scholarly journals Limiting Solar Cell Heat-Up by Quantizing High Energy Carriers

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
L. Devarakonda ◽  
S. Mil'shtein

Under solar radiation the efficiency of solar cells decreases as a result of heating up by short wavelengths photons. To minimize loss of efficiency with increasing temperatures, we designed a heterostructure AlGaAs/AlGaAs/GaAs cascaded p-i-n solar cells with 30 Å wide quantum wells and 10 Å wide barriers in p and i regions. Our modeling demonstrated that quantizing high energy carriers in the superlattice prevents scattering of excessive electron energies, thus decreasing the temperature rise per unit of time by a factor of 2. The modeling based on continuity equations included integration of absorption coefficients for various wavelengths and summarizes all thermodynamic heat exchanges in the designed solar cell.

2021 ◽  
Vol 26 (4) ◽  
pp. 113-119
Author(s):  
FRANK ONAIFO ◽  
AKPOFURE ALEXANDER OKANDEJI ◽  
OLAMIDE AJETUNMOBI ◽  
DAVID BALOGUN

This paper studies the effect of temperature, humidity and irradiance on the power generated by a photovoltaic solar cell. This was achieved using pyranometer for determining the solar radiation, wet and dry thermometer for measuring humidity, and digital multimeter for voltage and current measurement. The result of the study show that power generation increases with increase of solar irradiance. Additionally, changes of humidity level and temperature do not significantly affect solar power generation. Furthermore, it was also observed that high temperatures and higher humidity levels accelerate the corrosion process on the solar cells which reduces the efficiency of the cells.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Tchouadep Guy Serge ◽  
Zouma Bernard ◽  
Korgo Bruno ◽  
Soro Boubacar ◽  
Savadogo Mahamadi ◽  
...  

The aim of this work is to study the behaviour of a silicon solar cell under the irradiation of different fluences of high-energy proton radiation (10 MeV) and under constant multispectral illumination. Many theoretical et experimental studies of the effect of irradiation (proton, gamma, electron, etc.) on solar cells have been carried out. These studies point out the effect of irradiation on the behaviour of the solar cell electrical parameters but do not explain the causes of these effects. In our study, we explain fundamentally the causes of the effects of the irradiation on the solar cells. Taking into account the empirical formula of diffusion length under the effect of high-energy particle irradiation, we established new expressions of continuity equation, photocurrent density, photovoltage, and dynamic junction velocity. Based on these equations, we studied the behaviour of some electronic and electrical parameters under proton radiation. Theoretical results showed that the defects created by the irradiation change the carrier distribution and the carrier dynamic in the bulk of the base and then influence the solar cell electrical parameters (short-circuit current, open-circuit voltage, conversion efficiency). It appears also in this study that, at low fluence, junction dynamic velocity decreases due to the presence of tunnel defects. Obtained results could lead to improve the quality of the junction of a silicon solar cell.


2016 ◽  
Vol 3 ◽  
pp. 64-85
Author(s):  
Liam Caruana ◽  
Thomas Nommensen ◽  
Toan Dinh ◽  
Dennis Tran ◽  
Robert McCormick

In the 21st century, global energy consumption has increased exponentially and hence, sustainable energy sources are essential to accommodate for this. Advancements within photovoltaics, in regards to light trapping, has demonstrated to be a promising field of dramatically improving the efficiency of solar cells. This improvement is done by using different nanostructures, which enables solar cells to use the light spectrum emitted more efficiently. The purpose of this meta study is to investigate irreversible entropic losses related to light trapping. In this respect, the observation is aimed at how nanostructures on a silicon substrate captures high energy incident photons. Furthermore, different types of nanostructures are then investigated and compared, using the étendue ratio during light trapping. It is predicted that étendue mismatching is a parasitic entropy generation variable, and that the matching has an effect on the open circuit voltage of the solar cell. Although solar cells do have their limiting efficiencies, according to the Shockley-Queisser theory and Yablonovitch limit, with careful engineering and manufacturing practices, these irreversible entropic losses could be minimized. Further research in energy losses, due to entropy generation, may guide nanostructures and photonics in exceeding past these limits.Keywords: Photovoltaic cell; Shockley-Queisser; Solar cell nanostructures; Solar cell intrinsic and extrinsic losses; entropy; étendue; light trapping; Shockley Queisser; Geometry; Meta-study


MRS Bulletin ◽  
1993 ◽  
Vol 18 (10) ◽  
pp. 51-55 ◽  
Author(s):  
Keith Barnham ◽  
Jenny Barnes ◽  
Guido Haarpaintner ◽  
Jenny Nelson ◽  
Mark Paxman ◽  
...  

The best present-day single-bandgap solar cells have efficiencies around 20–25%. However, the Carnot efficiency of the earth-sun system is 95%, so there is considerable potential for improvement. The fundamental efficiency limitation in a conventional solar cell results from the tradeoff between a low bandgap which maximizes light absorption and hence output current and a high bandgap which maximizes output voltage. As a result, the maximum theoretical efficiency of a conventional solar cell is around 30% in unconcentrated sunlight at a bandgap close to that of GaAs.The quantum-well solar cell is a novel approach to higher efficiency. In its simplest form, shown in Figure 1, it consists of a multiquantum-well (MQW) system in the undoped region of a p-i-n solar cell. For light with energy greater than the band-gap Eg, the quantum-well cell behaves like a conventional cell. However, light with energy below Eg can be absorbed in the quantum wells. Our studies show that if the material quality is good, the electrons and holes escape from the wells and contribute to a higher output current at a voltage between that of the barrier and well material. In AlGaAs/GaAs test devices, we have obtained efficiency enhancements of a factor of more than two when cells with quantum wells are compared with identical cells without wells.The structure in Figure 1 is, of course, essentially similar to the MQW photodiode or modulator structure that operates in reverse bias, and the quantum-well laser that operates in forward bias beyond flat band.


Author(s):  
Wail Hessen ALawad ALHessen ◽  
Abdelnabe Ali Elamin Ali ◽  
Mohammed Habib Ahmed El_kanzi

In this paper, the performance of solar cells was studied and evaluated . The role of several effects for operation condition such as temperature, sunlight intensity on the solar cells output parameters has been studied. Experimental results showed that relationship between the amount of solar cell output parameters variations such as maximum output power, open circuit voltage, short circuit current, and efficiency in terms of temperature and light intensity. The measurements were carried out for the intensity of solar radiation in Khartoum area in Sudan, from February month to April month which records the solar radiation in W/m2, The results were collected from 10 Am to 4 pm, three days per week, data were averaged and also illustrated in the form of graphs of solar radiation as a function of the time of the day. The operating temperature plays a key role in the photovoltaic conversion process. Both the electrical efficiency and the power output of the solar cell depend on the operating temperature. Solar cell performance decreases with increasing temperature.


RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 20585-20592 ◽  
Author(s):  
Ji-Hyeon Park ◽  
R. Nandi ◽  
Jae-Kwan Sim ◽  
Dae-Young Um ◽  
San Kang ◽  
...  

Solar cells fabricated with hybrid nanowires comprising InGaN/GaN uniaxial and coaxial multi-quantum wells with an InGaN nano-cap layer.


2020 ◽  
Vol 995 ◽  
pp. 71-76
Author(s):  
Aaron Glenn ◽  
Conor Mc Loughlin ◽  
Hind Ahmed ◽  
Hoda Akbari ◽  
Subhash Chandra ◽  
...  

The main energy losses in solar cells are related to spectral losses where high energy photons are not used efficiently, and energy is lost via thermalization which reduces the solar cell’s overall efficiency. A way to tackle this is to introduce a luminescent down-shifting layer (LDS) to convert these high energy photons into a lower energy bracket helping the solar cell to absorb them and thus generating a greater power output. In this paper, lumogen dye Violet 570 has been used as LDS coated films of 10μm and 60μm placed on top of Si solar cells. The dye was incorporated into polymer films of Polyvinyl Butyral (PVB) and Polymethyl Methacrylate (PMMA) after which they were tested for their absorption, transmission and emission properties. Once optimised layers had been determined, they were deposited directly onto silicon solar cells and the external quantum efficiency (EQE) of the Si solar cells were measured with and without the LDS layers. The resulting graphs have shown an increase of up to 2.9% in the overall EQE efficiency after the lumogen films had been applied.


2021 ◽  
Vol 12 (1) ◽  
pp. 83
Author(s):  
Ha Trang Nguyen ◽  
Thanh Thao Tran ◽  
Vishwa Bhatt ◽  
Manjeet Kumar ◽  
Jinwon Song ◽  
...  

Recently, in the solar energy society, several key technologies have been reported to meet a grid parity, such as cost-efficient materials, simple processes, and designs. Among them, the assistive plasmonic of metal nanoparticles (MNPs) integrating with the downshifting on luminescent materials attracts much attention. Hereby, Si-based Schottky junction solar cells are fabricated and examined to enhance the performance. CdSe/ZnS quantum dots (QDs) with different gold nanoparticles (Au NPs) sizes were incorporated on a Si light absorbing layer. Due to the light scattering effect from plasmonic resonance, the sole Au NPs layer results in the overall enhancement of Si solar cell’s efficiency in the visible spectrum. However, the back-scattering and high reflectance of Au NPs lead to efficiency loss in the UV region. Therefore, the QDs layer acting as a luminescent downshifter is deployed for further efficiency enhancement. The QDs layer absorbs high-energy photons and re-emits lower energy photons in 528 nm of wavelength. Such a downshift layer can enhance the overall efficiency of Si solar cells due to poor intrinsic spectral response in the UV region. The optical properties of Au NPs and CdSe QDs, along with the electrical properties of solar cells in combination with Au/QD layers, are studied in depth. Moreover, the influence of Au NPs size on the solar cell performance has been investigated. Upon decreasing the diameters of Au NPs, the blueshift of absorbance has been observed, cooperating with QDs, which leads to the improvement of the quantum efficiency in the broadband of the solar spectrum.


2019 ◽  
Vol 33 (2) ◽  
pp. 45-58
Author(s):  
Krishna Raj Adhikari

The measurements of solar radiation for Biratnagar (BRT), Kathmandu (KTM), Pokhara (PKR) and Jumla (JML) have been undertaken using CMP 6 pyranometers from SAHR/IOE/TU, Nepal. Solar radiation and the other meteorological data have been collected from the archives of Department of Hydrology and Meteorology, Government of Nepal (DHM/GoN) to analyze the daily Global Solar Radiation (GSR). In this study, perovskite-based solar cells with the configuration Au/SpiroOMETAD/MAPbI3/TiO2/FTO have been simulated using Solar Cell Capacitance Simulator (SCAPS). The power conversion efficiency (PCE) of the cell is found to be 22.67, 22.69, 22.77 and 22.80% in BRT, KTM, PKR and JML respectively, almost similar and better performance, whereas the solar cell performs better in JML due to the high solar irradiance.


2009 ◽  
Vol 1210 ◽  
Author(s):  
Tingyi Gu ◽  
Mohamed A El-Emawy ◽  
Kai Yang ◽  
Andreas Atintz ◽  
Luke F Lester

AbstractThe InAs/InGaAs DWELL solar cell grown by MBE is a standard pin diode structure with six layers of InAs QDs embedded in InGaAs quantum wells placed within a 200-nm intrinsic GaAs region. The GaAs control wafer consists of the same pin configuration but without the DWELL structure. The typical DWELL solar cell exhibits higher short current density while maintaining nearly the same open-circuit voltage for different scales, and the advantage of higher short current density is more obvious in the smaller cells. In contrast, the smaller size cells, which have a higher perimeter to area ratio, make edge recombination current dominant in the GaAs control cells, and thus their open circuit voltage and efficiency severely degrade. The open-circuit voltage and efficiency under AM1.5G of the GaAs control cell decrease from 0.914V and 8.85% to 0.834V and 7.41%, respectively, as the size shrinks from 5*5mm2 to 2*2mm2, compared to the increase from 0.665V and 7.04% to 0.675V and 8.17%, respectively, in the DWELL solar cells. The lower open-circuit voltage in the smaller GaAs control cells is caused by strong Shockley-Read-Hall (SRH) recombination on the perimeter, which leads to a shoulder in the semi-logarithmic dark IV curve. However, despite the fact that the DWELL and GaAs control cells were processed simultaneously, the shoulders on the dark IV curve disappear in all the DWELL cells over the whole processed wafer. As has been discussed in previous research on transport in QDs, it is believed that the DWELL cells inhibit lateral diffusion current and thus edge recombination by collection first in the InGaAs quantum well and then trapping in the embedded InAs dots. This conclusion is further supported by the almost constant current densities of the different area DWELL devices as a function of voltage.


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