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Latest Updates
Below are the ten most recent resources that we have received. They are sorted according to posting date. Author information, full title, a brief description, and other details are also included.
These ten resources are also posted in the appropriate individual technology section.
| Post Date | 11/21/2008 |
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| Technologies | Cadmium Telluride, Copper Indium Diselenide |
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| Title | CHARACTERIZATION OF THE ELECTRONIC AND CHEMICAL STRUCTURE AT THIN FILM SOLAR CELL INTERFACES |
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| Link | (PDF 107 KB) Download Acrobat Reader. |
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| Author | C. Heske |
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| Description | This project is devoted to deriving the electronic structure of interfaces in Cu(In,Ga)(S,Se)2 and CdTe thin film solar cells. By using a unique combination of spectroscopic methods (photoelectron spectroscopy, inverse photoemission, and X-ray absorption and emission) a comprehensive picture of the electronic (i.e., band alignment in the valence and conduction band) as well as chemical structure is painted.
In February this year, the NREL group announced to have achieved a new world record effi-ciency (19.9%) for Cu(In,Ga)Se2 ?CIGSe? ? based thin-film solar cells (Ingrid Repins, Miguel A. Con-treras, Brian Egaas, Clay DeHart, John Scharf, Craig L. Perkins, Bobby To and Rommel Noufi, 19.9%-efficient ZnO/CdS/CuInGaSe2 Solar Cell with 81.2% Fill Factor, Prog. Photovolt. 16, 235 (2008).) This recent efficiency gain (compared to the former world record - 19.5%), is believed to be caused by a small ? but apparently significant ? change in the three-stage process. In comparison to the deposition process used earlier, the difference resulting in the recent world record CIGSe absorber was a termina-tion of the third (and thus last) stage without Ga and hence is considered to be ?In-terminated?.
In order to shed light on the expected different chemical surface structure, we investigated a sample from the world record absorber batch (M2992) by x-ray photoelectron spectroscopy (XPS) and xray excited Auger electron spectroscopy (XAES). Both techniques are very surface sensitive (information depth a few nm) and thus well suited to address questions of surface termination. In addition, we also characterized a CIGSe absorber (M2995) deliberately terminated with Ga for comparison.
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| Venue | University of Nevada, Las Vegas, subcontract XXL-5-44205-12, quarterly report |
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| Source | University of Nevada, Las Vegas |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 09/15/2008 |
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| Post Date | 11/19/2008 |
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| Technology | Cadmium Telluride |
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| Title | FABRICATION AND PHYSICS OF CDTE DEVICES BY SPUTTERING |
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| Link | (PDF 1.1 MB) Download Acrobat Reader. |
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| Authors | A. Compaan, R. W. Collins, V. G. Karpov, D. Giolando |
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| Description |
This report presents: 1) properties of phosphorus-doped CdTe films prepared by sputtering from pressed targets of CdTe and Cd3P2, 2) optimization studies on ultra-thin CdS/CdTe cells with efficiencies exceeding 10% for 0.5? |
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| Venue | University of Toledo, subcontract ZXL-5-44205-01, (CdTe), quarterly report |
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| Source | University of Toledo |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 08/2008 |
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| Post Date | 11/07/2008 |
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| Technology | Copper Indium Diselenide |
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| Title | HIGH THROUGHPUT, LOW TOXIC PROCESSING OF VERY HIGH EFFICIENCY CIGSS SOLAR CELLS |
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| Link | (PDF 602 KB) Download Acrobat Reader. |
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| Author | N. G. Dhere |
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| Description | Diifusion pump maintenance issues are reported.
Molybdenum has emerged as the dominant choice for the back contact layer to CIS and CIGSeS chalcopyrite thin film solar cells. It is essential to deposit stress-free and relatively inert Mo films in order to achieve well adherent and highly efficient CIGSeS absorber thin film solar cells. Molybdenum layer in compressive stress mode layer at top has lower sheet resistance as compared to molybdenum layer in tensile stress mode. This low sheet resistance is desirable for metallized back contact layer for solar cells. |
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| Venue | Florida Solar Energy Center, University of Central Florida, subcontract XXL-5-44205-08, quarterly report |
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| Source | FLorida Solar Energy Center |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 07/29/2008 |
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| Post Date | 11/04/2008 |
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| Technology | Amorphous and Thin Film Silicon |
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| Title | PROCESSING, MATERIALS, DEVICES AND DIAGNOSTICS FOR THIN FILM PHOTOVOLTAICS: FUNDAMENTAL AND MANUFACTURABILITY ISSUES |
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| Link | (PDF 1.3 MB) Download Acrobat Reader. |
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| Author | R. W. Birkmire |
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| Description | The report investigates passivation of x-Si wafers using PECVD deposited a-Si:H. An interdigitated back contact-silicon heterojunction cell with efficiency of 13.5% and FF of 77% is achieved with the narrower band gap i-layer. However, the Voc and Jsc is lower than the standard i-layer, which is due to insufficient surface passivation in the gap between the p- and n- strips. |
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| Venue | Institute of Energy Conversion, University of Delaware, subcontract ADJ-1-30630-12, monthly report |
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| Source | University of Delaware |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 08/19/2008 |
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| Post Date | 11/04/2008 |
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| Technology | Amorphous and Thin Film Silicon |
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| Title | FABRICATION AND CHARACTERIZATION OF ADVANCED TRIPLE-JUNCTION AMORPHOUS SILICON BASED SOLAR CELLS |
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| Link | (PDF 483 KB) Download Acrobat Reader. |
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| Authors | X. Deng, R. W. Collins |
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| Description |
High efficiency single junction n-i-p type a-Si:H solar cells were fabricated, with the intrinsic layers deposited at the edge of crystallinity. The stability tends to be better with increasing the RF-power, which improves the structure order in the i-layers. Solar cells with i-layers deposited just below the onset of crystallinity show a higher initial efficiency, while solar cells with i-layers deposited just above the onset of crystallinity show a better stability against light soaking. |
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| Venue | University of Toledo, subcontract ZXL-5-44205-06, quarterly report |
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| Source | University of Toledo |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 07/2008 |
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| Post Date | 11/04/2008 |
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| Technology | Cadmium Telluride |
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| Title | PROCESSING, MATERIALS, DEVICES AND DIAGNOSTICS FOR THIN FILM PHOTOVOLTAICS: FUNDAMENTAL AND MANUFACTURABILITY ISSUES |
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| Link | (PDF 439 KB) Download Acrobat Reader. |
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| Author | R. W. Birkmire |
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| Description | The report highlights progress for CdTe-based solar cells. During this period, effort was focused on two sub-tasks: (1) deposition and characterization of device structures with thin CdTe absorber layers and (2) deposition of CdTe/CdS/ITO onto a temporary supporting superstrate for transfer to a flexible polymer substrate. |
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| Venue | Instutute of Energy Conversion, University of Delaware, subcontract ADJ-1-30630-12, monthly report |
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| Source | University of Delaware |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 08/08/2008 |
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| Post Date | 11/04/2008 |
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| Technology | Amorphous and Thin Film Silicon |
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| Title | FABRICATION AND CHARACTERIZATION OF ADVANCED TRIPLE-JUNCTION AMORPHOUS SILICON BASED SOLAR CELLS |
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| Link | (PDF 1.2 MB) Download Acrobat Reader. |
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| Authors | X. Deng, R. W. Collins |
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| Description |
Nano-crystalline silicon solar cells on back-reflectors (BR) with ZnO films deposited at 120 ºC have low FF and low Jsc but high Voc. The reason of this phenomenon may be that the low temperature deposited ZnO films have less crystallinity, which causes the nano-crystalline silicon film to have more amorphous phase. But when the ZnO is deposited at high temperature (350 C), lots of ZnO crystalline rods show up, this can cause yield problems to solar cells. Based on the BR with ZnO deposited at 280 C, we have fabr icated a-Si:H/a-SiGe:H/nc-Si:H n-i-p triple junction solar cells with initial efficiency of 12.5%. |
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| Venue | University of Toledo, subcontract ZXL-5-44205-06, quarterly report |
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| Source | University of Toledo |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 07/2008 |
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| Post Date | 11/04/2008 |
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| Technology | Cadmium Telluride |
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| Title | PROCESSING, MATERIALS, DEVICES AND DIAGNOSTICS FOR THIN FILM PHOTOVOLTAICS: FUNDAMENTAL AND MANUFACTURING ISSUES |
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| Link | (PDF 365 KB) Download Acrobat Reader. |
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| Author | R. W. Birkmire |
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| Description |
The Effort was focused on two sub-tasks: (1) fabrication of devices with thin CdTe absorber layers, and (2) development of mechanically flexible CdTe cells by deposition onto a temporary support followed by transfer to a flexible polymer substrate.
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Best-cell J-V results for VT cells with thin CdTe absorber layers using vapor CdCl 2 treatment at 480ºC with 2 minute CdCl2
?m) |
V OC
(mV) |
J SC
(mA/cm 2) |
FF
(%) |
?
(%) |
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3.0 |
788 |
23.1 |
64.0 |
11.8 |
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1.5 |
807 |
23.8 |
56.8 |
10.9 |
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1.0 |
743 |
23.4 |
54.8 |
9.5 |
|
0.8 |
723 |
22.5 |
50.5 |
8.2 |
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| Venue | Institute of Energy Conversion, University of Delaware, subcontract ADJ-30630-12, monthly report |
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| Source | University of Delaware |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 08/27/2008 |
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| Post Date | 11/04/2008 |
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| Technology | Copper Indium Diselenide |
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| Title | PROCESSING, MATERIALS, DEVICES AND DIAGNOSTICS FOR THIN FILM PHOTOVOLTAICS: FUNDAMENTAL AND MANUFACTURABILITY ISSUES |
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| Link | (PDF 285 KB) Download Acrobat Reader. |
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| Author | R. W. Birkmire |
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| Description | We investigated processes to increase VOC in Cu(InGa)(SeS)2 solar cells using absorber layers formed by the reaction of precursors in H2Se / H2S which is typically low due to accumulation of Ga at the back of the reacted film. A two-step reaction of Cu-Ga-In precursors with partial reaction in H2Se at 400° ? 450°C followed by completion in H2S at 550°C has been used to form Cu(InGa)(SeS)2 films with uniform incorporation of the Ga.
Scribing tests for monolithic integration by mechanical and laser scribing have been started. Initial attempts in mechanically scribing the molybdenum (Mo) layer (P1 scribe) with a programmable x-y mechanical scribing system resulted in tearing of the Upilex. Double stick tape was then used to secure the Upilex giving much improved results. However, the resulting scribe showed only partial removal of the Mo layer. |
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| Venue | Institute of Energy Conversion, University of Delaware, subcontract ADJ-1-30630-12, monthly report |
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| Source | University of Delaware |
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| Document Type | Quarterly Report (Adobe Postscript file) |
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| Resource Date | 08/08/2008 |
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| Post Date | 10/29/2008 |
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| Technology | General Interest |
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| Title |   BEST PRODUCTION-LINE PV MODULE EFFICIENCY VALUES |
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| Link | (MS Word 55 KB) |
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| Author | B. Von Roedern |
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| Description | From Manufacturers? Websites, Compiled by Bolko von Roedern, September 2008 |
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| Venue | periodic update of this table by the author |
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| Source | National Renewable Energy Laboratory |
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| Document Type | Other Items (Word document) |
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| Resource Date | 09/2008 |
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