Princeton Instruments (Trenton, NJ, USA) has produced an application note that details the use of photoluminescence (PL) imaging to inspect solar cells.
Recently, several groups in the US, Germany, Japan, Australia, and Singapore have begun exploring the advantages of using PL imaging in the near infrared (NIR) and shortwave infrared (SWIR) spectral regions to characterize multicrystalline silicon (mc-Si) solar cells.
Unlike electroluminescence (EL) imaging, which relies on the detection of relatively bright signals and can only be employed at the final stage of solar cell manufacturing, Princeton Instruments says that PL imaging can be implemented throughout the entire manufacturing process.
The ability to use this sensitive imaging technique during the early stages of the manufacturing process has significant ramifications, as PL images of ingots, bricks, and as-cut wafers can be predictive of final solar cell efficiency.
More information is available here.
Interested in solar cell inspection? Here are some recent articles on the subject from Vision Systems Design that you might also find of interest.
1. Linescan cameras target thin-film solar panel production
Basler has integrated three systems at solar panel manufacturer Sunfilm (Grossroehrsdorf, Germany) to perform front glass/TCO inspection (FGI), lamination inspection (LAM), and coating vapor deposition (CVD) inspection.
2. Spectral imaging aids PV production
A joint team from the Department of Electrical and Computer Engineering at the National University of Singapore and the Institute of Applied Physics at the University of Karlsruhe in Germany has demonstrated a novel imaging technique to improve the efficiencies of the solar cells as well as their production yields.
3. Smart camera inspects solar wafer codes
FiberVision (Würselen, Germany) has developed a system that can read the barcodes on the sides of solar wafers at rates up to 3600 wafers/hour.
4. Machine vision speeds edge isolation in solar cells
Eckelmann (Wiesbaden, Germany) has developed a vision system to measure the geometric properties of solar wafers.
5. Software compensates for lighting nonuniformity in solar cell inspection
Owens Design (Fremont, CA, USA) has developed a solar cell inspection system to check part distance measurements and their orientation, features, and blemishes.
-- Dave Wilson, Senior Editor, Vision Systems Design