scholarly journals Fabrication of GaN-Based White Light-Emitting Diodes on Yttrium Aluminum Garnet-Polydimethylsiloxane Flexible Substrates

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Lung-Chien Chen ◽  
Wen-Wei Lin ◽  
Jun-Wei Chen
Keyword(s):  
Thin Film ◽  
White Light ◽  
Yttrium Aluminum Garnet ◽  
Light Emitting Diode ◽  
Flexible Substrates ◽  
Light Emitting ◽  
White Leds ◽  
Yttrium Aluminum ◽  
Lift Off ◽  
White Light Emitting Diodes

This study concerns the characteristics of white GaN-based light-emitting diode (LED) on flexible substrates. The thin film GaN-based blue LEDs were directly transferred from sapphire onto the flexible polydimethylsiloxane (PDMS) substrates by laser lift-off (LLO) process. The PDMS substrates were incorporated 10–40% cerium doped yttrium aluminum garnet phosphor, YAG:Ce3+, and formed the GaN-based white LEDs. The white LEDs prepared by the GaN-based LEDs on the YAG-PDMS substrates reveal one peak at 470 nm corresponding to the emission of the GaN-based LED and a broadband included five weak peaks caused by YAG:Ce3+phosphors.

Effects of electron-withdrawing groups in imidazole-phenanthroline ligands and their influence on the photophysical properties of EuIII complexes for white light-emitting diodes

2017 ◽  
Vol 41 (18) ◽  
pp. 9826-9839 ◽  
Author(s):  
Boddula Rajamouli ◽  
Rachna Devi ◽  
Abhijeet Mohanty ◽  
Venkata Krishnan ◽  
Sivakumar Vaidyanathan
Keyword(s):  
Thin Film ◽  
Quantum Yield ◽  
White Light ◽  
Light Emitting Diode ◽  
Photophysical Properties ◽  
Red Light ◽  
Europium Complexes ◽  
Light Emitting ◽  
White Light Emitting Diodes ◽  
Phenanthroline Ligands

The red light emitting diode (LED) was fabricated by using europium complexes with InGaN LED (395 nm) and shown digital images, corresponding CIE color coordinates (red region) as well as obtained highest quantum yield of the thin film (78.7%).

Three-dimensional GaN dodecagonal ring structures for highly efficient phosphor-free warm white light-emitting diodes

Nanoscale ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 4686-4695 ◽  
Author(s):  
Young Chul Sim ◽  
Seung-Hyuk Lim ◽  
Yang-Seok Yoo ◽  
Min-Ho Jang ◽  
Sunghan Choi ◽  
...  
Keyword(s):  
White Light ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Three Dimensional ◽  
Light Emitting ◽  
White Leds ◽  
Highly Efficient ◽  
Warm White Light ◽  
Ring Structures ◽  
White Light Emitting Diodes

Multifaceted dodecagonal ring structures emit light of various colours with high efficiency and are demonstrated to be phosphor-free white LEDs.

Color Tuning of Biomass-Derived Carbon Nanodots by Reaction Temperature Toward White Light-Emitting Diodes

NANO ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. 2050159
Author(s):  
Yi Gong ◽  
Yanbing Han ◽  
Fang Zhang ◽  
Mingyue Zhai ◽  
Xing Chen ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
White Light ◽  
Heating Temperature ◽  
Light Emitting Diode ◽  
Peak Position ◽  
Carbon Nanodots ◽  
One Pot ◽  
Light Emitting ◽  
White Leds ◽  
Band Emission

In this work, carbon nanodots (CNDs) were synthesized from extract of mango leaves. Sphere nanodots were formed rapidly by one-step microwave heating. The photoluminescence (PL) of the CNDs was found greatly dependent on the reaction temperature. The emission peak position of the CNDs changed from 550[Formula: see text]nm to 430[Formula: see text]nm when the heating temperature increased from 120[Formula: see text]C to 150[Formula: see text]C. Particularly, the CNDs synthesized at 130[Formula: see text]C showed multi-band emission at 411[Formula: see text]nm, 480[Formula: see text]nm and 530[Formula: see text]nm, providing emitting color from blue to yellow. Moreover, the free chlorophyll molecules in the solution added red fluorescence at 670[Formula: see text]nm, and the integrated emitting color of the CNDs solution was close to white. Coated on a commercial 365[Formula: see text]nm light-emitting diode (LED) chip, the CNDs showed greenish white light with CIE coordinates of (0.37, 0.44). This work provided a one-pot, rapid and green method to obtain multi-emissive CNDs toward white LEDs.

Novel polygonal structure Mn4+ activated In3+-based Elpasolite-type hexafluorides red phosphor for warm white light-emitting diodes (WLEDs)

2019 ◽  
Vol 48 (4) ◽  
pp. 1376-1385 ◽  
Author(s):  
Feng Hong ◽  
Haiming Cheng ◽  
Chao Song ◽  
Guixia Liu ◽  
Wensheng Yu ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Synthetic Methods ◽  
Red Phosphor ◽  
Light Emitting ◽  
White Leds ◽  
Red Phosphors ◽  
Polygonal Structure ◽  
Warm White Light ◽  
White Light Emitting Diodes

Red phosphors (NH4)2NaInF6:Mn4+ with controllable morphology were synthesized via different synthetic methods, which can be fabricated for warm white LEDs.

Discomfort glare caused by white LEDs having different spectral power distributions

2017 ◽  
Vol 50 (6) ◽  
pp. 921-936 ◽  
Author(s):  
WJ Huang ◽  
Y Yang ◽  
M Ronnier Luo
Keyword(s):  
White Light ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
White Leds ◽  
Significant Difference ◽  
Discomfort Glare ◽  
Led Lights ◽  
Green Leds

This paper describes an experiment to investigate discomfort glare caused by white light-emitting diode (LED) lights having different spectral power distributions. It included two groups: a ‘Metamerism’ group and a ‘correlated colour temperatures (CCT)’ group. In the former group, it was found that white lights at 7000 K constructed from different blue LEDs and the same red and green LEDs gave about the same glare perception. In the latter group, there was a significant difference in glare perception between white lights having different CCTs. Finally, glare models, including unified glare rating (UGR) and the newly derived QUGRspd, and mUGRspd models, were tested using the data from the experiment. All of them gave quite accurate predictions of the data.

Synthesis, structure and luminescence properties of new blue-green-emitting garnet-type Ca3Zr2SiGa2O12:Ce3+ phosphor for near-UV pumped white-LEDs

RSC Advances ◽  
2016 ◽  
Vol 6 (3) ◽  
pp. 2155-2161 ◽  
Author(s):  
Jiyou Zhong ◽  
Weidong Zhuang ◽  
Xianran Xing ◽  
Ronghui Liu ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Luminescence Properties ◽  
Light Emitting ◽  
White Leds ◽  
White Light Emitting Diodes

A new blue-green-emitting garnet-type phosphor Ca3Zr2SiGa2O12:Ce3+ has been explored for n-UV pumped white light-emitting diodes.

scholarly journals Preparation of Bismuth Oxide Photocatalyst and Its Application in White-light LEDs

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yen-Chang Chu ◽  
Gang-Juan Lee ◽  
Chin-Yi Chen ◽  
Shih-Hsin Ma ◽  
Jerry J. Wu ◽  
...  
Keyword(s):  
Bismuth Oxide ◽  
White Light ◽  
Front Surface ◽  
Color Temperature ◽  
Spray Pyrolysis Method ◽  
Light Emitting ◽  
White Leds ◽  
Air Purifier ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

Bismuth oxide photocatalysts were synthesized and coated on the front surface of phosphor-converted white light-emitting diodes to produce a safe and environmentally benign lighting source. Bismuth oxide photocatalyst powders were synthesized with a spray pyrolysis method at 500°C, 600°C, 700°C, and 800°C. Using the absorption spectrum in the blue and UV regions of the bismuth oxide photocatalysts, the blue light and UV leakage problems of phosphor-converted white LEDs can be significantly reduced. The experimental results showed that bismuth oxide photocatalyst synthesized at 700°C exhibited the most superior spectrum inhibiting ability. The suppressed ratio reached 52.33% in the blue and UV regions from 360 to 420 nm. Related colorimetric parameters and the photocatalyst decomposition ability of fabricated white-light LEDs were tested. The CIE chromaticity coordinates(x,y)were (0.349, 0.393), and the correlated color temperature was 4991 K. In addition, the coating layer of photocatalyst can act as an air purifier and diffuser to reduce glare. A value of66.2±0.60 ppmv of molecular formaldehyde gas can be decomposed in 120 mins.

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