Near-Field Electroluminescent Refrigeration System Consisting of Two Graphene Schottky Diodes

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Jaeman Song ◽  
Junho Jang ◽  
Mikyung Lim ◽  
Jungchul Lee ◽  
Seung S. Lee ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Near Field ◽  
Schottky Diodes ◽  
Electrical Power ◽  
Coefficient Of Performance ◽  
Semiconductor Diode ◽  
Design Parameters ◽  
Refrigeration System ◽  
Surface Polaritons ◽  
Light Emitting

Abstract It has been shown that the performance of a thermal radiative device, such as a thermophotovoltaic (TPV) and an electroluminescent (EL) refrigerator, can be significantly enhanced when the vacuum gap between a reservoir and a semiconductor diode becomes nanoscale. Recently, several studies have reported the integration of a TPV and a light emitting diode (LED) in one near-field thermal radiative device to improve the operation efficiency. However, surface polaritons were hardly exploited in previous research because bare semiconductor diodes were used. In this paper, we propose a TPV-LED integrated near-field EL refrigeration system consisting of two graphene-semiconductor Schottky diodes. A substantial refrigeration rate (101.9 kW/m2) is achieved owing to the coupling of surface plasmon-phonon polaritons excited by a symmetric configuration of graphene-polar materials. Moreover, the cooling coefficient of performance (COP) of the system can be enhanced up to 2.65 times by recycling the electrical power generated in the TPV cell. The cooling performance is further investigated in relation to design parameters, namely the doping concentration of Si and insulator thickness.

Spatial Inhomogeneity of Photoluminescence in an InGaN-Based Light-Emitting Diode Structure Probed by Near-Field optical Microscopy Under Illumination-Collection Mode

2001 ◽  
Vol 40 (Part 1, No. 1) ◽  
pp. 110-111 ◽  
Author(s):  
Akio Kaneta ◽  
Tomoaki Izumi ◽  
Koichi Okamoto ◽  
Yoichi Kawakami ◽  
Shigeo Fujita ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Light Emitting Diode ◽  
Near Field ◽  
Diode Structure ◽  
Spatial Inhomogeneity ◽  
Light Emitting

Research note: Light emitting diodes as solar power resources

2018 ◽  
Vol 51 (3) ◽  
pp. 476-483
Author(s):  
RK Salman
Keyword(s):  
Environmental Pollution ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Electronic Devices ◽  
Electrical Power ◽  
Lemon Yellow ◽  
Angle Of Incidence ◽  
Solar Panels ◽  
Light Emitting ◽  
Power Resources

This paper investigates the possibility of recycling light emitting diodes from damaged electronic devices, and using them in a similar way to photovoltaic cells in order to reduce environmental pollution. The study used a number of tests with a variety of different parameters for measuring the capability for light emitting diodes to harvest the sun’s rays and to convert them into a useful form of electrical power. The different configurations involved variations of light emitting diode wavelength and number, as well as the connection types between the light emitting diodes (series and parallel) and the angle of incidence of the sun’s rays to the light emitting diode’s base. The results showed promising voltage data for parallel-connected light emitting diodes of lemon (yellow-green) and green colour. The variations in voltage produced by tilting the light emitting diode’s base exhibited similar behaviour to that seen in solar panels. The power that was harvested from the light emitting diodes was extremely low, but the voltage gains showed promising trends that could be employed in useful applications. Hence, light emitting diodes could be re-used to reduce environmental pollution and thus to contribute towards environmental enhancement.

scholarly journals Exergy and Exergoeconomic Analysis of a Cogeneration Hybrid Solar Organic Rankine Cycle with Ejector

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 702
Author(s):  
Bourhan Tashtoush ◽  
Tatiana Morosuk ◽  
Jigar Chudasama
Keyword(s):  
Electrical Power ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Refrigeration System ◽  
Entrainment Ratio ◽  
Temperature And Pressure

Solar energy is utilized in a combined ejector refrigeration system with an organic Rankine cycle (ORC) to produce a cooling effect and generate electrical power. This study aims at increasing the utilized share of the collected solar thermal energy by inserting an ORC into the system. As the ejector refrigeration cycle reaches its maximum coefficient of performance (COP), the ORC starts working and generating electrical power. This electricity is used to run the circulating pumps and the control system, which makes the system autonomous. For the ejector refrigeration system, R134a refrigerant is selected as the working fluid for its performance characteristics and environmentally friendly nature. The COP of 0.53 was obtained for the ejector refrigeration cycle. The combined cycle of the solar ejector refrigeration and ORC is modeled in EBSILON Professional. Different parameters like generator temperature and pressure, condenser temperature and pressure, and entrainment ratio are studied, and the effect of these parameters on the cycle COP is investigated. Exergy, economic, and exergoeconomic analyses of the hybrid system are carried out to identify the thermodynamic and cost inefficiencies present in various components of the system.

scholarly journals Mobilizing Skin Care: Measuring and Tracking External Conditions with Light Emitting Diodes

2019 ◽  
Vol 6 (2) ◽  
pp. 17
Author(s):  
Stephen J McNeill
Keyword(s):  
Uv Light ◽  
Respiratory Health ◽  
Light Emitting Diode ◽  
Near Field ◽  
Free Water ◽  
The United States ◽  
Skin Care ◽  
Uv Index ◽  
Light Emitting ◽  
External Conditions

Light emitting diode (LED) technology allows users to monitor their indoor and outdoor environments while engaged in various tasks. LED has long been touted for its direct benefits to the skin; now, new LED technology is monitoring many external conditions that directly relate to human skin and respiratory health. My Skin Track UV, from La Roche Posay, is an integrated near-field communication (NFC) app. The light emitting diode (LED) acts as a detector to capture UV light. The battery-free, water-proof LED is worn on clothing and the energy is read by transferring data from the sensor to a smartphone via NFC technology. Based on one’s UV exposure and other environmental factors, the app uses a closed-loop, proprietary algorithm to issue a notification when environmental exposure is at a level that contributes to the users’ specific skin concerns. Skin cancer is the most common form of cancer in the United States and is the easiest to prevent. My Skin Track UV measures UVA and UVB exposure, noting the maximum percentage of sun-stock – the recommended maximum daily allowance of UV based on skin tone and the UV index. It also tracks pollen, pollution, temperature, and humidity. This paper discusses application of LED and NFC technology and reviews similar skin care applications and health education, including uses and gratifications. The associated paper features background technological research behind the evolution of smart-phone UV skin monitoring. The paper also includes results from product demonstration.

scholarly journals Modeling and Simulations of 4H-SiC/6H-SiC/4H-SiC Single Quantum-Well Light Emitting Diode Using Diffusion Bonding Technique

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1499
Author(s):  
Muhammad Haroon Rashid ◽  
Ants Koel ◽  
Toomas Rang ◽  
Nadeem Nasir ◽  
Haris Mehmood ◽  
...  
Keyword(s):  
Quantum Well ◽  
Power Efficiency ◽  
Semiconductor Device ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Design Parameters ◽  
Diffusion Welding ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Light Emitting

In the last decade, Silicon carbide (SiC) has emerged as a potential material for high-frequency electronics and optoelectronics applications that may require elevated temperature processing. SiC exists in more than 200 different crystallographic forms, referred to as polytypes. Based on their remarkable physical and electrical characteristics, such as better thermal and electrical conductivities, 3C-SiC, 4H-SiC, and 6H-SiC are considered as the most distinguished polytypes of SiC. In this article, physical device simulation of a light-emitting diode (LED) based on the unique structural configuration of 4H-SiC and 6H-SiC layers has been performed which corresponds to a novel material joining technique, called diffusion welding/bonding. The proposed single quantum well (SQW) edge-emitting SiC-based LED has been simulated using a commercially available semiconductor device simulator, SILVACO TCAD. Moreover, by varying different design parameters, the current-voltage characteristics, luminous power, and power spectral density have been calculated. Our proposed LED device exhibited promising results in terms of luminous power efficiency and external quantum efficiency (EQE). The device numerically achieved a luminous efficiency of 25% and EQE of 16.43%, which is at par performance for a SQW LED. The resultant LED structure can be customized by choosing appropriate materials of varying bandgaps to extract the light emission spectrum in the desired wavelength range. It is anticipated that the physical fabrication of our proposed LED by direct bonding of SiC-SiC wafers will pave the way for the future development of efficient and cost-effective SiC-based LEDs.

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