Deposition of Transparent Conductive Oxide Coatings on Thin Film Solar Cells using nAERO Deposition System by Beneq

Topics Covered

Overview
TCO Coatings for Thin Film Solar Cells
Properties of Transparent Conductive Oxide Coatings Produced by nAERO
nAERO Aerosol-Based Aerosol Coating
Purpose of Underlayer
Properties of Transparent Conductive Oxide Coating

Overview

Beneq Oy, based in Finland, is a supplier of equipment and coating technology for global markets. Beneq turns innovations into success by developing applications and equipment for cleantech and renewable energy fields, especially in glass, solar and emerging thin film markets. Coating applications include optics, barriers and passivation layers, as well as energy generation and conservation. Beneq also offers complete coating services. Beneq's coating applications are based on two enabling nanotechnology platforms: Atomic Layer Deposition (ALD) and aerosol coating (nHALO® and nAERO®).

TCO Coatings for Thin Film Solar Cells

With the surge of photovoltaics (PV) in the world today, solar cell manufacturers are looking for more economical coating solutions for their production lines. Beneq, with its own nAERO® aerosol-assisted pyrolytic deposition method, presents a technically superior and economical coating method for in-line and off-line coated products. nAERO is capable of producing low-haze and high-haze transparent conductive oxide (TCO) coatings, which allows the cell manufacturer to optimize the coating to suit his specific needs and thus maximize the efficiency of the thin film cell.

TCO coatings for thin film solar cells (a-Si, μc-Si and CdTe)

Properties of Transparent Conductive Oxide Coatings Produced by nAERO

A nAERO-produced TCO coating is a pyrolytic hard coating consisting of fluorine-doped tin oxide (SnO2:F). Coating parameters can easily be adjusted and optimized to yield best results for haze, conductivity or transmittance. Haze can be as low as < 1% or as high as 20%, including the range between the two extremes. nAERO TCO by Beneq is fully temperable and can be laser-scribed or wet-etched. In addition, the pyrolytic hard coating has very good adhesion to sealing materials.

nAERO Aerosol-Based Aerosol Coating

nAERO deposition is based on sub-micron sized droplets that are directed to the glass substrate. This enables a high growth rate and good material economics, with a raw material (precursor) yield of 20% or better.

Purpose of Underlayer

If needed, an underlayer consisting of SiOx, SiO2 or TiO2 can be added between the electrically active TCO layer and the glass substrate. This underlayer is produced in a process step prior to nAERO coating. The underlayer serves as a barrier layer against sodium diffusion and eliminates iridescence in reflected light.

Properties of Transparent Conductive Oxide Coating

The properties of transparent conductive oxide coating are listed in the table below:

Type Transparent conductive oxide (TCO)
Chemical composition SnO2:F (FTO)
Subgroup (based on haze) Low haze High haze
Haze, D65/10% 1 12(example)
Transmission2, average 400-1000 nm (%) > 83 > 83
Sheet resistance3 (Ω/□) 12 10
Emittance 0.15 0.15
Thickness (nm) 400 750
Uniformity, sheet resistance (deviation) < 2.0 (Ω/□)
Uniformity, transmission (deviation) < 1%
Temperable yes
  1. Transmission measured with index matching liquid CH3I (haze compensation) on 4 mm glass.
  2. Measured by 4-point method.

Source: Beneq

For more information on this source please visit Beneq

Date Added: Jan 14, 2011 | Updated: Jun 11, 2013
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