The Study of Improving the Conversion Efficiency and Reducing the Thickness of the HIT Solar Cell

2011 ◽  
Vol 1288 ◽  
Author(s):  
Yasuko Hirayama ◽  
Hirotada Inoue ◽  
Kenta Matsuyama ◽  
Yasu umi Tsunomura ◽  
Daisuke Fujishima ◽  
...  

ABSTRACTIn order to reduce the power-generating cost of silicon solar cells, it is necessary to achieve a high conversion efficiency using a thinner crystalline silicon (c-Si) substrate. The HIT solar cell is an amorphous silicon (a-Si) /crystalline silicon (c-Si) heterojunction solar cell that makes it possible to realize excellent surface passivation and hence high open circuit voltage (Voc). In addition, its symmetrical structure and a low-temperature fabrication process that is under 200°C provide advantages in reducing thermal and mechanical stresses within the device so that it can easily be applied to thinner solar cells. We fabricated HIT solar cells using thin wafers from 58-98 μm, and achieved a 22.8% conversion efficiency with a HIT solar cell using a 98-μm-thick wafer, and an excellent Voc value of 0.747 V with a HIT solar cell using a 58-μm-thick wafer.

2011 ◽  
Vol 1321 ◽  
Author(s):  
Xiaodan Zhang ◽  
Guanghong Wang ◽  
Xinxia Zheng ◽  
Shengzhi Xu ◽  
Changchun Wei ◽  
...  

ABSTRACTIn this article, we present a study of boron-doped hydrogenated nanocrystalline silicon (nc-Si: H) films by very high frequency-plasma enhanced chemical vapor deposition (VHF-PECVD) using high deposition pressure. Electrical, structural and optical properties of the films were investigated. Dark conductivity as high as 2.75S/cm of p-type nc-Si: H prepared at 2.5Torr pressure has been achieved at a deposition rate of 1.75Å/s for 25nm thin film. By controlling boron and phosphorus contamination, single junction nc-Si: H solar cells incorporated p-layers prepared under high pressure and low pressure, respectively, were deposited. It has been proven that nanocrystalline silicon solar cells with incorporation of p layer prepared at high pressure has resulted in enhanced open circuit voltage, short circuit current density and subsequently high conversion efficiency. Through the optimization of the bottom solar cell and application of ZnO/Al back reflector, 10.59% initial conversion efficiency of micromorph tandem solar cell (1.027cm2) with an open circuit voltage of 1.3864V, has been fabricated, where the bottom solar cell using a high pressure p layer was deposited in a single chamber.


1994 ◽  
Vol 64 (2) ◽  
pp. 199-201 ◽  
Author(s):  
J. Zhao ◽  
A. Wang ◽  
A. Aberle ◽  
S. R. Wenham ◽  
M. A. Green

2015 ◽  
Vol 8 (1) ◽  
pp. 303-316 ◽  
Author(s):  
Abd. Rashid bin Mohd Yusoff ◽  
Dongcheon Kim ◽  
Hyeong Pil Kim ◽  
Fabio Kurt Shneider ◽  
Wilson Jose da Silva ◽  
...  

We propose that 1 + 1 + 1 triple-junction solar cells can provide an increased efficiency, as well as a higher open circuit voltage, compared to tandem solar cells.


2008 ◽  
Vol 1123 ◽  
Author(s):  
Toshihiro Kinoshita ◽  
Daisuke Ide ◽  
Yasufumi Tsunomura ◽  
Shigeharu Taira ◽  
Toshiaki Baba ◽  
...  

AbstractIn order to achieve the widespread use of HIT (Hetero-junction with I etero-Intrinsic T ntrinsic Thin-layer) solar cells, it is important to reduce the power generating cost. There are three main approaches for reducing this cost: raising the conversion efficiency of the HIT cell, using a thinner wafer to reduce the wafer cost, and raising the open circuit voltage to obtain a better temperature coefficient. With the first approach, we have achieved the highest conversion efficiency values of 22.3%, confirmed by AIST, in a HIT solar cell. This cell has an open circuit voltage of 0.725 V, a short circuit current density of 38.9 mA/cm2 and a fill factor of 0.791, with a cell size of 100.5 cm2. The second approach is to use thinner Si wafers. The shortage of Si feedstock and the strong requirement of a lower sales price make it necessary for solar cell manufacturers to reduce their production cost. The wafer cost is an especially dominant factor in the production cost. In order to provide low-priced, high-quality solar cells, we are trying to use thinner wafers. We obtained a conversion efficiency of 21.4% (measured by Sanyo) for a HIT solar cell with a thickness of 85μm. Even better, there was absolutely no sagging in our HIT solar cell because of its symmetrical structure. The third approach is to raise the open circuit voltage. We obtained a remarkably higher Voc of 0.739 V with the thinner cell mentioned above because of its low surface recombination velocity. The high Voc results in good temperature properties, which allow it to generate a large amount of electricity at high temperatures.


2013 ◽  
Vol 724-725 ◽  
pp. 151-155
Author(s):  
Peng Wang ◽  
Xian Fang Gou ◽  
Wei Tao Fan ◽  
Chen Cai Sun

In order to improving the conversion efficiency of polycrystalline silicon solar cells, progressive SiNx thin films were deposited on the surface via Roth&Rau plasma-enhanced chemical vapor deposition method. The effects of progressive SiNx thin films, such as surface passivation, anti-reflection, and electrical performance were systematically investigated. Compared with monolayer films, progressive SiNx thin films have better anti-reflective properties in the wavelength range of 300-500 nm, resulting in improvement of the short wavelength absorption of the crystalline silicon solar cells. Moreover, the bottom of progressive SiNx thin films with high refractive index enhances the surface passivation. Thus, higher open-circuit voltage and fill factor could be obtained by this technique.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hwen-Fen Hong ◽  
Tsung-Shiew Huang ◽  
Wu-Yih Uen ◽  
Yen-Yeh Chen

We performed accelerated tests on sealed and nonsealed InGaP/InGaAs/Ge triple-junction (TJ) solar cells in a complex high temperature and high humidity environment and investigated the electrical properties over time. The degradation of energy conversion efficiency in nonsealed cells was found to be more serious than that in sealed cells. The short-circuit current (ISC), open-circuit voltage (VOC), and fill factor (FF) of sealed cells changed very slightly, though the conversion efficiency decreased 3.6% over 500 h of exposure. This decrease of conversion efficiency was suggested to be due to the deterioration of silicone encapsulant. TheISC,VOC, and FF of nonsealed cells decreased with increasing exposure time. By EL and SEM analysis, the root causes of degradation can be attributed to the damage and cracks near the edge of cells induced by the moisture ingress. It resulted in shunt paths that lead to a deterioration of the conversion efficiency of solar cell by increasing the leakage current, as well as decreasing open-circuit voltage and fill factor of nonsealed solar cells.


2011 ◽  
Vol 8 (2) ◽  
pp. 577-580 ◽  
Author(s):  
Baghdad Science Journal

The spectral response of the Si solar cell does not coincidence with the sun irradiance spectrum, so the efficiency of the Si solar cell is not high. To improve the Si solar cell one try to make use of most region of the sun spectrum by using dyes which absorb un useful wavelengths and radiate at useful region of spectrum (by stock shift). Fluorescence's dye is used as luminescent concentrator to increase the efficiency of the solar cell. The results show that the performance efficiency and out power for crystalline silicon solar cells are improved.


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