Who is Innovalight?


If you are like me and wonder what Innovalight really does, this posting should help.

At first glance, I erroneously thought they made their own entire solar cell out of silicon nanocrystals.  Images of solar cells with the captions "Ultra Thin" and ambiguous PR postings on their site such as "Innovalight Establishes New Record with Silicon Ink Solar Cells" gave me that impression.  Based on a conversation  with an unnamed solar cell expert, I learned that their nanocrystal technology merely simplifies the doping process for selective emitters and bases.  This is not to say their technology is insignificant, please bear in mind.

In a solar cell, selective emitter and base pn junctions are required for high efficiencies.  These pn junctions perform best when they are locally created across the plane of the wafer.  The conventional method of forming these junctions is to spray phosphorous or boron containing solution onto the target point, and then heat it in an oven to diffuse the dopant atoms into the bulk crystal of the wafer.  For point contact cells such as those from SunPower, photolithography may be necessary to achieve the locally diffused geometry.

Innovalight has developed a printable ink consisting of silicon nanocrystals to achieve this task in a more cost-effective matter.  Through printing, photolithography may be avoided.  By using pre-doped nanocrystals, the junctions formed after the annealing process may be precisely controlled.  They don't make the entire cell; they just have technology for one step of the process, the doping.  This explains why they are seeking to team up with solar cell manufacturers, such as JA Solar.  For more on their collaboration with JA Solar, see this posting from their site.

Some background on the company -- Innovalight started out making the nanocrystal ink for inexpensive, large area lighting.  Hence, the word light in their company name.  As that idea didn't go well, they realized that they could use their technology for solar cell applications instead.  Hopefully this posting will make the meaning of such process flow diagrams, such as the one shown below, more understandable.

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