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The formation mechanism of Cd–S–Se quantum dots (QDs) with a CdS/CdSe core–shell structure within a silicate glass system was investigated by monitoring the change in the first excitonic absorption peak of CdSe, CdS, and Cd–S–Se QDs as a function of the heat‐treatment (HT) duration. When a silicate glass containing QD formation components for CdSe or CdS single‐phased QDs was heat‐treated, CdSe QDs grew via Ostwald ripening, whereas CdS QDs hardly formed within the given silicate glass matrix. When the glass, including CdO, ZnSe, and ZnS, was utilized for the synthesis of Cd–S–Se QDs within the glass matrix, Cd–S–Se QDs were successfully formed and exhibited similar growth behavior to CdSe QDs during the initial stage of HT. The structural changes in the QD‐embedded glasses during HT were also monitored by Raman spectroscopy and discussed, and a possible formation mechanism of CdSe/CdS core–shell‐structured QDs within silicate glasses is suggested. [ABSTRACT FROM AUTHOR]

Nd3+-doped silicate glass (Nd-glass) was employed as a color filter for a white LED based on red and green phosphor (RG-LED), to manipulate the photoluminescence spectral shape and thus to provide a wider color gamut. The hypersensitive transition of Nd3+:4I9/2→4G5/2,2G7/2 was adjusted via glass composition and Nd concentration, and improved absorbance as well as reduced the absorption bandwidth. The effective absorption of the Nd-glass at ~580 nm reduced the spectral linewidth of the green and red emissions, improving the color reproduction range. The color gamut of the RG-LED was improved from 75.3% to 81.6% NTSC by the introduction of Nd-glass as a color filter. Reliability under high operating current and high temperature were also examined and discussed. [ABSTRACT FROM AUTHOR]

A complete inorganic quantum dot color converter for a white LED is achieved using silicate-based quantum-dot-embedded glasses (QDEGs). The white LED exhibits a high CRI of 90 and highly improved thermal stability up to 200 °C, demonstrating its robustness and practicality. The CdSe/CdS core/shell structure within the silicate glass is expected to enhance the colour converting efficiency. [ABSTRACT FROM AUTHOR]

Silicate glasses with CdS and CdSe quantum dots ( QDs) were synthesized for application as an inorganic color converter for a 450-nm blue light-emitting diode ( LED). CdO and ZnS (or ZnSe) were added, and heat treatment conditions were changed to control QD formation within the silicate matrix. Absorption spectra and high-resolution transmission electron microscopy confirmed the QD formation. Variations in absorption and photoluminescence ( PL) spectra were observed with CdSe QD-embedded glasses when heat treatment conditions varied, whereas glasses with CdS QDs did not show noticeable variation. QD-embedded glasses were then mounted on top of a 450-nm LED chip to make a color-converted LED, and their electroluminescence and PL spectra as well as CIE color coordinates were investigated. The practical potential of QD-embedded glasses as an inorganic color converter has been observed, and their spectral properties were discussed. [ABSTRACT FROM AUTHOR]

Silicate glasses containing CdS and Ag2O were made by the melt-quenching method. CdS quantum dots ( QDs) were precipitated inside the glass matrix by heat treatment at 570-590 °C for 10 h, and the influence of Ag on photoluminescence ( PL) of CdS QDs was investigated. The emission located at 478-493 nm in wavelength originated from the direct recombination of electron/hole pairs was quenched due to charger transfer between Ag and CdS QDs. Modification of PL from CdS QDs by Ag provides potentials toward developing the color changing materials for light-emitting diodes ( LEDs). [ABSTRACT FROM AUTHOR]

A phosphor-in-glass (PiG) was fabricated to realize a robust white light emitting diode (wLED) with wide color gamut. β-SiAlON:Eu2+ and CaAlSiN 3 :Eu2+ were employed for the green and red phosphors, respectively. Nd 2 O 3 doped silicate glass was used to reduce the emission bandwidths of the phosphors, utilizing the hypersensitive transition of Nd3+: 4I 9/2 → 4G 5/2 , 2G 7/2. The content of green and red phosphors was varied to produce a white emission. The emission spectra, color coordinates and color gamuts of the wLEDs with the PiGs were examined by varying phosphors and Nd 2 O 3 content. A wLED with 5 mol% Nd 2 O 3 doped glass had an enhanced color gamut up to 88%. The thermal stability of the PiGs was also monitored to demonstrate its practical feasibility as a white light source in display applications. • A white LED was realized with a PiG using β-SiAlON:Eu2+ and CASN:Eu2+. • The color gamut has been enhanced up to 88% by introducing Nd-doped silicate glass. • The PiG showed high thermal stability and its practical feasibility. [ABSTRACT FROM AUTHOR]

Various rare earth (RE) oxides such as Pr 2 O 3 , Dy 2 O 3 , Ho 2 O 3 , and Er 2 O 3 were introduced into Cd–S–Se quantum dot embedded glasses (QDEGs) to investigate their effect on the color conversion properties of the Cd–S–Se QDEGs. The absorption and emission peak wavelengths due to the excitonic transition of the Cd–S–Se QDs were modified by the introduction of RE oxides, implying their influence on QD formation. The photoluminescence of the various QDEGs RE oxides under 450 nm excitation were monitored and compared with the un-doped QDEGs. White LEDs (wLEDs) were also fabricated with the RE-doped QDEGs and their color conversion properties, such as quantum yield (QY), luminous efficacy, correlated color temperature (CCT) and color rendering index (CRI) were examined. Transmission electron microscope (TEM) revealed that the size and spatial distribution of the QDs were improved by the RE-oxides. Their effect on QD formation within the silicate glass was discussed using Raman spectroscopy. • Cd–S–Se quantum dot embedded glasses (QDEG) with various rare earth (RE) ions were fabricated. • RE ions reduced QD size and modified spectral properties of QDEGs. • RE ions improved size and spatial distribution of QDs within glass matrix. • White LED was successfully achieved with RE-doped QDEGs. [ABSTRACT FROM AUTHOR]

Silicate glasses based on SiO 2 –B 2 O 3 -BaO-WO 3 (SBBW) are synthesized with varying added Al 2 O 3 content, and their thermal and structural properties are examined as a sealing material for reversible solid oxide fuel cells (RSOCs). When up to 17.5 mol%, Al 2 O 3 is added, glass stability is improved at the expense of viscosity at sealing temperature. The glass transition temperature (T g), coefficient of thermal expansion (CTE) and flow at sealing temperature are investigated while varying Al 2 O 3 content, to find the proper composition for RSOC sealing. The structural changes in the glasses resulting from the Al 2 O 3 are inspected using Raman spectroscopy and an X-ray diffractometer. The adhesion characteristics of the glasses are examined by applying the glasses between NiO-yittria stabilized zirconia (NiO-YSZ) and Crofer22APU. A RSOC stack with 15 cells is prepared with glass containing 10 mol% of Al 2 O 3 as a sealing material, and the practical feasibility of the glass is successfully demonstrated. The open circuit voltage is monitored while cycling the RSOC stack between water electrolysis mode and fuel cell mode. [ABSTRACT FROM AUTHOR]

Phosphor-in-glasses (PiGs) with rare earth (RE) doped SiO 2 –B 2 O 3 –RO glasses were prepared by embedding YAG:Ce 3+ as the yellow phosphor. Eu 3+ and Pr 3+ were used to dope the glass, varying their concentrations in order to provide red emissions for possible chromaticity-control of white-light emitting diodes (WLEDs). The glass-to-phosphor mixing ratio was also varied to find the proper combination for color-controlled white LEDs. PiGs with RE-doped glasses were sintered at 750 °C and polished to 250 μm in thickness for blue LED color conversion. The photoluminescence spectra of the PiGs were monitored after they were mounted on commercial blue LED chips. Variation of color coordination, color rendering index and correlated color temperature were observed due to red emissions from the doped RE-ions. The spectral contribution of Eu 3+ and Pr 3+ ions to white LEDs under 450 nm LED excitation was discussed. The spatial distribution of phosphors within the glass matrix, and their possible interaction, was inspected by SEM. The thermal quenching effect was also investigated. [ABSTRACT FROM AUTHOR]

We demonstrate all-in-one-type organic light-emitting diodes (OLEDs) that are fabricated using a color converting plate as a substrate. The color converting plate is Pb-free phosphor-in-glass (PiG), which is prepared by mixing Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) and SiO 2 –B 2 O 3 –RO (R = Ba, Zn) glass frit by sintering at 750 °C for 30 min. The maximum luminance, luminance efficiency, and power efficiency of blue OLEDs fabricated on commercial glass are measured as 10500 cd/m 2 , 10.18 cd/A, and 2.95 lm/W, respectively. The Commission Internationale de l'Eclairge (CIE) coordinates of blue OLEDs is (0.167, 0.325). Our obtained results show that the luminance value decreased as the PiG thickness increased, and the glass to phosphor (GTP) ratio decreased. The OLED devices fabricated on the PiG substrate (GTP ratio = 9:1, thickness: 150 μm) showed a maximum luminance, luminance efficiency, and power efficiency of 7600 cd/m 2 , 8.76 cd/A, and 2.85 lm/W, respectively. The CIE color coordinates changed to (0.286, 0.504) at 200 mA/cm 2 . These results proved that color coordination can be easily adjusted by varying the GTP ratio and the thickness of the PiG. [ABSTRACT FROM AUTHOR]

Abstract: We experimentally verified, within silicate glasses, the formation of Se2 − color centers that are responsible for a broad visible emission under optical excitation at UV wavelengths. In addition to Raman spectra, all the spectroscopic analyses on absorption, photoluminescence, and photoluminescence excitation unanimously confirm the formation of Se2 − color centers. However, the visible absorption due to Se2 − color centers disppeared upon increasing concentration of Na2O, which implies that their formation would depend on the compositions of silicate glasses. The role of Na2O in the formation mechanism in relation to glass structure is then discussed in terms of various analyses on X-ray diffraction patterns, X-ray photoelectron spectroscopy, and Raman spectroscopy. [Copyright &y& Elsevier]

Abstract: Rare earth doped oxyfluoride glass ceramics with LaF3 nano-crystals formed inside were fabricated for color converter of UV-LED. Among various rare earth ions, Dy3+ and Eu3+ showed practically utilizable visible emissions under UV-LED excitation of 365nm. The visible emission has been improved by the formation of LaF3 brought by heat treatment. X-ray diffraction and transmission electron microscopy along with its energy dispersive spectra confirmed the formation of LaF3 nano-crystals. Compositional dependence and the effects of heat treatment conditions on the visible emissions have been investigated. The CIE chromaticity coordinates of the glasses were also examined for Dy3+ singly doped and co-doped samples. The effect of LaF3 nano-crystals and co-dopants on the visible emission properties of Dy3+ was discussed. [Copyright &y& Elsevier]

Abstract: We experimentally verify that a color center in the form of takes shape in silicate glasses containing relatively small amount of ZnSe which are prepared via a conventional melt-quenching process. Samples also produce broad photoluminescence when excited with UV light source, suggesting potential applications in the visible range. Analyses based on X-ray diffraction patterns, high resolution transmission electron microscopy, and Raman spectroscopy support the formation of color centers in addition to Se nanocrystals. [Copyright &y& Elsevier]