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The revolution becomes the institution: Innovalight CEO Conrad Burke on nanosilicon ink, selective emitters and the commercialization of process improvements

Conrad Burke
Conrad Burke

Conrad Burke is president and CEO of Innovalight, a company that has developed a portfolio of patented technologies and materials that allow current cell manufacturing companies to cost effectively produce solar cells with higher conversion efficiencies. Among these technologies, the company's Cougar platform is a new, low cost cell design enabled by Innovalight Silicon Ink that allows cell manufacturers to increase the efficiencies of crystalline silicon solar cells.

Prior to Innovalight, Mr. Burke was senior vice president of worldwide sales and marketing for Bookham Inc. Before Bookham, he was a venture partner at Sevin Rosen Funds, a leading US-based venture capital firm. His career has spanned research and development, product management, marketing, sales, general management and operations in major global organizations including NEC, AT&T, Lucent Technologies and Agere Systems.

Mr. Burke was also the first executive hire at OMM Inc., a venture backed startup based in San Diego, California focused on developing MEMS based optical switching systems. He has deep international experience having lived in and run major operations in Germany, UK and Japan.

Conrad Burke represented Innovalight at the World Economic Forum’s Annual Meeting in Davos, Switzerland in 2006 to receive the Technology Pioneer Award for Environmental and Energy Technologies. In October 2010, Conrad received the 2010 Ernst & Young Emerging Entrepreneur of the Year Award.


Solar Server: Can you give us a brief overview of Innovalight's cell efficiency improvement technologies, how they were developed, and what they offer?

Conrad Burke: Innovalight has developed on cells a nanocrystalline-based silicon ink. This is a liquid form of silicon that has unique properties that have an unusual effect when applied to a silicon wafer. And by doing so, we exploit that to improve the conversion efficiencies in solar cell manufacturing.

So what we do is we sell our silicon ink. We also license a process in conjunction with that silicon ink to solar cell manufacturing companies. And what this allows solar cell manufacturing companies to do is to take their existing manufacturing platform, or factory if you will, and it allows them to add one additional step on the front-end process whereby a solar cell is converted into a higher-efficiency solar cell using our process.

So one step of that is through a manufacturing line, and it approves the baseline efficiency by an absolute 1%, it improves the conversion efficiency, so a 17% cell becomes an 18% cell, an 18% cell becomes a 19% cell, just to give you an example.


Solar Server: Can you describe how the different components of Innovalight's silicon ink process work together, specifically the silicon nanoparticle ink and the diffusion and passivation steps?

Conrad Burke: Without getting too technical for your readers, what actually happens is that the silicon ink interacts with the crystalline silicon wafer, whereby it allows a selective doping of the wafer, and it allows for the creation of what we call a selective emitter-type structure on a cell. So you get a more efficient collection of electrons in the photovoltaic process, so you get more current than you would otherwise collect from the solar cell.

Innovalight's solar ink allows a selective doping of the wafer, increases the baseline efficiency by an absolute 1%

What is quite unique about this process is that it leverages an already installed base of many gigawatts of solar cell manufacturing that is out there, predominately, as you might guess, in Asia: China, Taiwan and Korea.

So it is a very simple addition to an already existing platform where you continue to make your solar cells like you always have made them, but by employing our silicon ink into our process, you get better conversion efficiencies and better collection of electrons, and therefore you get higher output than you otherwise would from a solar cell.


Solar Server: How is this different to other selective emitter processes?

Conrad Burke: Well, selective emitter isn't a unique concept. It's been around for a long time. The challenge with selective emitters and the challenge a lot of the novel solar cell architectures, if you will, that exist in research labs, or in institutions around the world, is that in order for them to have any effect they need to be mass manufacturable. They need to be mass manufacturable with high yields, over 99%. They need to be able to also have simplified tools that already exist in the marketplace.

What Innovalight has been able to do is employ a very simple process. In order to print the silicon ink on a silicon wafer to make a solar cell, the tool that is used is an industrial screen printer. And those screen printers are already pervasive in the industry, in silicon solar cell manufacturing today.

For example, in a typical solar cell manufacturing factory, at the back end process, just before the solar cell is completed, a screen printer is used to print the metallic contacts on the wafer, or on the solar cell. So that same screen printer, which is made by companies such as Baccini, or Asys, or DEK, those printers are already used throughout the whole food chain of manufacturing solar cells. So that same screen printer can be used to print out silicon ink on the front end of the process.

So the tool we use is already well known, the process has an extremely high yield, which you have to have for manufacturing, and it is simplified by the fact that you need only one step.

So yes, there are other ways to make a selective emitter, however in almost all cases those technologies are unproven. They use lasers, they use many new steps that are unproven. They certainly don't have the yield. And more importantly, Innovalight is the only company is that is in mass manufacturing. I should say, Innovalight's technology is the only technology that is in mass manufacturing in solar cell manufacturing today, that we know of.

So I think that tells you something.


Solar Server: I did read that read that Centrotherm has recently started mass manufacturing in a Chinese fab with selective emitter technology, that would be last week. So there may be a development.

Conrad Burke: Well, without commenting specifically on particular companies, the truth is in the details. Our customers have produced millions of solar cells using our process. Any other technique that we have seen by other companies have only been able to produce hundreds, maybe a few thousand demo cells.


Solar Server: Thank you for that clarification. I have noted that a number of large PV cell manufacturers have signed contracts to incorporate Innovalight processes, that would be Yingli, JA Solar, Hanwha Solar One, JinkoSolar and now Motech. Do you feel that Innovalight's silicon ink process could become an industry standard? And what would be the barriers for other companies to adopt this technology?

Conrad Burke: Our vision is to have this as a universally adopted process in the production of solar cells, in the same vein that silicon nitride is used, or in the same vein that silver is used for metallic conductive electrodes in the back-end process. So we look at silicon ink as becoming a de facto part of manufacturing of a solar cell. Our vision is that this ink is actually printed on the eight to ten billion crystalline-based solar cells that will be manufactured over the next couple of years.

I think the barrier to entry in terms of replicating our technology is rather high, and I say that because Innovalight is the only known mass manufacturer of this type of material. The process to produce the material is a well-guarded process within Innovalight. We produce and we continue to produce only at Innovalight the material.

So that's one thing, and obviously we have 60 patents to protect our materials, and our processes. I think the barrier to entry, at least at Innovalight, would be at least 100 man-years to develop the process to manufacture this ink.


Solar Server: We see a large number of potential process improvements being researched in the PV industry, including the other selective emitter technologies you mentioned. Yet very few of them seem to make it to commercialization. Can you talk further about the process of developing, marketing and selling Innovalight's silicon ink process, and how you have been able to distinguish this product from other potential process improvements?

Conrad Burke: Well, I think the distinction that we bring is simple. It uses one step, and a screen printer, that's again already a proven tool that's used in the industry today. From the adoption perspective, it is the easiest for customers to identify with. I think secondly it brings the highest results. I think we can get twice the efficiency improvement from any other currently marketed selective emitter approach, I think that's also a very important factor. And I think thirdly, the demonstration of results has shown that Innovalight's customers have produced the most solar cells using our technology than any other marketed solution known today.

That's not to say there won't be competition. I think that's good, and I think there can be a couple of winners in this space. But I think Innovalight has clearly carved out a front lead in this space. 

So in terms of sales we have a sales vice president, a sales team, we have put a sales office in China. The fact is that 80% of the world market for solar cells is based on crystalline wafers. And the very fact that 80% of the crystalline solar cell manufacturing now is in Asia. Taiwan and China alone make up about 80%, so it goes without saying that our focus is where 80% of the activity is, and that is in those regions.

So we have opened a sales office in China, we have added three people now in China. We have a representative in Korea and in Japan, and we will soon have somebody in Taiwan. So we certainly are quite intimately involved in our customers in that regard.

We do have a unique capability at Innovalight that I think is very different from any other material, or any other process, or any other tool manufacturing company that is in the solar cell space today. We have at Innovalight, in Silicon Valley in California, a factory, or I like to call it a training line; a small 10MW solar cell capable training line. These are real world tools.

It is arguably the smallest solar cell factory in the world. And I say that because we use that as a training vehicle not only for our processes and our continued development, but more importantly, we use it as a vehicle for training our customers.

So our customers come, and they train and learn the process to print silicon ink onto their wafers at our site in California. Using tools, which, by the way, are the very same as they have in their factories, obviously at a much grander scale than we have. But it is a very easy transfer that makes it unique.

There are only two sites in the whole of the United States that have this capability for customers. One is at Georgia Tech University. And the other is at Innovalight.

We have a unique capability that differentiates us greatly from other companies that are trying to get into the space in the sense that we make the material and we have a demonstration line that exactly replicates what exists for all of the customers in China, Taiwan and around the world. So the transfer process, the learning process and training process is greatly simplified and greatly expedited by having such an asset.


Solar Server: I noted that in April 2010 Innovalight set a target of 20% efficient solar cells. Can you comment on progress made towards that goal?

Conrad Burke: We continue to make progress improving the conversion efficiencies of cells. We have other architectures, we're not just focused on the selective emitter. That's an important point that I think is worth mentioning. We're trying not to get compared to other selective emitter processes, because that's too narrow a comparison.

Yes, certainly our first product and our first entry into the market is based on selective emitter, but Innovalight is aggressively working on alternative and evolutionary approaches beyond the selective emitter, which again, are under the theme of simplified manufacturing using existing tools and the fewest steps possible to improve efficiencies to 20% and beyond.

So we do not like to necessarily be compared only to selective emitters, because the story is much broader than that. Having said that, yes, we continue to make very good efficiencies. We have a development in place to further improve efficiencies, but I don't want to get into the specifics. We will talk about that at some future time.


Solar Server: Is there anything that we didn't cover that is important for our readers to know about your company and your process?

Conrad Burke: I think you got the main elements. The process to make the ink is quite involved. It is a gas process, it uses a cold plasma process to produce perfectly crystalline 5 nanometer particles. These particles are then dissolved in chemicals that we have developed at Innovalight using tools that we have developed.

So it's a very well protected and very efficient process, using technology that we have developed over the course of 100 man-years of development.



Interview by Solar Server International Correspondent Christian Roselund
conducted on January 26th, 2011