Improving the Conversion Efficiency and Decreasing the Thickness of the HIT Solar Cell

2009 ◽  
Vol 1210 ◽  
Author(s):  
Hirotada Inoue ◽  
Yasufumi Tsunomura ◽  
Daisuke Fujishima ◽  
Ayumu Yano ◽  
Shigeharu Taira ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Conversion Efficiency ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
High Conversion ◽  
Surface Recombination Velocity ◽  
Substrate Thickness ◽  
High Conversion Efficiency

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 (Heterojunction with Intrinsic Thin-layer) solar cell is an amorphous silicon (a-Si) / c-Si heterojunction solar cell that exhibits the potential to make this possible. Our recent R&D activities have achieved the world’s highest conversion efficiency of 23.0% with a practical sized (100.4 cm2) HIT solar cell, by improving the quality of the surface passivation, reducing the optical absorption loss and reducing the resistance loss. We have also developed a HIT solar cell with a thickness of only 98 mm, which has a very high conversion efficiency of 22.8%. This value is comparable to that of the conventional HIT solar cell, which has a thickness of more than 200 mm. Moreover, we have fabricated HIT solar cells using thinner c-Si substrates (96 to 58 μm), and found that the Voc increased with decreases in the substrate thickness, and reached an extremely high value of 0.745 V with a thickness of only 58 μm. This indicates that the surface recombination velocity of the HIT structure is extremely low due to the excellent passivation of the c-Si surface.

a-SiGe:H Alloy and its Application to Tandem-Type Solar Cell

1986 ◽  
Vol 70 ◽  
Author(s):  
Y. Yukimoto ◽  
M. Aiga
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Amorphous Silicon ◽  
Cell Size ◽  
Conversion Efficiency ◽  
High Conversion ◽  
High Conversion Efficiency ◽  
Silicon Alloy

ABSTRACTAmorphous SiGe:H alloy is the key material in achieving high conversion efficiency with tandem-type amorphous silicon alloy solar cells. Status and issues for this key material are discussed, and efforts made to irprove it are reviewed to obtain directions for higher quality a-SiGe:H alloys. An application of the improved alloy to tandem-type solar cell to achieve 9.6% efficiency for the cell size of 100 cm2 is reported.

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 ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Conversion Efficiency ◽  
Open Circuit Voltage ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Open Circuit ◽  
Silicon Solar Cells ◽  
Si Substrate ◽  
Symmetrical Structure

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.

Aluminum Oxide Passivation Layer for Crystalline Silicon Solar Cells Deposited by Mist CVD in Open-Air Atmosphere

2014 ◽  
Vol 1647 ◽  
Author(s):  
Toshiyuki Kawaharamura ◽  
Takayuki Uchida ◽  
Kenji Shibayama ◽  
Shizuo Fujita ◽  
Takahiro Hiramatsu ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
High Performance ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Breakdown Field ◽  
Air Atmosphere ◽  
Si Solar Cells

ABSTRACTThe surface passivation of Si wafer by AlOx thin films grown by mist CVD in an open-air atmosphere was studied with a view to improving the effect of high-performance c-Si solar cells. In AlOx thin film grown at a temperature above 400°C by mist CVD, the OH bonding did not remain in the film and the breakdown field (EBD) was over 6 MV/cm. In Si wafers passivated by AlOx thin films grown by mist CVD at growth temperature above 400°C, the negative fixed charge density (Qf) at the interface was higher than 1012 cm-2 and the surface recombination velocity (Seff) was 44.4 cm/s. These results show that mist CVD, which is fundamentally an environmentally friendly technique, may be suitable for the fabrication of a passivation film on Si surfaces designed to improve the effect of high-performance c-Si solar cells.

scholarly journals Crystalline Silicon Solar Cells with Thin Silicon Passivation Film Deposited prior to Phosphorous Diffusion

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Ching-Tao Li ◽  
Fangchi Hsieh ◽  
Shi Yan ◽  
Cuifeng Wan ◽  
Yakun Liu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Front Surface ◽  
Phosphorus Diffusion ◽  
Crystalline Silicon Solar Cells ◽  
Performance Improvements ◽  
Passivation Film

We demonstrate the performance improvement of p-type single-crystalline silicon (sc-Si) solar cells resulting from front surface passivation by a thin amorphous silicon (a-Si) film deposited prior to phosphorus diffusion. The conversion efficiency was improved for the sample with an a-Si film of ~5 nm thickness deposited on the front surface prior to high-temperature phosphorus diffusion, with respect to the samples with an a-Si film deposited on the front surface after phosphorus diffusion. The improvement in conversion efficiency is 0.4% absolute with respect to a-Si film passivated cells, that is, the cells with an a-Si film deposited on the front surface after phosphorus diffusion. The new technique provided a 0.5% improvement in conversion efficiency compared to the cells without a-Si passivation. Such performance improvements result from reduced surface recombination as well as lowered contact resistance, the latter of which induces a high fill factor of the solar cell.

scholarly journals Numerical Simulation Analysis of Ag Crystallite Effects on Interface of Front Metal and Silicon in the PERC Solar Cell

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 592
Author(s):  
Myeong Sang Jeong ◽  
Yonghwan Lee ◽  
Ka-Hyun Kim ◽  
Sungjin Choi ◽  
Min Gu Kang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Surface Recombination ◽  
Open Circuit ◽  
Surface Recombination Velocity ◽  
Metal Interface ◽  
Ag Crystallites ◽  
Recombination Velocity

In the fabrication of crystalline silicon solar cells, the contact properties between the front metal electrode and silicon are one of the most important parameters for achieving high-efficiency, as it is an integral element in the formation of solar cell electrodes. This entails an increase in the surface recombination velocity and a drop in the open-circuit voltage of the solar cell; hence, controlling the recombination velocity at the metal-silicon interface becomes a critical factor in the process. In this study, the distribution of Ag crystallites formed on the silicon-metal interface, the surface recombination velocity in the silicon-metal interface and the resulting changes in the performance of the Passivated Emitter and Rear Contact (PERC) solar cells were analyzed by controlling the firing temperature. The Ag crystallite distribution gradually increased corresponding to a firing temperature increase from 850 ∘C to 950 ∘C. The surface recombination velocity at the silicon-metal interface increased from 353 to 599 cm/s and the open-circuit voltage of the PERC solar cell decreased from 659.7 to 647 mV. Technology Computer-Aided Design (TCAD) simulation was used for detailed analysis on the effect of the surface recombination velocity at the silicon-metal interface on the PERC solar cell performance. Simulations showed that the increase in the distribution of Ag crystallites and surface recombination velocity at the silicon-metal interface played an important role in the decrease of open-circuit voltage of the PERC solar cell at temperatures of 850–900 ∘C, whereas the damage caused by the emitter over fire was determined as the main cause of the voltage drop at 950 ∘C. These results are expected to serve as a steppingstone for further research on improvement in the silicon-metal interface properties of silicon-based solar cells and investigation on high-efficiency solar cells.

scholarly journals Surface passivation and optical characterization of Al2O3/a-SiCx stacks on c-Si substrates

2013 ◽  
Vol 4 ◽  
pp. 726-731 ◽  
Author(s):  
Gema López ◽  
Pablo R Ortega ◽  
Cristóbal Voz ◽  
Isidro Martín ◽  
Mónica Colina ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Surface Passivation ◽  
Crystalline Silicon ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Optical Characterization ◽  
Surface Recombination Velocity ◽  
Carrier Injection ◽  
Si Substrates

The aim of this work is to study the surface passivation of aluminum oxide/amorphous silicon carbide (Al2O3/a-SiCx) stacks on both p-type and n-type crystalline silicon (c-Si) substrates as well as the optical characterization of these stacks. Al2O3 films of different thicknesses were deposited by thermal atomic layer deposition (ALD) at 200 °C and were complemented with a layer of a-SiCx deposited by plasma-enhanced chemical vapor deposition (PECVD) to form anti-reflection coating (ARC) stacks with a total thickness of 75 nm. A comparative study has been carried out on polished and randomly textured wafers. We have experimentally determined the optimum thickness of the stack for photovoltaic applications by minimizing the reflection losses over a wide wavelength range (300–1200 nm) without compromising the outstanding passivation properties of the Al2O3 films. The upper limit of the surface recombination velocity (S eff,max) was evaluated at a carrier injection level corresponding to 1-sun illumination, which led to values below 10 cm/s. Reflectance values below 2% were measured on textured samples over the wavelength range of 450–1000 nm.

Micro- and Nanotextured Silicon for Antireflective Coatings of Solar Cells

2016 ◽  
Vol 39 ◽  
pp. 89-95 ◽  
Author(s):  
Anatoly Druzhinin ◽  
Valery Yerokhov ◽  
Stepan Nichkalo ◽  
Yevhen Berezhanskyi
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
Silicon Substrate ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Silicon Surfaces ◽  
Antireflective Coatings ◽  
High Conversion Efficiency ◽  
Industrial Use

The paper deals with obtaining of textured silicon surfaces by chemical etching. As a result of experiments based on the modification and optimization of obtaining a textured silicon, several methods of chemical texturing of the crystalline silicon surface were developed. It was shown that modified isotropic and anisotropic etching methods are applicable to create a microrelief on the surface of silicon substrate. These methods in addition to their high conversion efficiency can be used for both mono- and multicrystalline silicon which would ensure their industrial use.

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