Solar Power World

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A manufacturer of industrial inkjet printheads will bring a non-contact version to the solar market. Equipment manufacturer Trident Solar has partnered with Alpha — a Cookson Electronics company that produces materials used in electronic assembly processes and solar energy collection — to offer photovoltaic cell manufacturers direct pattern printing and etching. Trident’s inert 256Jet-S inkjet printhead works with Alpha’s line of jettable solar materials, including both p and n dopants, conductive-metallic inks with dielectric silver, and etchants. Together, these have potential to increase cell efficiency up to 1% when compared to the use of traditional screen printing methods.

Trident Solar says the additive inkjet process lets manufacturers print exactly the amount of material they need exactly where they need it, saving significant time, expense, and waste.

“Whereas other inkjet companies simply adapt existing printheads for the photovoltaic market, Trident Solar has developed a repairable, inert, stainless steel printhead specifically to provide reliable performance with the aggressive materials used in solar technologies,” says Mike Marczi, director of business development at Alpha. “Trident printheads have ten times the life expectancy of other inkjet printheads when printing acid and alkaline solutions for solar applications, and are well suited for jetting Alpha’s etchant inks.”

The printhead and ink allow etching narrow-feature line widths as small as 100 microns with SiNx, a-Si, or c-Si. In addition, a technology-development roadmap has targeted production of etched features as narrow as 40 microns. The inkjet’s capability to etch away SiNx reflective material on photovoltaic cells in the valleys and peaks of the silicon active layer ensure minimal resistance of the contact to the silicon.

The inkjet can also use conductive metal inks (such as silver ink) to produce contact lines with a thickness, 1/2 to 1/3 finer than that possible with silver paste and rotary-screen printing.  The reduced contact-line width reduces shadowing on the active layer for increased cell efficiency. The process can also produce lines or holes without the damage and defects associated with lasers. Digital printing is non-contact so it eliminates breakage and resulting scrap.

Trident Solar www.trident-itw.com

Alpha www.cooksonelectronics.com