Application of Nitride and Oxynitride Compounds to Various Phosphors for White LED

2008 ◽  
Vol 403 ◽  
pp. 15-18 ◽  
Author(s):  
Kyota Uheda
Keyword(s):  
Rare Earth ◽  
Thermal Quenching ◽  
Rare Earth Ions ◽  
White Led ◽  
Green Phosphor ◽  
Strong Emission ◽  
Red Phosphor ◽  
Blue Phosphor ◽  
Uv Led ◽  
Intense Emission

Multiternary nitride and oxynitride compounds doped with rare earth ions, such as Eu2+ and Ce3+ have been enthusiastically applied as various phosphors to white LED. New red and green phosphors, CaAlSiN3:Eu and Ba3Si6O12N2:Eu, have been successfully synthesized, recently. The red phosphor has intense emission around 650 nm under two different irradiations at 405 and 455 nm from blue- and near UV-LED chips, respectively; while strong emission is observed around 520 nm from the green phosphor. Both phosphors also show small thermal quenching over the temperatures up to 150 °C. In addition, both LaSi3N5:Ce and La3Si8O4N11:Ce in lanthanum silicon nitride and oxynitride were examined as candidates for a blue phosphor in white LED with near UV-LED chip.

scholarly journals Microstructural and optical properties of rare earth ions doped TiO2 for potential white LED applications

2018 ◽  
Vol 29 (19) ◽  
pp. 16824-16835 ◽  
Author(s):  
Mohamed Zikriya ◽  
Y. F. Nadaf ◽  
C. Manjunath ◽  
C. G. Renuka
Keyword(s):  
Optical Properties ◽  
Rare Earth ◽  
Rare Earth Ions ◽  
White Led ◽  
Doped Tio2

Rare earth ions doped full-color luminescence glasses for white LED

2007 ◽  
Vol 126 (2) ◽  
pp. 707-710 ◽  
Author(s):  
Chaofeng Zhu ◽  
Yunxia Yang ◽  
Xiaoluan Liang ◽  
Shuanglong Yuan ◽  
Guorong Chen
Keyword(s):  
Rare Earth ◽  
Rare Earth Ions ◽  
White Led ◽  
Full Color

New Green Phosphor Ba3Si6O12N2:Eu for White LED: Crystal Structure and Optical Properties

2008 ◽  
Vol 403 ◽  
pp. 11-14 ◽  
Author(s):  
Masayoshi Mikami ◽  
Satoshi Shimooka ◽  
Kyota Uheda ◽  
Hiroyuki Imura ◽  
Naoto Kijima
Keyword(s):  
Crystal Structure ◽  
Thermal Quenching ◽  
First Principles Calculation ◽  
White Led ◽  
Green Phosphor ◽  
Near Ultraviolet ◽  
Light Excitation ◽  
Led Backlight ◽  
Green Photoluminescence ◽  
High Color Purity

A new oxynitride, Ba3Si6O12N2, has been synthesized. The crystal structure has been successfully determined by close collaboration between experiment and first-principles calculation. This compound doped with Eu exhibits intense green photoluminescence with high color purity under near-ultraviolet to blue light excitation; in particular, it has much less thermal quenching than (Ba,Sr,Eu)2SiO4. Thus (Ba,Eu)3Si6O12N2 appears promising green phosphor for white LED backlight for display. The atomic/electronic structure is discussed in comparison with Ba3Si6O9N4, which could not become efficient phosphor by doping Eu due to strong thermal quenching at room temperature.

Optical and Color Properties of Green and Red Phosphor Mixtures Doped into Hybrid Sol-Gel Matrix to Generate White Light

2016 ◽  
Vol 1133 ◽  
pp. 419-423 ◽  
Author(s):  
Nurul Huda Yusoff ◽  
Wedianti Shualdi ◽  
Nik Mohd Azmi Nik Abdul Aziz ◽  
Wan Mohammed Nazrul Wan Jaafar
Keyword(s):  
White Light ◽  
Sol Gel ◽  
Color Temperature ◽  
Integrating Sphere ◽  
Green Phosphor ◽  
Red Phosphor ◽  
Color Properties ◽  
Uv Led ◽  
Heat Treated ◽  
Color Rendering

Eu (tta)3phen and Tb (4DBBA)3TPPO were synthesized as red and green phosphor for generating white light under the excitation of UV LED. The phosphor materials were doped into hybrid sol-gel (VTES:TEOS) matrix with different ratio of 1:8, 1:16, 1:25, 1:30, 1:40 and 1:50. The samples were fabricated as thick films by drop-casting and heat treated at 60°C overnight. Photoluminescence spectra were measured using spectrafluorometer system. Measurement of color properties such as color rendering index (CRI), color temperature and Commission Internationale de L’Eclairge coordinates were recorded by exciting the samples using a 380nm UV LED and focused the generated light into an integrating sphere. Based on the results, the mix ratio of 1:40 produce the nearest coordinate within the white color region with color temperature around 4100K to 4200K.

Energy-Back-Transfer Process in Rare-Earth Doped AlGaN

2005 ◽  
Vol 866 ◽  
Author(s):  
A. Wakahara ◽  
T. Fujiwara ◽  
H. Okada ◽  
A. Yoshida ◽  
T. Ohshima ◽  
...  
Keyword(s):  
Rare Earth ◽  
Temperature Dependence ◽  
Transfer Process ◽  
Decay Time ◽  
Thermal Quenching ◽  
Rare Earth Ions ◽  
Transfer Model ◽  
Time Resolved ◽  
Peak Energy ◽  
Back Transfer

AbstractTemperature dependence of time-resolved photoluminescence (PL) properties for rare-earth ions (REIs: Eu, Tb, and Er) implanted AlxGa1-xN (x=0∼1) is investigated. Thermal quenching for RE-related PL becomes small when increasing the Al contents. The PL decay time of REIs used in the present work becomes shorter when increasing the temperature and/or PL peak energy. The temperature dependence of PL intensity and the decay time are analysed by assuming phonon assisted energy-back-transfer model, in which the energy in REIs escape to trap levels. From the results, the improvement of PL properties can be well explained by the model, in which the activation energy for energy-back-transfer process is increased as increasing the Al contents.

Strong f ‐ f Excitation and Bright Red Emission in Cd 4 Gd 1‐ x Eu x O(BO 3 ) 3 (0≤ x ≤1): Near‐UV LED Pumped Red Phosphor with Low Thermal Quenching

2019 ◽  
Vol 14 (9) ◽  
pp. 1541-1548 ◽  
Author(s):  
Chao Yin ◽  
Mufei Yue ◽  
Pengfei Jiang ◽  
Ruirui Yang ◽  
Xianju Zhou ◽  
...  
Keyword(s):  
Thermal Quenching ◽  
Red Phosphor ◽  
Red Emission ◽  
Uv Led

Rare earth-free high color rendering white light-emitting diodes using CsVO3 with highest quantum efficiency for vanadate phosphors

2015 ◽  
Vol 3 (41) ◽  
pp. 10748-10754 ◽  
Author(s):  
Tomohiko Nakajima ◽  
Masahiko Isobe ◽  
Yuko Uzawa ◽  
Tetsuo Tsuchiya
Keyword(s):  
Rare Earth ◽  
Quantum Efficiency ◽  
Internal Quantum Efficiency ◽  
White Led ◽  
Red Phosphor ◽  
Light Emitting ◽  
Color Rendering Index ◽  
White Light Emitting Diodes ◽  
Color Rendering ◽  
Very High

Internal quantum efficiency of CsVO3 was considerably enhanced up to 95.8%, and a rare earth free white LED that had a very high color rendering index of 91.1 was realized by using CsVO3 and a deep red phosphor Mg2TiO4:Mn4+.

Multicolor up-conversion emission in tellurite glasses co-doped with rare earth ions for white LED applications

2014 ◽  
Author(s):  
Paweł Sienkiewicz ◽  
Anna Palkowska ◽  
Marcin Pietrzycki ◽  
Patryk Romanczuk ◽  
Jacek Zmojda ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Ions ◽  
Tellurite Glasses ◽  
White Led ◽  
Co Doped

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

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