NREL is a national laboratory of the U.S. Department of Energy, Office of Energy 

Efficiency & Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.

Contract No. DE-AC36-08GO28308

Development of Thin Film Silicon 

Solar Cell Using Inkjet Printed 

Silicon and Other Inkjet 

Processes

Cooperative Research and Development 

Final Report

CRADA Number: CRD-07-260

NREL Technical Contact: Bhushan Sopori

CRADA Report

NREL/TP-7A10-53846

April 2012
NOTICE

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In accordance with Requirements set forth in Article XI.A(3) of the CRADA document, this document is 

the final CRADA report, including a list of Subject Inventions, to be forwarded to the Office of Science

and Technical Information as part of the commitment to the public to demonstrate results of federally 

funded research.

Cooperative Research and Development Final Report

CRADA number: CRD-07-260 (WR91)

CRADA Title: Development of Thin Film Silicon Solar Cell Using Inkjet Printed Silicon and Other Inkjet 

Processes

Parties to the Agreement: Silexos

Joint Work Statement Funding Table showing DOE commitment:

Estimated Costs NREL 

Shared Resources

Year 1 $ 00.00

Year 2 $ 80,000.00

Year 3 $ 00.00

TOTALS $ 80,000.00

Abstract of CRADA work:

The cost of silicon photovoltaics (Si-PV) can be greatly lowered by developing thin-film crystalline Si solar 

cells on glass or an equally lower cost substrate. Typically, Si film is deposited by thermal evaporation, 

plasma enhanced chemical vapor deposition, and sputtering. NREL and Silexos have worked under a 

CRADA to develop technology to make very low cost solar cells using liquid organic precursors. 

Typically, cyclopentasilane (CPS) is deposited on a glass substrate and then converted into an a-Si film by 

UV polymerization followed by low-temperature optical process that crystallizes the amorphous layer. 

This technique promises to be a very low cost approach for making a Si film.

Summary of Research Results:

Because CPS is a pyrophoric material, this work has to be done is a highly controlled ambient of very low 

oxygen and moisture, in a glove box. CPS is a thin monomer that does not like to stick to glass and, even 

when it does, it is extremely difficult to make 1 μm or thicker films. We were able to overcome these 

difficulties and we were able to make thick films of crystallized silicon. We also studied methods to 

make heterojunctions devices.
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A number of large-area, thick films were prepared by applying principles interface engineering to study 

effect of interface roughness on the adhesion of the amorphous silicon film. The films ranged between 

1 μm and 6 μm in thickness. We were also able to convert these thick a-Si films into small grain 

crystalline films. We also successfully prepared ZnO:Al/(n)Si heterojunctions. These devices have shown 

record high open circuit voltages. Fully finished cells were not made.

Subject Inventions listing:

ROI-10-24: Thin Film Heterojunction Silicon Solar Cells

Report Date: 2/21/12 Responsible Technical Contact at Alliance/NREL: Bhushan Sopori

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