition.…”

Section: Crystallization and Devitrification (Devitriheation) Of Glassesmentioning

confidence: 99%

“…Bocker et al [100] clearly showed that droplet phase separation is the initial step of the nano SrF 2 crystallization into silicate glass under thermal treatment. Hemono et al [159] and Pablos-Martin et al [167,25,265] studied the crystallization kinetics of LaF 3 nanocrystals in oxyfluoride SiO 2 -Al 2 O 3 -Na 2 O-LaF 3 glasses and came to the conclusion that phase separation in the glass body precedes crystallization and quenching of the melt produces homogeneous glass. Reheating of the aforementioned SiO 2 -Al 2 O 3 -Na 2 O-LaF 3 samples caused the appearance of the droplet-like glass surfases, the first one was enriched in LaF 3 , and the second phase contained more SiO 2 and Al 2 O 3 .…”

Section: Micro-liquationmentioning

confidence: 99%

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Transparent oxyfluoride glass ceramics

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Section: Properties Of Glass Ceramics and Methods Of Their Studyingmentioning

confidence: 99%

Section: Crystallization and Devitrification (Devitriheation) Of Glassesmentioning

confidence: 99%

Section: Micro-liquationmentioning

confidence: 99%

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Transparent oxyfluoride glass ceramics

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Journal of Fluorine Chemistry

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“…[ 3 ] Transparent polycrystalline ceramics are also an emerging class of optical materials such as gain media for ceramic lasers [ 4 ] (Nd:YAG), transparent body armor [ 5 ] (MgAl 2 O 4 ), and scintillators [ 6 ] (Lu 2 O 3 ). Few examples of transparent crystalline aluminate ceramics derived from high pressure and high temperature treatment of a glass precursor [ 7,8 ] or from direct and complete bulk glass crystallization synthesis atmosphere, [ 30 ] utilization and volatilization of corrosive elements like fl uorine [ 31 ] ) limit considerably their industrial applications. Germanate-based materials are thus of primary interest due to their excellent optical properties in both the visible and infrared ranges.…”

Section: Introductionmentioning

confidence: 99%

Tuneable Nanostructuring of Highly Transparent Zinc Gallogermanate Glasses and Glass‐Ceramics

Chenu

Véron

Genevois

et al. 2014

Advanced Optical Materials

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routes [ 9,10 ] have been recently reported. Technical challenges remain to produce these transparent ceramic materials (complicated and time-consuming procedures to avoid porosity, [ 11 ] limited compositions, segregation of doping agents, etc.). Many of these obstacles can be avoided via the use of glass-ceramic technology. [ 12 ] Therefore, the development of transparent glassceramics is of great interest for many promising optical applications [ 13 ] (solar concentrators, [ 14 ] optical memory media, [ 15 ] telescope mirrors, [ 16 ] amplifi ers, [ 17 ] electrooptical devices [ 18 ] ). Unlike single crystals and polycrystalline sintered ceramics, glass-ceramic materials offer considerable advantages such as a wider range of accessible chemical compositions, fabrication of complex shapes, and largescale production by fast and cost-effi cient glass-forming processes. The absence of porosity, control of the microstructure, and high transparency allow a large variety of optical glass-ceramics to be designed and commercialized.Glass-ceramic technology is generally based on the controlled crystallization of glass. [ 12 ] According to the Rayleigh-GansDebye [ 19 ] and Hendy theories, [ 20 ] the retention of transparency during glass crystallization typically requires a homogeneous distribution of nanoscale crystals in the glass-ceramic material to minimize light scattering. Nucleating agents (such as ZrO 2 and TiO 2 ) are thus often added in the parent glass to produce, by heat treatment, uniformly dispersed nanocrystals. [ 21 ] Nevertheless, a few exceptions with large crystal sizes (β-quartz- [ 16 ] and Na 2 O-CaO-SiO 2 -based glass-ceramics [ 22 ] ) have been reported, and their transparency is directly linked to a very small refractive index difference between the amorphous and crystalline phases. Much attention has been devoted to transparent silicate glass-ceramics, which often present low thermal expansion, thermal stability, and high transparency in both visible and near-infrared ranges. [ 12,16 ] However, silicatebased glass-ceramics present a high phonon energy, which considerably limits their transparency in the infrared range and therefore their applications in this domain. The development of oxyfl uoride [23][24][25][26] and chalcogenide [ 27,28 ] glass-ceramics has extended the transparency toward the infrared range. These materials offer a real alternative allowing access to applications in telecommunications [ 25,26,29 ] (up-conversion devices, waveguide amplifi ers), although their poor chemical durability and complex fabrication (synthesis under a controlled New nanostructured gallogermanate-based glass materials exhibiting high transparency in the visible and infrared regions are fabricated by conventional melt-quenching. These materials can accommodate wide oxide compositions and present nanoscale phase separation, in the form of droplets well separated from the germanate matrix. The size of the nanostructures can be tailored depending on the composition. A single heat treatment then allows select...

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“…The properties of the un-doped glass system have been extensively studied elsewhere (Bhattacharyya et al, 2009;Hemono et al, 2009;de Pablos-Martín et al, 2011).…”

Section: +mentioning

confidence: 99%

Transparent Oxyfluoride Nano-Glass Ceramics Doped with Pr3+ and Pr3+–Yb3+ for NIR Emission

et al. 2017

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Pr 3+-Yb 3+ co-doped oxyfluoride glasses and glass-ceramics (GCs) containing LaF3 nanocrystals have been prepared to obtain NIR emission of Yb 3+ ions upon Pr 3+ excitation in the blue region of the visible spectrum. Two different compositions have been tested: 0.1-0.5 Pr-Yb and 0.5-1 Pr-Yb, in addition to Pr 3+ singly doped samples. The crystallization mechanism of the nano-GCs was studied by differential thermal analysis revealing that it occurs from a constant number of nuclei, the crystal growth being limited by diffusion. High-resolution transmission microscopy demonstrated that phase separation acts as precursor for LaF3 crystallization and a detailed analysis of the chemical composition (EDXS) revealed the enrichment in RE 3+ ions inside the initial phase separated droplets, from which the LaF3 crystals are formed. The RE 3+ ions incorporation inside LaF3 crystals was also proved by photoluminescence measurements showing Stark splitting of the RE 3+ ions energy levels in the glass-ceramic samples. Lifetime measurements showed the existence of a better energy transfer process between Pr 3+ and Yb 3+ ions in the GCs compared to the as made glass. The highest value of energy transfer efficiency is 59% and the highest theoretical quantum efficiency is 159%, obtained for GCs 0.1-0.5 Pr-Yb treated at 620°C for 40 h.Keywords: transparent, glass-ceramics, rare-earths, crystallization, down-conversion, solar energy inTrODUcTiOn Solar green energy is one of the emerging fields where rare earth (RE) ions are intensively used to improve silicon solar cells (SSCs) efficiency. In fact, the most important routes to reduce costs and promote the use of solar energy are: decrease refining and crystallization cost of silicon (the most widely used semiconductor), to use less silicon (thinner cells), developing thin films solar cells of less expensive materials (organic, polymeric) and/or improving SSCs efficiency.Currently, many efforts are focused in the modification of the photovoltaic (PV) cells to make them more efficient. The main problem to improve PV energy conversion efficiency is associated with the spectral mismatch between the energy distribution of photons in the incident solar spectrum and the band-gap of silicon (Huang et al., 2013). Therefore, in the last years, solar down-converter materials doped with RE ions, able to convert the blue part of the solar spectrum to the range 980-1050 nm, where silicon presents the best response, are becoming increasingly important (Trupe et al., 2002;Richards, 2006;van der Ende et al., 2009). According to Abrams et al. (2011), a theoretical improvement of SSCs could be as high as 7% for an ideal lossless system; however, improvements (even though smaller than 7%) could be reached with a properly engineered solar converter layer.Among the converter materials, glasses and glass-ceramics (GCs) for PV application are increasingly important thanks to their relatively easy production and engineering and their capability of hosting a great variety of RE ions in different concentrati...

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Processing of transparent glass-ceramics by nanocrystallisation of LaF3

Cited by 48 publications

References 17 publications

Transparent oxyfluoride glass ceramics

Transparent oxyfluoride glass ceramics

Tuneable Nanostructuring of Highly Transparent Zinc Gallogermanate Glasses and Glass‐Ceramics

Transparent Oxyfluoride Nano-Glass Ceramics Doped with Pr3+ and Pr3+–Yb3+ for NIR Emission

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