Efficient light trapping structure in thin film silicon solar cells
Thin film silicon solar cells are believed to be promising candidates for continuing cost reduction in photovoltaic panels because silicon usage could be greatly reduced. Since silicon is an indirect bandgap semiconductor, its absorption coefficient is low for photons in the wavelength ranges betwee...
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| Format: | Article |
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Institute of Electrical and Electronics Engineers (IEEE)
2013
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| Online Access: | http://hdl.handle.net/1721.1/79773 https://orcid.org/0000-0002-3913-6189 |
| _version_ | 1826193847212834816 |
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| author | Sheng, Xing Liu, Jifeng Kozinsky, Inna Michel, Jurgen Kimerling, Lionel C. Agarwal, Anuradha Murthy |
| author2 | MIT Materials Research Laboratory |
| author_facet | MIT Materials Research Laboratory Sheng, Xing Liu, Jifeng Kozinsky, Inna Michel, Jurgen Kimerling, Lionel C. Agarwal, Anuradha Murthy |
| author_sort | Sheng, Xing |
| collection | MIT |
| description | Thin film silicon solar cells are believed to be promising candidates for continuing cost reduction in photovoltaic panels because silicon usage could be greatly reduced. Since silicon is an indirect bandgap semiconductor, its absorption coefficient is low for photons in the wavelength ranges between 600nm and 1100nm. For high efficiency thin film modules, effective light trapping is essential. Traditional schemes such as textured transparent conductive oxide (TCO) and metal reflector have several disadvantages such as enhanced surface recombination, parasitic losses at the TCO/metal interface, and the lack of ability to control and optimize the textured surface. We have previously proposed to employ a light trapping structure, which combines a self-assembled submicron grating and a distributed Bragg reflector (DBR) on the backside of thin film silicon solar cells. The DBR works as a one-dimensional photonic crystal to obtain almost 100% reflectivity. The grating scatters the incident light into oblique angles to significantly enhance the optical path length. Numerical calculations predict that by optimizing the feature sizes of the grating and DBR, up to 31% relative efficiency increase can be obtained, compared to the bare thin film Si. By using self-assembly, the organized grating structure can be formed spontaneously at a much lower cost. Current-voltage relations and quantum efficiency measurements were taken to verify the performance of our designed back structure. In the wavelength range of 600-900nm, photon absorption is greatly enhanced. As a result, more than 20% relative efficiency enhancement is achieved for 1.5um thin film silicon cells. These numerical and experimental results show that a light trapping design can be low-cost and increase efficiencies for high performance thin film Si solar cells. |
| first_indexed | 2024-09-23T09:46:19Z |
| format | Article |
| id | mit-1721.1/79773 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:46:19Z |
| publishDate | 2013 |
| publisher | Institute of Electrical and Electronics Engineers (IEEE) |
| record_format | dspace |
| spelling | mit-1721.1/797732022-09-30T16:42:07Z Efficient light trapping structure in thin film silicon solar cells Sheng, Xing Liu, Jifeng Kozinsky, Inna Michel, Jurgen Kimerling, Lionel C. Agarwal, Anuradha Murthy MIT Materials Research Laboratory Massachusetts Institute of Technology. Department of Materials Science and Engineering Sheng, Xing Liu, Jifeng Agarwal, Anuradha Murthy Michel, Jurgen Kimerling, Lionel C. Thin film silicon solar cells are believed to be promising candidates for continuing cost reduction in photovoltaic panels because silicon usage could be greatly reduced. Since silicon is an indirect bandgap semiconductor, its absorption coefficient is low for photons in the wavelength ranges between 600nm and 1100nm. For high efficiency thin film modules, effective light trapping is essential. Traditional schemes such as textured transparent conductive oxide (TCO) and metal reflector have several disadvantages such as enhanced surface recombination, parasitic losses at the TCO/metal interface, and the lack of ability to control and optimize the textured surface. We have previously proposed to employ a light trapping structure, which combines a self-assembled submicron grating and a distributed Bragg reflector (DBR) on the backside of thin film silicon solar cells. The DBR works as a one-dimensional photonic crystal to obtain almost 100% reflectivity. The grating scatters the incident light into oblique angles to significantly enhance the optical path length. Numerical calculations predict that by optimizing the feature sizes of the grating and DBR, up to 31% relative efficiency increase can be obtained, compared to the bare thin film Si. By using self-assembly, the organized grating structure can be formed spontaneously at a much lower cost. Current-voltage relations and quantum efficiency measurements were taken to verify the performance of our designed back structure. In the wavelength range of 600-900nm, photon absorption is greatly enhanced. As a result, more than 20% relative efficiency enhancement is achieved for 1.5um thin film silicon cells. These numerical and experimental results show that a light trapping design can be low-cost and increase efficiencies for high performance thin film Si solar cells. Robert Bosch GmbH Massachusetts Institute of Technology. Energy Initiative 2013-08-05T14:10:57Z 2013-08-05T14:10:57Z 2010-06 Article http://purl.org/eprint/type/ConferencePaper 978-1-4244-5890-5 0160-8371 http://hdl.handle.net/1721.1/79773 Sheng, Xing, Jifeng Liu, Inna Kozinsky, Anuradha M. Agarwal, Jurgen Michel, and Lionel C. Kimerling. “Efficient light trapping structure in thin film silicon solar cells.” In 2010 35th IEEE Photovoltaic Specialists Conference, 001575-001576. © Copyright 2010 IEEE https://orcid.org/0000-0002-3913-6189 en_US http://dx.doi.org/10.1109/PVSC.2010.5617124 Proceedings of the Photovoltaic Specialists Conference (PVSC), 2010 35th IEEE Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Electrical and Electronics Engineers (IEEE) IEEE |
| spellingShingle | Sheng, Xing Liu, Jifeng Kozinsky, Inna Michel, Jurgen Kimerling, Lionel C. Agarwal, Anuradha Murthy Efficient light trapping structure in thin film silicon solar cells |
| title | Efficient light trapping structure in thin film silicon solar cells |
| title_full | Efficient light trapping structure in thin film silicon solar cells |
| title_fullStr | Efficient light trapping structure in thin film silicon solar cells |
| title_full_unstemmed | Efficient light trapping structure in thin film silicon solar cells |
| title_short | Efficient light trapping structure in thin film silicon solar cells |
| title_sort | efficient light trapping structure in thin film silicon solar cells |
| url | http://hdl.handle.net/1721.1/79773 https://orcid.org/0000-0002-3913-6189 |
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