Widespread adoption of solar cells is hindered by two problems: high manufacturing costs and the relatively low efficiency of converting sunlight into an electric current.

Yung Shin and co-workers, Purdue University, Indiana, USA, hope to reduce production costs and increase efficiency with a laser-based manufacturing method. The team uses an ultrafast laser to create the microchannels that connect individual solar panels into larger arrays. Current scribing methods, which use a stylus, are slow, expensive and produce imperfect channels, which retards solar cells’ performance.

Experiments for picosecond laser scribing were performed with different wavelengths and average powers. The laser was shown to form microchannels with precise depths (accurate within 0.1 μm tolerance) and sharp boundaries. The technique did not cause heat damage to the thin films of the solar cells and could be performed at high speeds (ms^-1) which is not possible with a mechanical scribe.

Image: Scanning electron microscope image of amicro-

channel created using an ultrafast-pulsing laser.

(C) Purdue University School of Mechanical Engineering/Yung Shin

• High Precision Scribing of Thin Film Solar Cells by a Picosecond Laser
  Y. C. Shin, G. Cheng, W. Hu, M. Y. Zhang, S. Lee,
  Proc. of the NSF Grantees Conference, Jan. 3-7, 2011, Atlanta, GA.