Researchers in Germany Create Cost-effective Solar Cell Deposition Method

• Scientists led by the Technical University of Ilmenau in Germany assert that if silicon dioxide (SiO2) films are transferred at space temperature without intricate vacuum systems, they can be an excellent, cost-effective prospect for usage in commercial c-Si solar cell assembly line. SiO2 deposition is utilized as a passivation layer or a protective layer in different kinds of silicon PV cells.

In a paper entitled 'Application of Hydrosilane-free Atmospheric Pressure Chemical Vapor Deposition of SiOx Films in the Manufacture of Crystalline Silicon Solar Cells', released last year in the journal Thin Solid Films, the researchers developed a new process for the deposition of silicon dioxide layers during cell production. Without the need for high pressure, flammable gases, or vacuum problems, the process might bring about set you back reductions for cell manufacturers, provided it can be established and also used in a large-scale manufacturing setup.

" In this work we offer SiOx films deposited in cost-effective laboratory scale three-dimensional printed atmospheric pressure chemical vapor deposition arrangement," the researchers state. The group keeps in mind that plasma-enhanced chemical vapor deposition (PECVD) is the most common procedure utilized with this material, but requires both heats and a vacuum.

The high quality of the deposited films was checked out as to their honesty, conformity with various surfaces, as well as post-treatment durability such as security versus etchants as well as annealing. Several applications of the SiOx film prepared with the atmospheric pressure chemical vapor deposition (APCVD) were reviewed.

In one application, the APCVD SiOx was utilized to properly promote single-side texturing of Float Zone and Czochralski Si wafers by layer just one side with SiOx as well as ultimately annealing before texturing in an alkaline aqueous option. One more application was to manipulate the APCVD SiOx as a layering mask for silicon heterojunction solar cells.

Two processing alternatives before the oxide-film deposition were explored: i) application of an Ag seed-layer, which promotes succeeding electroplating, and ii) printing of an organic grid, which, after stripping, produces openings in the SiOx that facilitate electroplating of the solar cell's electrode on the underlying transparent performing oxide.

In a various application, the APCVD SiOx films functioned as defense versus parasitic plating on the front side of passivated emitter and rear solar cells. The deposited films were characterised by ellipsometry, hemispherical reflectance dimensions, scanning electron microscopy, power dispersive X-ray spectroscopy and also optical microscopy.

The researchers end, "The recently established APCVD arrangement offers an easy and tailorable approach for the deposition of SiO2 films on practically every substrate material at area temperature level," including, "Due to the used non-flammable as well as inexpensive gases, the prices of the deposition equipment and of the procedures are low. The here and now straightforward APCVD SiO2 process can find a number of applications in photovoltaics."

This work is still taking place to bring the procedure to a commercial scale, as part of a collaboration with Hannover-based finishes business Alethia, which is currently readied to run until May 2022. The paper was authored by Esmail Issa, Henning Nagel, Jonas Bartsch, Markus Glatthaar as well as Edda Rädlein.