scholarly journals Synthesis and Luminescence Properties of a Novel Green-Yellow-Emitting Phosphor BiOCl:Pr3+ for Blue-Light-Based w-LEDs

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1296 ◽  
Author(s):  
Qi Wang ◽  
Meiling Xie ◽  
Minghao Fang ◽  
Xiaowen Wu ◽  
Yan’gai Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
High Performance ◽  
Doping Concentration ◽  
Thermal Quenching ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Exchange Effect ◽  
Light Emitting ◽  
Good Thermal Stability ◽  
Luminescence Efficiency

The development of white-light-emitting diodes (w-LEDs) makes it meaningful to develop novel high-performance phosphors excited by blue light. Herein, BiOCl:Pr3+ green-yellow phosphors were prepared via a high-temperature solid-state reaction method. The crystal structure, luminescent properties, lifetime, thermal quenching behavior, and quantum yield were studied in detail. The BiOCl:Pr3+ phosphors presented several emission peaks located in green and red regions, under excitation at 453 nm. The CIE coordinates could be tuned along with the changed doping concentration with fair luminescence efficiency. The results also indicated that the optimized doping concentration of Pr3+ ions was at x = 0.0075 because of the concentration quenching behavior resulting from an intense exchange effect. When the temperature reached 150 °C, the intensity of the emission peak at 495 nm could remain at 78% of that at room temperature. The activation energy of 0.20 eV also confirmed that the BiOCl:Pr3+ phosphor exhibited good thermal stability. All these results indicate that the prepared products have potential to be used as a high-performance green-yellow-light-emitting phosphor for blue-light-based w-LEDs.

scholarly journals Blue-Light-Based White-LEDs based on a Novel Green-Yellow-Emitting Phosphor: Synthesis and Luminescence Properties

2019 ◽  
Author(s):  
Qi Wang ◽  
Meiling Xie ◽  
Minghao Fang ◽  
Xiaowen Wu
Keyword(s):  
Blue Light ◽  
High Performance ◽  
Doping Concentration ◽  
Thermal Quenching ◽  
Luminescent Properties ◽  
Exchange Effect ◽  
Light Emitting ◽  
White Leds ◽  
Good Thermal Stability ◽  
Luminescence Efficiency

The development of white-light-emitting diodes (w-LEDs) makes it meaningful to develop novel high-performance phosphors excited by blue light. Herein, BiOCl:Pr3+ green-yellow phosphors were prepared via a high-temperature solid-state reaction method. The crystal structure, luminescent properties, lifetime, thermal quenching behavior, and quantum yield were studied in detail. The BiOCl:Pr3+ phosphors presented several emission peaks located in green and red regions, under excitation at 453 nm. The CIE coordinates could be tuned along with the changed doping concentration with fair luminescence efficiency. The results also indicated that the optimized doping concentration of Pr3+ ions was at x = 0.0075 because of the concentration quenching behavior resulting from an intense exchange effect. When the temperature reached 150 °C, the intensity of the emission peak at 495 nm could remain at 78% of that at room temperature. The activation energy of 0.20 eV also confirmed that the BiOCl:Pr3+ phosphor exhibited good thermal stability. All these results indicate that the prepared products have potential to be used as a high-performance green-yellow-light-emitting phosphor for blue-light-based w-LEDs.

(K0.5Na0.5)NbO3:Eu3+/Bi3+: a novel, highly efficient, red light-emitting material with superior water resistance behavior

RSC Advances ◽  
2015 ◽  
Vol 5 (6) ◽  
pp. 4707-4715 ◽  
Author(s):  
Qiwei Zhang ◽  
Haiqin Sun ◽  
Tao Kuang ◽  
Ruiguang Xing ◽  
Xihong Hao
Keyword(s):  
Blue Light ◽  
White Light ◽  
High Performance ◽  
Water Resistance ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Light Emitting ◽  
Highly Efficient ◽  
White Light Emitting Diodes

Materials emitting red light (∼611 nm) under excitation with blue light (440–470 nm) are highly desired for fabricating high-performance white light-emitting diodes (LEDs).

scholarly journals Operando direct observation of spin-states and charge-trappings of blue light-emitting-diode materials in thin-film devices

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fumiya Osawa ◽  
Kazuhiro Marumoto
Keyword(s):  
Blue Light ◽  
High Performance ◽  
Density Functional ◽  
Light Emitting Diode ◽  
Green Light ◽  
Spin States ◽  
Light Emitting ◽  
Full Color ◽  
Color Displays ◽  
Materials Used

Abstract Spin-states and charge-trappings in blue organic light-emitting diodes (OLEDs) are important issues for developing high-device-performance application such as full-color displays and white illumination. However, they have not yet been completely clarified because of the lack of a study from a microscopic viewpoint. Here, we report operando electron spin resonance (ESR) spectroscopy to investigate the spin-states and charge-trappings in organic semiconductor materials used for blue OLEDs such as a blue light-emitting material 1-bis(2-naphthyl)anthracene (ADN) using metal–insulator–semiconductor (MIS) diodes, hole or electron only devices, and blue OLEDs from the microscopic viewpoint. We have clarified spin-states of electrically accumulated holes and electrons and their charge-trappings in the MIS diodes at the molecular level by directly observing their electrically-induced ESR signals; the spin-states are well reproduced by density functional theory. In contrast to a green light-emitting material, the ADN radical anions largely accumulate in the film, which will cause the large degradation of the molecule and devices. The result will give deeper understanding of blue OLEDs and be useful for developing high-performance and durable devices.

Highly efficient single-layer blue polymer light-emitting diodes based on hole-transporting group substituted poly(fluorene-co-dibenzothiophene-S,S-dioxide)

2017 ◽  
Vol 5 (37) ◽  
pp. 9680-9686 ◽  
Author(s):  
Feng Peng ◽  
Na Li ◽  
Lei Ying ◽  
Wenkai Zhong ◽  
Ting Guo ◽  
...  
Keyword(s):  
Blue Light ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Single Layer ◽  
Random Copolymer ◽  
Hole Transport ◽  
Light Emitting ◽  
Hole Transporting ◽  
Polymer Light Emitting Diodes ◽  
Copolymer Poly

We developed a series of high-performance blue light-emitting polymers that contain hole-transport moieties comprising carbazole or triphenylamine substituents in the side chains of random copolymer poly(fluorene-co-dibenzothiophene-S,S-dioxide) (PFSO).

Synthesis and Luminescent Properties of Strong Blue Light-Emitting Al[sub 2]O[sub 3]/ZnO Nanocables

2008 ◽  
Vol 155 (5) ◽  
pp. K96 ◽  
Author(s):  
Chi-Sheng Hsiao ◽  
Wan-Lin Kuo ◽  
San-Yuan Chen ◽  
Ji-Lin Shen ◽  
Chin-Ching Lin ◽  
...  
Keyword(s):  
Blue Light ◽  
Luminescent Properties ◽  
Light Emitting

Effect of Trace Fe3+ on Luminescent Properties of CaWO4: Pr3+ Phosphors

2016 ◽  
Vol 71 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Ke Wang ◽  
Xu Feng ◽  
Wenlin Feng ◽  
Shasha Shi ◽  
Yao Li ◽  
...  
Keyword(s):  
Doping Concentration ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Transfers ◽  
Decay Times ◽  
Lifetime Testing ◽  
Testing Techniques ◽  
The Mean

AbstractFe3+ undoped and doped CaWO4: Pr3+ phosphors have been successfully synthesised by using the solid-state reaction method. The products were characterised by powder X-ray diffraction (XRD), photoluminescence (PL) and fluorescence lifetime testing techniques, respectively. The mean crystallite size (50.7 nm) of CaWO4: Pr3+ is obtained from powder XRD data. PL spectra of both Fe3+ undoped and doped CaWO4: Pr3+ phosphors exhibit excitation peaks at 214, 449, 474, and 487 nm under monitor wavelength at 651 nm, and emission peaks at 532, 558, 605, 621, 651, 691, 712, and 736 nm under blue light (λem=487 nm) excitation. The effect of trace Fe3+ on luminescence properties of CaWO4: Pr3+ phosphor is studied by controlling the doping concentration of Fe3+. The results show that radioactive energy transfers from luminescence centre Pr3+ to quenching centre Fe3+ occurred in Fe3+ doped CaWO4: Pr3+ phosphors. With the increasing concentration of Fe3+, the energy transfer from Pr3+ to Fe3+ is enhanced, and the emission intensity of CaWO4: Pr3+ will be lower. The decay times (5.22 and 4.99 μs) are obtained for typical samples Ca0.995WO4: Pr3+0.005 and Ca0.99275WO4: Pr3+0.005, Fe3+0.00225, respectively. This work shows that nonferrous phosphors can improve the luminescent intensity of the phosphors.

Synthesis and luminescence properties of new red phosphor YBiW2O9:Eu3+

2017 ◽  
Vol 10 (05) ◽  
pp. 1750066 ◽  
Author(s):  
Zhi Xie ◽  
Wang Zhao ◽  
Wei-Wei Zhou ◽  
Fu-Gui Yang
Keyword(s):  
Internal Quantum Efficiency ◽  
Solid State Reaction Method ◽  
Potential Candidate ◽  
Red Phosphor ◽  
Light Emitting ◽  
Good Thermal Stability ◽  
Near Ultraviolet ◽  
Chromaticity Coordinate ◽  
White Light Emitting Diodes ◽  
First Time

A new series of YBiW2O9:Eu[Formula: see text] phosphors were successfully synthesized by the solid-state reaction method for the first time. Pure phase formation of YBiW2O9:Eu[Formula: see text] was confirmed by X-ray powder diffraction. It is found that the 7F[Formula: see text]L6 transition results in the strongest near-ultraviolet excitation centered at 395 nm and the phosphors show strong electric-dipole (ED) transitions (5D[Formula: see text]F[Formula: see text] with red emission peaking at 616[Formula: see text]nm. The optimal Eu[Formula: see text] doping concentration of 70[Formula: see text]mol.% is presented in YBiW2O9:Eu[Formula: see text] phosphors. The Y[Formula: see text]BiW2O9:0.7Eu[Formula: see text] phosphor has better Commission Internationale de l’Eclairage chromaticity coordinate of (0.669, 0.328) in comparison with commercial red-emitting phosphors (Y2O2S:Eu[Formula: see text], Y2O3:Eu[Formula: see text]. The internal quantum efficiency of Y[Formula: see text]BiW2O9:0.7Eu[Formula: see text] was measured to be 45.1%, and temperature-dependent luminescence shows its good thermal stability. All the results suggest that YBiW2O9:Eu[Formula: see text] is a potential candidate of red phosphor for the applications in white light emitting diodes.

scholarly journals Dependence of efficiencies in GaN-based vertical blue light-emitting diodes on the thickness and doping concentration of the n-GaN layer

2013 ◽  
Vol 21 (S1) ◽  
pp. A190 ◽  
Author(s):  
Han-Youl Ryu ◽  
Ki-Seong Jeon ◽  
Min-Goo Kang ◽  
Yunho Choi ◽  
Jeong-Soo Lee
Keyword(s):  
Blue Light ◽  
Doping Concentration ◽  
Light Emitting Diodes ◽  
Light Emitting
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