scholarly journals A Novel Red-Emitting Na2NbOF5:Mn4+ Phosphor with Ultrahigh Color Purity for Warm White Lighting and Wide-Gamut Backlight Displays

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5317
Author(s):  
Jingshan Hou ◽  
Wenxiang Yin ◽  
Langping Dong ◽  
Yang Li ◽  
Yufeng Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Red Light ◽  
Luminescent Properties ◽  
Fluorescence Decay ◽  
Color Temperature ◽  
Color Purity ◽  
Zero Phonon Line ◽  
Light Emitting

In this work, a novel red-emitting oxyfluoride phosphor Na2NbOF5:Mn4+ with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of Na2NbOF5:Mn4+ were studied in detail. The photoluminescence excitation spectrum contains two intense excitation bands centered at 369 and 470 nm, which match well with commercial UV and blue light-emitting diode (LED) chips. When excited by 470 nm blue light, Na2NbOF5:Mn4+ exhibits red light emission dominated by ZPL. Notably, the color purity of the Na2NbOF5:Mn4+ red phosphor can reach 99.9%. Meanwhile, the Na2NbOF5:Mn4+ phosphor has a shorter fluorescence decay time than commercial K2SiF6:Mn4+, which is conducive to fast switching of images in display applications. Profiting from the intense ZPL, white light-emitting diode (WLED) with high color rendering index of Ra = 86.2 and low correlated color temperature of Tc = 3133 K is realized using yellow YAG:Ce3+ and red Na2NbOF5:Mn4+ phosphor. The WLED fabricated using CsPbBr3 quantum dots (QDs) and red Na2NbOF5:Mn4+ phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting Na2NbOF5:Mn4+ phosphor has potential application prospects in WLED lighting and display backlight.

Tunable luminescence from Sm3+, Ce3+ codoped Al2O3–La2O3–SiO2 glasses for white light emission

2009 ◽  
Vol 24 (5) ◽  
pp. 1730-1734 ◽  
Author(s):  
Hucheng Yang ◽  
G. Lakshminarayana ◽  
Yu Teng ◽  
Shifeng Zhou ◽  
Jianrong Qiu
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Spectral Properties ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Fluorescence Decay ◽  
White Light Emission ◽  
Luminescence Properties ◽  
Light Emitting ◽  
Luminescence Efficiency

Sm3+, Ce3+ codoped Al2O3–La2O3–SiO2 glasses were prepared and their luminescence properties were characterized. Blue-cyan to orange-red tunable luminescence was observed from these glasses with different excitation wavelengths ranging from 385 to 410 nm. White light emission with internal luminescence efficiency 42% has been observed using commercially available purple light-emitting-diode excitation. The energy transfer between Ce3+ and Sm3+ has also been investigated from fluorescence decay curves and spectral properties.

scholarly journals High Efficiency and Color Rendering Quantum Dots White Light Emitting Diodes Optimized by Luminescent Microspheres Incorporating

Nanophotonics ◽  
2016 ◽  
Vol 5 (4) ◽  
pp. 565-572 ◽  
Author(s):  
Wei Chen ◽  
Kai Wang ◽  
Junjie Hao ◽  
Dan Wu ◽  
Jing Qin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
High Efficiency ◽  
Lattice Structure ◽  
Light Emitting Diode ◽  
Luminescent Properties ◽  
Color Temperature ◽  
High Quantum Efficiency ◽  
Light Emitting ◽  
Color Rendering

AbstractIn this research, we have developed an approach by incorporating quantum dots (QDs) with red emission into mesoporous silica microspheres through a non-chemical process and obtained luminescent microspheres (LMS). Owing to the lattice structure of LMS, QDs were effectively protected from intrinsic aggregation in matrix and surface deterioration by encapsulant, oxygen and moisture. The LMS composite has therefore maintained large extent luminescent properties of QDs, espe-cially for the high quantum efficiency. Moreover, the fabricated white light emitting diode (WLED) utilizing LMS and YAG:Ce yellow phosphor has demonstrated excellent light performance with color coordinates around (x = 0.33, y = 0.33), correlated color temperature between 5100 and 5500 K and color rendering index of Ra = 90, R9 = 95. The luminous efficiency of the WLED has reached up to a new record of 142.5 lm/W at 20 mA. LMS provide a promising way to practically apply QDs in lightings and displays with high efficiency as well as high stability.

Enhanced Red-Light Emission by Local Plasmon Coupling of Au Nanorods in an Organic Light-Emitting Diode

2011 ◽  
Vol 4 (3) ◽  
pp. 032105 ◽  
Author(s):  
Takuya Tanaka ◽  
Yuji Totoki ◽  
Aya Fujiki ◽  
Nobuyuki Zettsu ◽  
Yusuke Miyake ◽  
...  
Keyword(s):  
Light Emission ◽  
Light Emitting Diode ◽  
Red Light ◽  
Plasmon Coupling ◽  
Light Emitting ◽  
Au Nanorods ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Local Plasmon

Design, Synthesis and Charaterization of Polymers Derived from Fluorene for Application in RGB Polymer Light-Emitting-Diodes

2001 ◽  
Vol 665 ◽  
Author(s):  
Serge Beaupré ◽  
Mario Leclerc ◽  
Isabelle Lévesque ◽  
Marie D'Iorio
Keyword(s):  
Solid State ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Red Light ◽  
Synthetic Approach ◽  
Cyclic Voltammogram ◽  
New Approach ◽  
Light Emitting ◽  
Polymer Light Emitting Diode ◽  
Polyfluorene Derivatives

ABSTRACTIn order to obtain efficient blue, green and red light-emitters as active layers in polymer light-emitting diode (PLEDs), we report herein the design, the synthesis, and the characterization of new polyesters and copolymers derived from fluorene. We will focus on a new approach to obtain a stable, high luminance blue emitter via polyesters derived from fluorene. The versatile synthetic approach allows the easy design of a whole class of new and tunable electroactive and photoactive aromatic polyesters. Poly(1,6-hexane- 9,9′,9′,9′′,9′′-hexahexyl-7,2′;7′,2′′-terfluorene-2,7′′-dicarboxylate) (PTFHHC6) and Poly(1,6-hexane-2,7-Bis(1,1′-biphenylen-4-yl-4′-dicarboxylate)-9,9-dioctylfluorene) (PE-BP-DOF-BP) exhibit strong emission in the blue range, both in solution and in the solid state. Moreover, these polyesters present some advantages over other polyfluorene derivatives. For example, their solid-state fluorescence spectrum does not show the formation of any excimer and does not vary upon thermal treatment. We will also present copolymers derived from fluorene which emit green light and a new approach to obtain red polymer light-emitting-diode will also be shown. Optical properties such as light absorption, light emission and quantum yield of fluorescence in solution as well as electrical properties such as cyclic voltammogram and conductivity in-situ are reported. Finally, some of the polymers presented have been tested in PLEDs devices and the preliminary results seem promising for the development of multicoloured displays made from the same class of polyfluorene derivatives.

scholarly journals Sr2−xBaxTiO4:Eu3+, Gd3+: A Novel Blue Converting Yellow-Emitting Phosphor for White Light-Emitting Diodes

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Limin Dong ◽  
Jiatong Zhao ◽  
Qin Li ◽  
Zhidong Han
Keyword(s):  
Blue Light ◽  
White Light ◽  
Single Phase ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Excitation Wavelength ◽  
Light Emitting ◽  
Gel Method ◽  
White Light Emitting Diodes

A highly intense yellow-emitting phosphorSr2-xBaxTiO4:Eu3+,Gd3+peaking at 593–611 nm was synthesized by the sol-gel method. XRD and SEM show that the samples are single phase and have irregular shape. The excitation wavelength matches well with that of the emission of the blue-light-emitting diode. The emission peaks at 593 and 611 nm are attributed to the transitions from the5D0-7F1and5D0-7F2ofEu3+ions, respectively.Gd3+was used as sensitizer, aiming at increasing the luminous intensity. A certain amount ofSr2+andBa2+is contributed to the intensity of light emission.

Dynamic Color Temperature White Lighting Source Based on Red Green and Blue Light Emitting Diode

2011 ◽  
Vol 31 (5) ◽  
pp. 0523004 ◽  
Author(s):  
殷录桥 Yin Luqiao ◽  
杨卫桥 Yang Weiqiao ◽  
李抒智 Li Shuzhi ◽  
程备 Cheng Bei ◽  
张建华 Zhang Jianhua
Keyword(s):  
Blue Light ◽  
Light Emitting Diode ◽  
Color Temperature ◽  
Light Emitting

scholarly journals Blue Light-emitting Diode Light Irradiation of Seedlings Improves Seedling Quality and Growth after Transplanting in Red Leaf Lettuce

HortScience ◽  
2010 ◽  
Vol 45 (12) ◽  
pp. 1809-1814 ◽  
Author(s):  
Masahumi Johkan ◽  
Kazuhiro Shoji ◽  
Fumiyuki Goto ◽  
Shin-nosuke Hashida ◽  
Toshihiro Yoshihara
Keyword(s):  
Leaf Area ◽  
Blue Light ◽  
Antioxidant Activities ◽  
Light Emitting Diode ◽  
Red Light ◽  
Seedling Quality ◽  
Carotenoid Content ◽  
Light Emitting ◽  
Leaf Lettuce ◽  
Led Lights

In this study, we determined the effects of raising seedlings with different light spectra such as with blue, red, and blue + red light-emitting diode (LED) lights on seedling quality and yield of red leaf lettuce plants. The light treatments we used were applied for a period of 1 week and consisted of 100 μmol·m−2·s−1 of blue light, simultaneous irradiation with 50 μmol·m−2·s−1 of blue light and 50 μmol·m−2·s−1 of red light, and 100 μmol·m−2·s−1 of red light. At the end of the light treatment, that is 17 days after sowing (DAS), the leaf area and shoot fresh weight (FW) of the lettuce seedlings treated with red light increased by 33% and 25%, respectively, and the dry weight of the shoots and roots of the lettuce seedlings treated with blue-containing LED lights increased by greater than 29% and greater than 83% compared with seedlings grown under a white fluorescent lamp (FL). The shoot/root ratio and specific leaf area of plants irradiated with blue-containing LED lights decreased. At 45 DAS, higher leaf areas and FWs were obtained in lettuce plants treated with blue-containing LED lights. The total chlorophyll (Chl) contents in lettuce plants treated with blue-containing and red lights were less than that of lettuce plants treated with FL, but the Chl a/b ratio and carotenoid content increased under blue-containing LED lights. Polyphenol contents and the total antioxidant status (TAS) were greater in lettuce seedlings treated with blue-containing LED lights than in those treated with FL at 17 DAS. The higher polyphenol contents and TAS in lettuce seedlings at 17 DAS decreased in lettuce plants at 45 DAS. In conclusion, our results indicate that raising seedlings treated with blue light promoted the growth of lettuce plants after transplanting. This is likely because of high shoot and root biomasses, a high content of photosynthetic pigments, and high antioxidant activities in the lettuce seedlings before transplanting. The compact morphology of lettuce seedlings treated with blue LED light would be also useful for transplanting.

Oxygen vacancy-induced red light emission from flexible inorganic micropatterned p-CuO/n-ZnO heterojunction light-emitting diode

2016 ◽  
Vol 109 (17) ◽  
pp. 171102 ◽  
Author(s):  
Pranab Biswas ◽  
Sung-Doo Baek ◽  
Sang Hoon Lee ◽  
Jong-Woo Kim ◽  
Ji-Hyeon Park ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Red Light ◽  
Light Emitting

scholarly journals A Flexible Blue Light-Emitting Diode Based on ZnO Nanowire/Polyaniline Heterojunctions

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Y. Y. Liu ◽  
X. Y. Wang ◽  
Y. Cao ◽  
X. D. Chen ◽  
S. F. Xie ◽  
...  
Keyword(s):  
Blue Light ◽  
Indium Tin Oxide ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Novel Device ◽  
Vertically Aligned ◽  
Doped Polyaniline ◽  
P Type

An organic/inorganic light-emitting diode (LED) consisting of n-type vertically aligned ZnO nanowires (NWs) and p-type proton acid doped polyaniline (PANi) is reported. The device was fabricated on flexible indium-tin-oxide (ITO) coated polyethylene terephthalate (PET) substrate. A broad blue light emission band ranging from 390 nm to 450 nm was observed in the electroluminescence (EL) spectra of the device, which was related to the interface recombination of electrons in the conduction band of ZnO NWs and holes in the polaron level of PANi. The turn-on voltage of the device is~3.5 V, lower than most of ZnO NWs based LED devices. In combination with the easy fabrication, flexibility, low power consumption, and mechanical robustness, this novel device is very promising in the application of blue LEDs.

scholarly journals Study of the Effect of Injection Currents on White Light Emission of Ce-Doped YAG Phosphor Powder Prepared by Microwave Combustion

2020 ◽  
Vol 301 ◽  
pp. 60-68 ◽  
Author(s):  
Husnen R. Abd ◽  
Zainuriah Hassan ◽  
Naser Mahmoud Ahmed ◽  
A.F. Omar ◽  
Khai Shenn Lau ◽  
...  
Keyword(s):  
White Light ◽  
Yttrium Aluminum Garnet ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Spherical Particles ◽  
Color Temperature ◽  
Phosphor Powder ◽  
Light Emitting ◽  
Microwave Combustion ◽  
Whole Process

The behaviors of yttrium aluminum garnet (YAG) phosphor powder doped by cerium (YAG:Ce3+) was studied. Here, the YAG:Ce3+ nanopowders have been synthesized using microwave combustion (MW) according to the formula, Y(3-0.04) Al5O12: 0.04Ce3+ to produce white light emitting diode (WLEDs) by conversion from blue indium gallium nitride light emitting diode (InGaN LED, 445 nm) chips; the whole process took only 20 min. Pure YAG phase was obtained after annealing at 1050 °C for 5 h with nonaggregated and spherical particles. Thermogravimetry and derivative thermogravimetry (TG/DTG), X-ray powder diffraction (XRPD), transmission electron microscope (TEM), photoluminescence (PL), electroluminescence (EL) emissions and standard CIE 1931 chromaticity diagrams have been used to characterize the samples. The highest WLEDs emission was achieved for the annealed YAG:Ce3+, together with proper color rendering index (CRI), and tunable correlated color temperature (CCT). Finally, we conclude that the decreasing EL intensity at increased injection current is caused by the thermal ionization from the 5d1 level to the conduction band.

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