System locates high- and low-output regions in cadmium sulfide thin film photovoltaic cells. High resolution photograph shows conversion efficiency of each scanned area. X-Y recorder fed by amplified signal from solar cell also produces power contour map. Photo and map reveal high- and low-conversion-efficiency regions

Evans, J. C., Jr.

English

NASA Technical Reports Server

July 1971	 Brief 71-10223 
NASA TECH BRIEF 
Lewis Research Center	
_CV 
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 program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Solar Cell Power Scanner 
An electro-optical system has been developed for 
scanning the power output of solar cells. Although 
applicable to a wide range of light-sensitive planar 
semiconductor devices, the system has mainly been 
M Scan Readout I 1 \CRO 
CR0 Voltage 
Amplifiers ______	 - 
used to locate high- and low-output regions in cad-
mium sulfide thin film photovoltaic cells. 
The apparatus (Fig. 1) consists of two cathode 
ray oscilloscopes (CRO's), raster-scanned in syn-
chronization. The moving light spot on one CR0 
scans over the active area of a solar cell attached 
to the CR0 tube face. The microvolt output 
from the solar cell is amplified to modulate the 
intensity of the beam on the second CR0, which is 
used for readout. 
In practice, a solar cell is scanned using a con-
ventional TV raster scan. The spot size is held as 
small as possible consistent with the output of an 
adequate signal. During a complete solar cell scan, 
the shutter of the camera is left open. A high-
resolution photograph showing the conversion effi-
ciency of each scanned area is obtained. 
A power contour map (Fig. 2) may also be pro-
duced by a X-Y recorder fed by the amplified signal
from the solar cell. The photo and map reveal high-
and low-conversion-efficiency regions, which may 
subsequently be analyzed. 
Figure 2. Power Contour Map of Solar Cell 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B71-10223 
Patent status: 
No patent action is contemplated by NASA. 
Source: J. C. Evans, Jr.
Lewis Research Center

(LE W-1 1280) 
—	 Solar	 Camera Lens 
Cell
Figure 1. Schematic of Apparatus
Category 02 
This documetct 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.
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Solar cell power scanner

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