| Description |
1 online resource (30 pages) : color illustrations. |
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text txt rdacontent |
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computer c rdamedia |
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online resource cr rdacarrier |
| Series |
NREL/PR ; 5K00-80918 |
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NREL/PR ; 5K00-80918.
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| Note |
Slideshow presentation. |
| Funding |
DE-AC36-08GO28308 |
| Note |
Description based on online resource; title from PDF title page (NREL, viewed February 15, 2022). |
| Summary |
II-VI based thin-film photovoltaics (PV) have experienced substantial commercial success on a foundation of fast large-scale deposition and processing. This type of processing, regardless of material type, nearly always results in small grain (nm to several um diameters) polycrystalline material that, if not for effective grain boundary (GB) and defect passivation, would severely limit PV performance. In the case of CdTe based PV technology, the nearly ubiquitous CdCl2 treatment is used, in part, to passivate the polycrystalline p-type absorber even though Cl is known to (and used to) compensate p-type II-VI materials. Given that VOC is still the most limited performance metric and it can only be improved through higher p-type absorber concentrations, CdCl2 treatments may be holding the technology back. In this talk, we will discuss results related to a process by which small grain CdSeTe material is rapidly transformed into very large grain material (100-1000um diameters, Fig. 1a). This explosive recrystallization, which we have termed colossal grain growth (CGG), occurs by a Cl free process with thin films (<10um) deposited using the same fast deposition techniques the industry has relied on for more than a decade. Our modeling suggests that GB recombination becomes significantly less important at these grain sizes and thus may eliminate the need for a CdCl2 treatment. This result is complimented by previous results of epitaxial growth at high rates on single crystal seed layers. Thin CdSeTe CGG seed layers can be used for rapid epitaxy of CdTe to complete a standard device stack (Fig.1b). This is an optimistic view and the current limitations and challenges related to this process and these materials will also be discussed, including alloy and substrate roughness sensitivity, intragrain material quality, and complex defect chemistry. These challenges are not insignificant but overcoming them may enable a new structural paradigm for thin-film PV. |
| Subject |
Photovoltaic power generation -- United States.
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Thin films.
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Cadmium compounds.
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Polycrystals.
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Epitaxy -- United States.
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Cadmium Compounds |
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Conversion photovoltaïque -- États-Unis.
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Couches minces.
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Cadmium -- Composés.
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Polycristaux.
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Épitaxie -- États-Unis.
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Cadmium compounds. (OCoLC)fst00843794
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Epitaxy. (OCoLC)fst00914372
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Photovoltaic power generation. (OCoLC)fst01062167
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Polycrystals. (OCoLC)fst01070376
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Thin films. (OCoLC)fst01150018
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United States. (OCoLC)fst01204155 https://id.oclc.org/worldcat/entity/E39PBJtxgQXMWqmjMjjwXRHgrq
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| Indexed Term |
CdTe |
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fast epitaxy |
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grain growth |
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thin-film PV |
| Added Author |
National Renewable Energy Laboratory (U.S.), issuing body.
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United States. Department of Energy. Solar Energy Technologies Office, sponsoring body.
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| Standard No. |
1823440 OSTI ID |
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0000-0002-3811-2193 |
| Gpo Item No. |
0430-P-09 (online) |
| Sudoc No. |
E 9.22:NREL/PR-5 K 00-80918 |
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