Recent Advances in A-Si Solar Cell Technology in Japan

1986 ◽  
Vol 70 ◽  
Author(s):  
Y. Kuwano

ABSTRACTRecent advances in a-Si solar cells in Japan are reviewed. Improvements in single-junction and multi-junction solar cells are described in three main points, namely, fabrication methods, materials, and cell structures. Recently, a conversion efficiency of 11.7% was obtained for a single-junction structure. For an a-Si/poly-Si stacked structure and an a-Si/(CdS/CdTe) 4 terminal structure, conversion efficiencies of more than 13% were achieved.Then recent advances in the prevention of the light induced degradation of a-Si solar cells is mentioned. Several methods which can improve the a-Si solar cell stability are described.Finally, the present status of the industrialization of a-Si solar cells and some of the latest applications are described together with their propects.

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3397 ◽  
Author(s):  
Jong Lim ◽  
Woo Shin ◽  
Hyemi Hwang ◽  
Young-Chul Ju ◽  
Suk Ko ◽  
...  

Cut solar cells have received considerable attention recently as they can reduce electrical output degradation when the c-Si solar cells (crystalline-silicon solar cells) are shaded. Cut c-Si solar cells have a lower short-circuit current than normal solar cells and the decrease in short-circuit currents is similar to the shading effect of c-Si solar cells. However, the results of this study’s experiment show that the shadow effect of a c-Si solar cell reduces the V o c (open circuit voltage) in the c-Si solar cell but the V o c does not change when the c-Si solar cell is cut because the amount of incident light does not change. In this paper, the limitations of the electrical power analysis of the cut solar cells were identified when only photo current was considered and the analysis of the electric output of the cut c-Si solar cells was interpreted with a method different from that used in previous analyses. Electrical output was measured when the shaded and cut rates of c-Si solar cells were increased from 0% to 25, 50 and 75%, and a new theoretical model was compared with the experimental results using MATLAB.


Author(s):  
Hisaaki Nishimura ◽  
Takaya Maekawa ◽  
Kazushi Enomoto ◽  
Naoteru Shigekawa ◽  
Tomomi Takagi ◽  
...  

The sensitivity of Si solar cells to the UV portion of the solar spectrum is low, and must be increased to further improve their efficiencies.


2007 ◽  
Vol 989 ◽  
Author(s):  
Ivan Gordon ◽  
Lode Carnel ◽  
Dries Van Gestel ◽  
Guy Beaucarne ◽  
Jef Poortmans

AbstractEfficient thin-film polycrystalline-silicon (pc-Si) solar cells on inexpensive substrates could lower the price of photovoltaic electricity substantially. At the MRS conference in 2006, we presented a pc-Si solar cell with an efficiency of 5.9% that had an absorber layer made by aluminum-induced crystallization (AIC) of amorphous silicon followed by high-temperature epitaxial thickening. The efficiency of this cell was mainly limited by the current density. To obtain higher efficiencies, we therefore need to implement an effective light trapping scheme in our pc-Si solar cell process. In this work, we describe how we recently enhanced the current density and efficiency of our cells. We achieved a cell efficiency of 8.0% for pc-Si cells in substrate configuration. Our cell process is based on pc-Si layers made by AIC and thermal CVD on smoothened alumina substrates. The cells are in substrate configuration with deposited a-Si heterojunction emitters and interdigitated top contacts. The front surface of the cells is plasma textured which leads to an increase in current density. The current density is further enhanced by minimizing the back surface field thickness of the cells to reduce the light loss in this layer. Our present pc-Si solar cell efficiency together with the fast progression that we have made over the last few years indicate the large potential of pc-Si solar cells based on the AIC seed layer approach.


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.


2004 ◽  
Vol 449-452 ◽  
pp. 1013-1016 ◽  
Author(s):  
Gee Keun Chang

With new models of AM1 solar spectra and Si refractive indices in the wavelength range of 0.4 0.97 , effective absorption powers of Si solar cells coated with the single and double AR layers were theoretically calculated for the first time. The SiO2, Si3N4 and SiO2/Si3N4 easily obtainable in the standard Si process were used as the AR layers of Si solar cell. Optimum thicknesses showing the maximum absorption power for AR layers of SiO2, Si3N4 and SiO2/Si3N4 were as follows: d(SiO2)=10001, d(Si3N4)=7001 and d(SiO2/Si3N4) =500 1 /3001 . Effective absorption powers in the solar cells of SiO2-Si, Si3N4-Si and SiO2/Si3N4-Si were 520W/m2, 565W/m2 and 607W/m2 at AM1 in the optimum conditions of AR coating, respectively


2012 ◽  
Vol 725 ◽  
pp. 149-152 ◽  
Author(s):  
Futoshi Okayama ◽  
Michio Tajima ◽  
Hiroyuki Toyota ◽  
Atsushi Ogura

We demonstrated high-speed imaging of photoluminescence (PL) and electroluminescence (EL) for not only band-to-band but also multiple deep-level emissions in a multicrystalline Si solar cell. We used a cooled InGaAs camera with a photosensitive range of 900 - 1700 nm equipped with band-pass filters for the selective detection of various deep-level emissions. The exposure time for imaging was only 1 - 10 seconds. Comparisons of the present PL images with the microscopic PL mappings confirmed for us that essentially the same luminescence patterns were obtained.


Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1593 ◽  
Author(s):  
Jong Rok Lim ◽  
Sihan Kim ◽  
Hyung-Keun Ahn ◽  
Hee-Eun Song ◽  
Gi Hwan Kang

The silicon wafers for solar cells on which the paste is deposited experience a bowing phenomenon. The thickness of commonly used c-Si wafers is 180 μm or more. When fabricating c-Si solar cells with this wafer thickness, the bowing value is 3 mm or less and the problem does not occur. However, for the thin c-Si solar cells which are being studied recently, the output reduction due to failure during manufacture and cracking are attributed to bowing. In generally, it is known that the bowing phenomenon arises mainly from the paste applied to the back side electrode of c-Si solar cells and the effects of SiNx (silicon nitride) and the paste on the front side are not considered significant. The bowing phenomenon is caused by a difference in the coefficient of expansion between heterogeneous materials, there is the effect of bowing on the front electrode and ARC. In this paper, a partially processed c-Si solar cell was fabricated and a bowing phenomenon variation according to the wafer thicknesses was confirmed. As a result of the experiment, the measured bow value after the firing process suggests that the paste on the front-side indicates a direction different from that of the back-side paste. The bow value increases when Al paste is deposited on SiNx. The fabricated c-Si solar cell was analyzed on basis of the correlation between the bowing phenomenon of the materials and the c-Si wafer using Stoney’s equation, which is capable of analyzing the relationship between bowing and stress. As a result, the bowing phenomenon of the c-Si solar cell estimated through the experiment that the back side electrode is the important element, but also the front electrode and ARC influence the bowing phenomenon when fabricating c-Si solar cells using thin c-Si wafers.


1999 ◽  
Vol 557 ◽  
Author(s):  
Bhushan Sopori ◽  
Jamal Madjdpour ◽  
Yi Zhang ◽  
Wei Chen ◽  
Subhendu Guha ◽  
...  

AbstractWe describe applications of PV Optics to analyze the behavior of a metallic back-reflector on an a-Si solar cell. The calculated results from PV Optics agree well with the measured data on solar cells. Several unexpected results obtained from these calculations are qualitatively explained.


2008 ◽  
Vol 1123 ◽  
Author(s):  
Bhushan Sopori ◽  
Vishal Mehta ◽  
Przemyslaw Rupnowski ◽  
Helio Moutinho ◽  
Aziz Shaikh ◽  
...  

AbstractWe have studied mechanisms of back-contact formation in screen-printed Si solar cells by a fire-through process. An optimum firing temperature profile leads to the formation of a P-Si/P+- Si/ Si-Al eutectic/agglomerated Al at the back contact of a Si solar cell. Variations in the interface properties were found to arise from Al-Si melt instabilities. Experiments were performed to study melt formation. We show that this process is strongly controlled by diffusion of Si into Al. During the ramp-up, a melt is initiated at the Si-Al interface, which subsequently expands into Al and Si. During the ramp-down, the melt freezes, which causes the doped region to grow epitaxially on Si, followed by solidification of the Si-Al eutectic. Any agglomerated (or sintered) Al particles are dispersed with Si. Implications on the performance of the cell are described.


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