scholarly journals Recycling the GaN Waste from LED Industry by Pressurized Leaching Method

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 861 ◽  
Author(s):  
Wei-Sheng Chen ◽  
Li-Lin Hsu ◽  
Li-Pang Wang
Keyword(s):  
Energy Gap ◽  
Light Emitting Diode ◽  
Economic Value ◽  
Acid Leaching ◽  
High Hardness ◽  
High Energy ◽  
Light Emitting ◽  
Valuable Metals ◽  
Leaching Solution ◽  
Leaching Efficiency

In recent years, with the increasing research and development of the light-emitting diode (LED) industry, which contains gallium nitride (GaN), it is expected that there will be a large amount of related wastes in the future. Gallium has an extremely high economic value, therefore, it is necessary to establish a recycling system for the GaN waste. However, GaN is a direct-gap semiconductor and with its high energy gap, high hardness, and high melting point, these make it difficult to recycle. Therefore, this study will analyze the physical characteristics of LED wastes containing GaN and carry out various leaching methods to leach the valuable metals from the waste optimally. Different acids are used to find out the best reagent for gallium leaching. Different experimental parameters are discussed, such as the effect of the different acid agents, concentration, pressure, liquid-solid mass ratio, temperature and time, which influence the leaching efficiency of gallium. Finally, acid leaching under high pressure is preferred to leach the GaN waste, and hydrochloric acid is used as the leaching solution because of its better leaching efficiency of gallium. Optimally, the leaching efficiency of gallium can reach 98%.

scholarly journals Recycling the Gan Waste from LED Industry by Pressurized Leaching Method

2018 ◽  
Author(s):  
Wei-Sheng Chen ◽  
Li-Lin Hsu ◽  
Li-Pang Wang
Keyword(s):  
Energy Gap ◽  
Acid Leaching ◽  
High Hardness ◽  
High Energy ◽  
Advantages And Disadvantages ◽  
Valuable Metals ◽  
Leaching Solution ◽  
Leaching Methods ◽  
Solid Liquid ◽  
Leaching Efficiency

In recent years, with the increasing research and development of the LED industry which contains GaN, it is expected that there will be a large amount of related wastes in the future. Especially the gallium has extremely high value of economic, therefore, it is necessary to establish the recycling system of the GaN waste. However, GaN is a direct-gap semiconductor and with high energy gap, high hardness, and high melting point make it difficult to recycle. Therefore, this study will analyze the physical characteristics of LED wastes containing GaN and carry out various leaching method to leach the valuable metals from the waste optimally. Different acids are used to find out the best reagent for leaching the gallium. Different experimental parameters are discussed such as the effect of the different acid agents , concentration, pressure, solid-liquid mass ratio, temperature, and time which influence the leaching efficiency of the gallium. In this study, various leaching methods which effect the leaching efficiency of the gallium are compared and the advantages and disadvantages are discussed. Finally, pressurized acid leaching method is preferred to leach the GaN waste, and hydrochloric acid is used as the leaching solution because of its better leaching efficiency of gallium. Eventually, the leaching efficiency of the gallium can reach to 98%.

Visible-Light Amorphous Silicon-Nitride Thin Film Light Emitting Diode

1993 ◽  
Vol 297 ◽  
Author(s):  
Wirote Boonkosum ◽  
Dusit Kruangam ◽  
Somsak Panyakeow
Keyword(s):  
Thin Film ◽  
Visible Light ◽  
Energy Gap ◽  
Light Emitting Diode ◽  
Carrier Injection ◽  
Optical Energy Gap ◽  
Recombination Mechanism ◽  
Light Emitting ◽  
Orange Yellow ◽  
Emission Color

A visible-light Thin Film Light Emitting Diode (TFLED) having a-SiN:H as a luminescent active layer has been developed. The TFLED has a structure of glass substrate/ITO/p a-SiC:H/i a-SiN:H/n a-SiC:H/Al. The emission color could be changed from red to orange, yellow, green and white-blue by varying the optical energy gap of the i a-SiN:H layer in the TFLED. The brightness was in the order of 0.1-1 cd/m2 . A series of systematic investigations on the basic properties of a-SiN:H films carrier injection and recombination mechanism in TFLEDs is described.

Highly Efficient Phosphorescent Green Organic Light-Emitting Diodes with High Energy Gap Host Materials

2010 ◽  
Vol 530 (1) ◽  
pp. 83/[239]-90/[246]
Author(s):  
Hoe Min Kim ◽  
Ji Hyun Seo ◽  
Kum Hee Lee ◽  
Hyun Ju Kang ◽  
Seung Soo Yoon ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Energy Gap ◽  
High Energy ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Highly Efficient ◽  
Organic Light ◽  
Host Materials

Metasurface integrated high energy efficient and high linearly polarized InGaN/GaN light emitting diode

Nanoscale ◽  
2017 ◽  
Vol 9 (26) ◽  
pp. 9104-9111 ◽  
Author(s):  
Miao Wang ◽  
Fuyang Xu ◽  
Yu Lin ◽  
Bing Cao ◽  
Linghua Chen ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Light Emitting Diode ◽  
High Energy ◽  
Light Emitting ◽  
Linearly Polarized

The Effect of Needle Diameter on Optical Properties and Morphological Structure of La2O3- PVA Phosphor Nanofibers Prepared by Electrospinning Method

2020 ◽  
Vol 301 ◽  
pp. 18-26
Author(s):  
Hasma A. Wahab ◽  
Zainuriah Hassan ◽  
Naser Mahmoud Ahmed
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Morphological Structure ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Electrospinning Method ◽  
Needle Diameter

Lanthanum Oxide-Polyvinyl alcohol (La2O3-PVA) phosphor nanofibers were prepared by electrospinning and investigation of the effect of needle diameter on the optical properties and morphological structure at the nanofibers was carried out. The average diameter of phosphor nanofibers have been evaluated for five different needle diameters. The resulting phosphor nanofibers were observed and anaylzed by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Ultraviolet-visible Spectroscopy (UV-Vis) and HPC-2 Lightsource Colorimeter. The La2O3-PVA phosphor nanofibers were used in light down-conversion of UV light (365 nm) for the white light-emitting diode (WLED) application. The chromaticity coordinates (CIE) and correlated colour temperature (CCT) were measured for different phosphor nanofibers with different sizes of needle diameter (0.45,0.55,0.65,0.75,1.1) mm. The results revealed that the phosphor nanofibers formed by needle diameter of 0.65 mm places macromolecule in a better order and the average diameter increase from 40.08 nm to 87.27 nm after annealing followed by increasing in atomic percentage of lanthanum. The energy gap of resulting phosphor nanofibers is 3.5365 eV. An optimum colour rendering index (CRI) value of 70.20 is obtained. The white phosphor exhibited CIE values of 0.3536, 0.407 and CCT of 4890 K.

Junction Temperature Measurements in Deep-UV Light-Emitting Diodes

2004 ◽  
Vol 831 ◽  
Author(s):  
Y. Xi ◽  
J.-Q. Xi ◽  
Th. Gessmann ◽  
J. M. Shah ◽  
J. K. Kim ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Energy Gap ◽  
Uv Light ◽  
Accurate Method ◽  
High Energy ◽  
Junction Temperature ◽  
Forward Voltage ◽  
Light Emitting ◽  
Thermal Paste ◽  
Carrier Temperature

ABSTRACTThe junction temperature of AlGaN/GaN ultraviolet (UV) Light-Emitting Diodes (LEDs) emitting at 295 nm is measured by using the temperature coefficients of the diode forward voltage and emission peak energy. The high-energy slope of the spectrum is explored to measure the carrier temperature. A linear relation between junction temperature and current is found. Analysis of the experimental methods reveals that the diode-forward voltage is the most accurate method (± 3 °C). A theoretical model for the dependence of the diode junction voltage (Vj) on junction temperature (T) is developed that takes into account the temperature dependence of the energy gap. A thermal resistance of 87.6 K/W is obtained with the AlGaN/GaN LED sample mounted with thermal paste on a heat sink.

Study on Recovering of Value Metals from Acid Leaching Solution of Roasted Electroplating Sludge

2012 ◽  
Vol 524-527 ◽  
pp. 1951-1955 ◽  
Author(s):  
Xiao E Dang ◽  
Xin Zhe Lan ◽  
Yuan Dong
Keyword(s):  
Recovery Rate ◽  
Acid Leaching ◽  
Recovery Process ◽  
Zinc Powder ◽  
Environmental Benefits ◽  
Pollution Problem ◽  
Valuable Metals ◽  
Electroplating Sludge ◽  
Environmental Pollution Problem ◽  
Leaching Solution

Chelating electroplating sludge contains high grade of toxic metals or heavy metals, so this sludge should be treated and recovered of valuable metals from it. This paper mainly studied on the recovery process of Copper, Nickel and Zinc process from sulfuric acid leaching solution of roasted chelating electroplated sludge. It provided an effective technique for recovery of valuable metals from acid leaching solution. The efficiency of the process had been measured with the metal recovery rate. Experimental results showed that recovery rate of Copper and Nickel can respectively achieve at 99.30% and 97.00% from acid leaching solution after removal iron with zinc powder used reducing agent. The process has simple operation and high recovery rate. It can solve the environmental pollution problem of electroplating sludge and valuable metals can be recovered from which. It could bring better economic and environmental benefits to the enterprise.

scholarly journals Cell Phone Acne: New Acne Clinical Features in the Coronavirus Disease-19 Era

2021 ◽  
Vol 9 (F) ◽  
pp. 481-485
Author(s):  
Kristin Stephanie Sembiring ◽  
Nelva Karmila Jusuf
Keyword(s):  
Cell Phone ◽  
Heat Dissipation ◽  
Prolonged Exposure ◽  
Light Emitting Diode ◽  
Electronic Devices ◽  
High Energy ◽  
Light Spectrum ◽  
Oil Accumulation ◽  
Light Emitting ◽  
Technological Developments

Technological developments in telecommunications, especially cell phone, enable us to keep communicate without meeting each other. Especially during the latest coronavirus outbreak, when people need to keep up social distance. Meanwhile, electronic devices such as smartphone, tablets, laptops, and light-emitting diode screens are the sources of visible lights that can emit high levels of short-wavelength visible light (blue region in the light spectrum). Prolonged exposure to high-energy blue light, heat dissipation from cell phone, friction, trapped sweat and oil, accumulation of dust, and increased bacterial growth can cause cell phone acne. Management of cell phone acne from prevention to combination therapy based on the results of the evaluation of the severity of acne is needed.

scholarly journals Improved Exposure To Blue Light For Bacterial Death Of Staph

2019 ◽  
Vol 21 (1) ◽  
pp. 13
Author(s):  
Endah Robbiyati
Keyword(s):  
Staphylococcus Aureus ◽  
Light Source ◽  
Blue Light ◽  
Staphylococcus Epidermidis ◽  
Energy Analysis ◽  
Light Emitting Diode ◽  
High Energy ◽  
Light Emitting ◽  
Blue Led ◽  
Correct Energy

ABSTRACTIn this study, bacteria Gram-positive Staphylococcus aureus is exposed to a blue LED light source (light-emitting diode) to determine the appropriate energy to kill the exposure-caused bacteria. The longest exposure times are 1200, 1800, 2400, 3000 seconds, and power 28.098, 56.561, 74.882, and 96.369 MW. The number of bacterial colonies incubated by TPC (total plate number) at 37 degrees 24-48 hours while the plant is alive. Determine the correct energy caused by exposure to the blue LED lamp, therefore, perform mold analysis, non-compliance, and quantitative energy analysis. These results show that the death of streptococcus skin is generally affected by high energy. From this study, we found that 74,882 MW of energy and 179,716.8 MJ of bacteria per 2,400 seconds were the best energy week.Keywords: Staphylococcus epidermidis, a blue LED, exposure time, the power of                   exposure, CFU

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