Tracking advances in solar cell technology, I’ve stumbled across another landmark efficiency gain.
This one, obtained by switching from conventional screen printing to a non-contact aerosol jet printer, has upped efficiencies by 2 percent on thin-film solar cells.
Thin-film solar cells (TFSC) are defined as solar cells made by depositing one or more thin layers (nanometers to micrometers) of photovoltaic material on a substrate. These thin-film cells are classed as: amorphous silicon, cadmium telluride, copper indium gallium selenide (CIGS), polysilicon, dye-sensitized solar cells, or organic (plastic, or polymer) solar cells – the latter three still in development stages.
Printing is a deposition method, and the use of aerosol jet printing could raise the copper indium gallium selenide efficiency – already reported at 9.5 percent (with reports from NREL in excess of 19 percent) – to a value competitive with silicone-based solar at about half the cost to manufacture.
The advance, coming from the Fraunhofer Institute’s Solar Energy Systems in Germany, reports that using an Optomec printer enabled thinner strata deposition of metallic, semiconducting and insulating inks via nanoscale pigments developed by Applied Nanotech Inc. enabled efficiences in excess of 20 percent, as compared to previous figures of 16 to 18 percent.
Fraunhofer also used the printer to fabricate front-side metallization lines on otherwise conventional solar cells, which enabled it to shrink the metallization area and boost efficiency by reducing shading losses.
Screen-printed solar cells can be manufactured faster than ink-jet printing methods, and the Optomec’s 40-nozzle head can print a solar cell in under 3 seconds. What this means to you, the consumer, is a future of truly affordable solar. What it means to the environment is of inestimable value
Of course, waiting to save a few bucks doesn’t make a lot of sense in terms of the environment. News coming out of the United Nations Climate Change Conference in Poznan, Poland (December 5 to 12) indicates that climate change is not only upon us, but likely to reach that critical "tipping point" in as little as a decade.
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