The temperature-dependent luminescence properties of BaAl2−xSixO4−xNx:Eu2+ and its application in yellowish-green light emitting diode

2009 ◽  
Vol 24 (8) ◽  
pp. 2589-2595 ◽  
Author(s):  
Mei Zhang ◽  
Baohong Li ◽  
Jing Wang ◽  
Zhiyang Zhang ◽  
Qiuhong Zhang ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Forward Bias ◽  
Green Light ◽  
Thermal Quenching ◽  
Energy Shift ◽  
Light Emitting ◽  
Yellowish Green ◽  
Near Ultraviolet ◽  
Increasing Temperature ◽  
Cation Sites

The influences of (SiN)+ and Eu2+ concentration on the optical properties of BaAl2−xSixO4−xNx:Eu2+ were investigated. The lifetime results show that there are two different cation sites occupied by Eu2+ ions and the energy transfer occurs between them. The Huang–Rhys factor and the Stokes energy shift were determined, and thermal quenching with increasing temperature was observed. Finally, intense yellowish-green light emitting diodes (LED) with the color coordinate of (0.2936, 0.4483) under a forward-bias current of 20 mA was successfully fabricated on the basis of a structure consisting of BaAl2−xSixO4−xNx:Eu2+ phosphor and near-ultraviolet (∼395 nm) GaN chip.

Phosphor-Conversion White Light Emitting Diode Using InGaN Near-Ultraviolet Chip

2007 ◽  
Vol 124-126 ◽  
pp. 499-502 ◽  
Author(s):  
Kyoung Jae Choi ◽  
Joung Kyu Park ◽  
Kyung Nam Kim ◽  
Chang Hae Kim ◽  
Ho Kun Kim
Keyword(s):  
White Light ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Forward Bias ◽  
Color Temperature ◽  
Operating Voltage ◽  
Current Increase ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Yellow Region

We have synthesized a Eu2+-activated Sr3MgSi2O8 blue phosphor and (Sr,Ba)2SiO4 yellow phosphor. We fabricated a phosphor-conversion white light emitting diode(LED) using an InGaN chip that emits 400 nm near-ultraviolet(n-UV) light and phosphors that emit in the blue and yellow region. When the white LED was operated at a forward-bias current of 20 mA at room temperature(RT), the color temperature(Tcp), average color rendering(Ra), operating voltage(Vf) and luminous efficacy(ηL) were estimated to be 5800K, 72.08, 3.4V, and 7.61 lm/W, respectively. The commission International de I’Eclarirage(CIE) chromaticity coordinates obtained from the measured spectra remained almost constant during the forward-baias current increase from 0.5 mA to 60 mA.

n-type GaN surface etched green light-emitting diode to reduce non-radiative recombination centers

2021 ◽  
Vol 118 (2) ◽  
pp. 021102
Author(s):  
Dong-Pyo Han ◽  
Ryoto Fujiki ◽  
Ryo Takahashi ◽  
Yusuke Ueshima ◽  
Shintaro Ueda ◽  
...  
Keyword(s):  
Radiative Recombination ◽  
Light Emitting Diode ◽  
Green Light ◽  
Light Emitting ◽  
Recombination Centers

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.

scholarly journals Electroluminescence and photo-response of inorganic halide perovskite bi-functional diodes

Nanophotonics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 1981-1988 ◽  
Author(s):  
Ning Li ◽  
Ying Suet Lau ◽  
Yanqin Miao ◽  
Furong Zhu
Keyword(s):  
Visible Light ◽  
High Speed ◽  
Light Emission ◽  
Forward Bias ◽  
Green Light ◽  
Visible Light Communication ◽  
Light Emitting ◽  
Response Characteristics ◽  
Photo Response ◽  
Halide Perovskite

AbstractIn this work, we report our efforts to develop a novel inorganic halide perovskite-based bi-functional light-emitting and photo-detecting diode. The bi-functional diode is capable of emitting a uniform green light, with a peak wavelength of 520 nm, at a forward bias of >2 V, achieving a high luminance of >103 cd/m2 at 7 V. It becomes an efficient photodetector when the bi-functional diode is operated at a reverse bias, exhibiting sensitivity over a broadband wavelength range from ultraviolet to visible light. The bi-functional diode possesses very fast transient electroluminescence (EL) and photo-response characteristics, e.g. with a short EL rising time of ~6 μS and a photo-response time of ~150 μS. In addition, the bi-functional diode also is sensitive to 520 nm, the wavelength of its peak EL emission. The ability of the bi-functional diodes for application in high speed visible light communication was analyzed and demonstrated using two identical bi-functional diodes, one performed as the signal generator and the other acted as a signal receiver. The dual functions of light emission and light detection capability, enabled by bi-functional diodes, are very attractive for different applications in under water communication and visible light telecommunications.

Green Light Emitting Diode Irradiation Enhances Fibroblast Growth Impaired by High Glucose Level

2005 ◽  
Vol 23 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Elke M. Vinck ◽  
Barbara J. Cagnie ◽  
Maria J. Cornelissen ◽  
Heidi A. Declercq ◽  
Dirk C. Cambier
Keyword(s):  
Glucose Level ◽  
High Glucose ◽  
Light Emitting Diode ◽  
Green Light ◽  
Fibroblast Growth ◽  
Light Emitting ◽  
High Glucose Level

scholarly journals AlGaN-InGaN-GaN Near Ultraviolet Light Emitting Diode

2008 ◽  
Vol 45 (4) ◽  
pp. 25-32 ◽  
Author(s):  
L. Dimitrocenko ◽  
J. Grube ◽  
P. Kulis ◽  
G. Marcins ◽  
B. Polyakov ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Electron Tunneling ◽  
Light Emitting Diode ◽  
Vapour Phase ◽  
Single Quantum Well ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Near Ultraviolet ◽  
Metal Organic ◽  
Organic Vapour

AlGaN-InGaN-GaN Near Ultraviolet Light Emitting DiodeA 382-nm InGaN/AlGaN light-emitting diode (LED) was made on a sapphire substrate by metal-organic vapour phase deposition (MOCVD) technique. Growing of the undoped and Si-doped GaN and AlxGa1-xN monocrystalline layers with a surface roughness of < 1 nm required for making light emitting devices has been carried out. To enhance the LED emission efficiency, a modified symmetric composition of an active single quantum well (SQW) structure was proposed. In addition to the conventional p-doped AlGaN:Mg electron overflow blocking barrier, ann-doped AlGaN:Si SQW barrier layer in the structure was formed that was meant to act as an additional electron tunneling barrier.

Promotion of neural sprouting using low-level green light-emitting diode phototherapy

2015 ◽  
Vol 20 (2) ◽  
pp. 020502 ◽  
Author(s):  
Noa Alon ◽  
Hamootal Duadi ◽  
Ortal Cohen ◽  
Tamar Samet ◽  
Neta Zilony ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Green Light ◽  
Light Emitting ◽  
Low Level

scholarly journals A 3 W High-Voltage Single-Chip Green Light-Emitting Diode with Multiple-Cells Network

2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
W. Wang ◽  
Y. Cai ◽  
Y. B. Zhang ◽  
H. J. Huang ◽  
W. Huang ◽  
...  
Keyword(s):  
High Voltage ◽  
Light Emitting Diode ◽  
Light Output ◽  
Green Light ◽  
Current Crowding ◽  
Single Chip ◽  
Light Output Power ◽  
Large Area ◽  
Light Emitting ◽  
Multiple Cells

A parallel and series network structure was introduced into the design of the high-voltage single-chip (HV-SC) light-emitting diode to inhibit the effect of current crowding and to improve the yield. Using such a design, a6.6×5 mm2large area LED chip of 24 parallel stages was demonstrated with 3 W light output power (LOP) at the current of 500 mA. The forward voltage was measured to be 83 V with the same current injection, corresponding to 3.5 V for a single stage. The LED chip’s average thermal resistance was identified to be 0.28 K/W by using infrared thermography analysis.

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