Solar cell performance and radiation resistance is improved by application of 1-mil thickness of Teflon FEP protective material. Cells produce 30 percent more power than similar cells with conventional Kapton covers

Anagnostou, E.

Bernatowicz, D. T.

Spakowski, A. E.

English

NASA Technical Reports Server

November 19 70
	
Brief 70-10584 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
-
Improved Cover for Cadmium Sulfide Solar Cells 
Cadmium sulfide film solar cells are fabricated with 
a cover to protect them from environmental condi-
tions of earth (humidity) and space (electron and 
proton radiation). Experiments have shown that thin 
film cadmium sulfide cells protected by a one-mu 
thickness of Teflon* FEP material will produce up 
to 30 percent more power than similar cells with con-
ventional Kapton* covers. 
Thin-film cadmium sulfide solar cells are presently 
constructed with a one-mil sheet of Kapton plastic as 
the top cover. This cover must not only transmit the 
solar energy in the wavelength region where the solar 
cell is sensitive, but also must be resistant to the 
hostile conditions of space. Kapton has been the best 
plastic material for this purpose because it does not 
degrade significantly when exposed to expected doses 
of ultraviolet light and electron and proton radiation. 
However, due to its structure, the transmission of 
usable solar energy is only about 66 percent. A one-
mil thickness of Teflon FEP material transmits approx-
imately 95 percent of the usable solar energy, and is also 
more resistant than Kapton to ultraviolet light and 
electron and proton radiation. 
The Teflon FEP material can be bonded directly or 
with suitable adhesives to the top surface of the cell. 
If adhesives are used, they must be resistant to the 
ultraviolet light passing through the transparent cover; 
otherwise, protective coatings must be used to elimi-
nate the effects of harmful radiation. 
Notes: 
1. The Teflon FEP can be used not only on the 
evaporated cadmium sulfide cells, but also on cad-
* DuPont's registered trademarks
mium sulfide and other semiconductor solar cells. 
made by a variety of methods, including spraying 
processes, pressed powder, and single crystals. 
2. The following documentation may be obtained from: 
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.65) 
Reference: 
NASA-TM-X-1905 (N69-40339), Transmis-
sion Effects on Plastic Films Irradiated with 
Ultraviolet Light, Electrons and Protons 
3. Technical questions may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Bróokpark Road 
Cleveland, Ohio 44135 
Reference: B70-10584 
Patent status: 
This invention is owned by NASA, and a patent
application has been filed. Royalty-free, nonexclusive 
licenses for its commercial use will be granted by 
NASA. Inquiries concerning license rights should be 
made to NASA, Code GP, Washington, D.C. 20546. 
Source: A. E. Spakowski, D. T. Bernatowicz and
E. Anagnostou
Lewis Research Center
(LEW-1 1003) 
Category 01,03 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned-rights.
https://ntrs.nasa.gov/search.jsp?R=19700000566 2020-03-17T00:38:33+00:00Z


Improved cover for cadmium sulfide solar cells

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