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Laser Structuring of Solar Cells

Mono and Polycrystalline and Thin Film Cells

Laser processing of silicon wafers and solar cells is mostly based on the direct, vapor-induced melt ejection by nanosecond laser pulses. This ablation method is especially characterized by high speed and precision.

Opening of Dielectric Layers

Opening of Dielectric Layers

A dielectric silicon nitride passivation layer is deposited onto the wafer in standard silicon solar cell concepts, in order to reduce reflectivity as well as surface recombination losses. Screen printing of a silver paste is the standard method for the metallization of the front side contacts. Major drawbacks of that classic design are the low aspect ratio of the metallization and the low conductivity, thus limiting cell efficiency. . Especially q-switched lasers with double frequencies are suited to open those passivation layers in grids or line patterns without significant heat input to the wafer substrate.  This enables new high-efficient solar cell concepts with highly doped areas located only below the contact fingers.

 

For these applications we recommend: PowerLine SL PV

Thin Film Solar Cells

Thin Film Solar Cells

Thin film solar cells are created by several coating and scribing processes. Lasers with best beam quality (TEM00) with very high repetition rates of up to 200 kHz are used for ablating 20 to 50 micron wide paths with scribing speeds of up to 2,000 mm/s without damaging the glass substrate or the layers underneath. This is the reason why Nd:Vanadat lasers with short ns-puls widths (max. 100 ns) are the standard laser type for this kind of application. The ideal wavelength for the various processes depends on the composition of the individual layers. Fundamental (1064 nm) and wavelengths with double frequency (532 nm) are commonly used in the production of a-Si, CIS and CdS/CdTe solar cells.

 

For these applications we recommend: Roll-to-Roll System, Lab System