The Room Temperature Wet Chemical Growth (RTWCG)

of Antireflection Coatings for Photovoltaic Cells

Photovoltaic Cells

The RTWCG passivating antireflection coatings with graded index of refraction are applied in one easy step on  finished (bare) photovoltaic cells. The RTWCG coatings grown on planar, textured and porous Si, as well as on CuInSe₂, and III-V substrates, show excellent uniformity irrespective of a photovoltaic cell's surface topography, crystal orientation, size, and shape.

Reflectivity of (a) a bare p-Si wafer and,

(b) a  RTWCG Si-O-C-N coated p-Si wafer.

As the reflectivity graph suggests, the SPECMAT proprietary RTWCG works well to lower a photovoltaic cell's reflectivity in the visible spectrum. This RTWCG Si-O-C-N coating has a reflectivity of below 1.8% from 600 nm to 950 nm and below 3.3% on the average from 400 nm to 1100 nm.

The RTWCG process for growing SiO-based coatings, once fully developed, should be an attractive alternative to conventional passivation / antireflection coating techniques for the Si, GaAs and other terrestrial and space photovoltaic cell manufacturers because the novel process:

• reduces photovoltaic cell fabrication costs by eliminating several concomitant photoresist, etching and surface passivation steps;

• has readily solderable contacts since the coating does not cover the metallization of the photovoltaic cell;

• is applicable to any surface irrespective of  surface topography, crystal orientation, size or shape;

• has high output due to large growth rates;

• reduces capital and materials costs.

Click on the following link for a general description of a photovoltaic cell..

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