PORTLAND, Ore. Germany's Fraunhofer Institute is reporting a 2 percent efficiency gain for silicon solar cells by switching from conventional screen printing to a non-contact aerosol jet printer.
Using a printer made by Optomec (Albuquerque, N.M.), Fraunhofer Institute's Solar Energy Systems (Freiburg, Germany), thinner silicon wafers were produced, reducing the cost of making solar cells. The institute said Optomec's aerosol printer delivered 20.3 percent efficiency for solar cells that previously achieved 16 to 18 percent efficiency.
Optomec's printer works like a conventional ink-jet printer, but utilizes nanoscale inks developed by Applied Nanotech Inc. (Austin, Texas) and other nanoparticle ink providers. The aerosol jet printer transferred metallic, semiconducting and insulating inks onto a shaped substrate to reproduce electronic circuitry on silicon wafers used for solar cells. It can also be used to make inexpensive, flexible polymer films for RFID tags and other electronic applications.
Fraunhofer also said it used the printer to fabricate front-side metallization lines on otherwise conventional solar cells, thereby shrinking the metallization area and boosting efficiency by reducing shading losses. The aerosol jet printed front-side grids using light-induced plating with sub-45-micron line widths to achieve plated contacts that were 43 percent of the grid's geometrical width.
Screen-printed solar cells can be produced faster than using ink-jet printing processes. Optomec claims its 40-nozzle aerosol jet deposition head can print a solar cell in less than 3 seconds using thinner photovoltaic wafers, offsetting slower printing time by reducing material costs.