25 Jun 2012
Despite a volatile market and the high-profile bankruptcy of Konarka Technologies, two UK firms see a future in organic photovoltaics.
by Andrew Williams
The global photovoltaics market is facing some stiff challenges right now, but things look particularly tough for companies involved in the emerging organic photovoltaic (OPV) sector.
That was notably demonstrated by the recent bankruptcy of Konarka Technologies. Along with Germany’s Heliatek, the US company had been viewed by many as leading the development of the technology out of the laboratory, with world-leading efficiency marks and a string of venture capital deals.
With Konarka folding, what does the future hold, and will a modest but growing number of UK-based start-ups targeting the sector be able to carve out a successful niche?
The Konarka lesson
According to Jonathan Melnick from the cleantech analyst firm Lux Research, the OPV market is currently worth less than $10 million – tiny by any measure, and only a small fraction of that is coming from the UK. Although there has been some minor growth related to niche applications in recent years, the OPV sector as a whole is clearly still an extremely small portion of the overall solar 'landscape'.
"OPV has several technical limitations that make it uncompetitive with other solar technologies - including significantly higher cost, lower efficiency, and shorter lifetimes," Melnick says.
In his view, it was a combination of these limitations that led to Konarka’s downfall. Driven by the promise of cheap, printed solar modules that can be made colorful and transparent, Melnick says that “technically unsavvy” investors rushed to back the company, in the mistaken belief that it would build a 1 GW OPV manufacturing line – while in reality he felt the company would never come close to that capacity.
"With ten times higher cost, and ten times lower efficiency and lifetime compared to alternative solar technologies, the math never added up for Konarka’s ‘Power Plastic’,” he says. “Konarka’s underlying technology was never market ready and its failure was no surprise.”
"Finding market success in emerging technologies takes many factors, but a viable technology underpins all of them, something that Konarka never had - and [had] no credible path to attain. OPV developers attempt to find markets that can leverage its differentiated properties. For example, OPV can have color variability in building integration. However, none of OPV’s properties have been demonstrated valuable enough to overcome its significant limitations," Melnick adds.
Despite that bleak analysis, a growing number of UK-based companies believe that they can buck the trend and make good use of those “differentiated properties” of OPV and bring them to market successfully.
According to Kevin Arthur, co-founder CEO at UK-based OPV outfit Oxford Photovoltaics, companies like Konarka, who manufacture on flexible substrates, have a flawed plan – that they are “targeting a small niche or currently non-existent business”, and that the cost of providing sufficient barrier performance with existing polymer systems is currently prohibitive. Oxford has a different plan.
"Our product is manufactured on a substrate that is manufactured globally in massive volumes," he explains.
"Our standard substrate is architectural glass, which gives the best possible barrier properties, while offering a very attractive price point," says Arthur. "We always make the point that buildings are manufactured from our standard substrate, so we have the opportunity to offer the first truly integrated PV product for commercial buildings."
The company is a spin-out from Oxford University, and commercializing the hybrid organic solar cell research of Henry Snaith and his academic team. It produces “solid state” dye-sensitized solar cells (DSSCs), specifically designed to overcome the usual limitations of the technology, such as corrosion, problems with serial interconnection and sealing, as well as limitations on maximum power due to energy loss during the charge generation process.
Arthur explains that Oxford’s approach, based around an organic p-type semiconductor, more closely matches the energy of the holes [charge carriers] in the dye, minimizing voltage loss. Power conversion efficiencies in excess of 7% have been demonstrated and Arthur says that devices incorporating this material can already deliver open-circuit voltages of up to 1.2 V (compared with only about 0.9 V for the original electrolyte cell).
In his view, the main benefit of the system is that it is manufactured using a simple printing process that can be easily scaled in terms of volume and substrate size, opening up the possibility of large-scale deployment in high volume applications such as glazing for commercial buildings.
"We have achieved very good traction with the commercial construction value chain and are exploring a number of high-volume opportunities to supply our modules from 2014 onwards. It’s worth noting that we do not see ourselves as a PV company, we position ourselves as a glazing company that supplies solar power glazing products," he adds.
In June 2011, the company secured seed funding of £700,000 from a combination of angel backers and institutional investor MTI Partners - and is currently in the process of raising a series ‘A’ round.
"We are finishing development of our printing processes over the next ten months, and will then build a pilot production line,” Arthur predicts. “Very high volume supply of products will be addressed in collaboration with established partners in the glass processing industry.”
Another UK company seeking to take advantage of DSSC technology is Cardiff-based G24 Innovations (G24i), which manufactures a dye-sensitized photovoltaic thin film using a roll-to-roll process, and titanium dioxide, a light-sensitive dye and an electrolyte in place of traditional semiconductor materials.
According to COO Richard Costello, as well as being thin and flexible, the energy-harvesting technology also shows “superior performance” under indoor and low light conditions. He explains that there is a significant difference between G24i's dye-sensitized cells and typical OPV material, which he agrees suffer from a number of disadvantages.
To begin with, he argues that standard OPV material provides little or zero tolerance for the point and processing defects that cause yield losses and poor low-light performance. Moreover, OPV structures require five or more ultra-precision coatings of extremely thin layers.
"[E]ven the best practical filtering of fluids, air supplies, cleanliness, process control and defect-acceptable materials would be very difficult to control to obtain high yields and in-spec performance," he says.
"OPV also has an inherent chemistry which alone requires the use of high-temperature organic solvents and is very sensitive to water and air, an order of magnitude more than DSSC. OPV is far more difficult to build from a chemical processing, coating and handling [standpoint] than photographic film negatives.”
Costello says that the G24i cell is far more tolerant of processing defects that would otherwise lead to serious performance degradations, is less sensitive to outside contaminants, and made using a manufacturing process that does not even require a certified clean room designation.
"[Our] technology can harvest indoor or ambient light of very low irradiance, 200 lux or less, at reasonable manufacturing yields, reliably and robustly, utilizing a process easily modified for form factor, scale-up and willingness to easily integrate a myriad of continuous improvements in materials, performance, lifetime and cost," he claims.
Proof of the commercial appeal has now arrived with the news that G24i’s photoelectric modules are being integrated into Logitech's "Keyboard Folio" for Apple’s second- and third-generation iPad. The technology was also recently installed in a number of Las Vegas hotels, to power motorised window shades.
"Future commercialization will continue to focus on low-power consumer electronics, E-paper displays and low-power wireless sensors,” says Costello, adding that as power density steadily increases, new applications and markets will open up for devices with greater power requirements, for example wireless speakers, displays and standby, or 'phantom power' applications.
Financing and market prospects
Despite the optimism of Arthur and Costello, and the genuine emergence of consumer electronics applications, Melnick remains downbeat about the market as a whole. He says that Konarka will not be the last OPV to run out of investor patience and cash.
"OPV start-ups have difficulty raising money because the performance of their technology is lacking [and] unrelated to challenges in other portions of the PV market," he says. “OPV is very immature, so the mainstream PV competition just creates higher barriers once OPV developers think they are ready for market.”
And there is more evidence of that competition lately, with Ascent Solar having just signed a deal to supply 50,000 of its flexible, inorganic thin-film CIGS solar chargers for Apple’s iPhone.
Melnick forecasts only very modest growth for OPV, suggesting that even by 2020 the technology will address only a $159 million market. Of that total, $64 million is expected to relate to defense applications - where cost is no real issue and the flexibility and lightweight nature of OPV can be exploited.
"The biggest barriers are the inherent performance limitations of the technology - cost, lifetime, and efficiency. While these metrics will improve, OPV chases other improving solar technologies, meaning it will not be able to compete on technical performance for a very long time," he says.
Although not as pessimistic as Melnick, Costello admits that, while he cannot speak for other OPV companies, the difficult market conditions have had an impact on any plans that G24i may have had for an initial public offering of stock.
Arthur agrees that the volatility makes it more difficult to raise money but is also keen to stress that Oxford PV has enjoyed “a very high level of external interest” in its current funding round, and is extremely well supported by its existing investors. "There have been no delays to our plans and we remain on target and on budget," he says.
For both the UK firms, the priority is to carve out niches where standard PV technologies do not or cannot compete. Costello says that he does not see a viable market application for OPV once silicon is priced at less than $0.75/watt for utility-scale solar applications, for example. But on the other hand he does see a major opportunity for G24i's technology in the $80 billion global market for household batteries.
Arthur’s equivalent target is in building-integrated PV (BIPV), through applications such as solar windows. "I believe that what we’re offering is the enabling technology to make BIPV a realistic proposition, and we have the support of high-profile customers to make that happen," he says, concluding on a note of pragmatism that perhaps reflects part of the reason for Konarka’s demise:
“It’s not about how cool your technology is, it’s all about what people are prepared to buy.”
About the Author
Andrew Williams is a freelance journalist specializing in business, energy and technology.
|OCT imaging with AI screening improves retinal diagnosis|
|Nanoscribe installs GT2 3D printer in Keio University|
|Dynetics to build 100 kW laser weapon with Lockheed and Rolls-Royce|
|Plessey and Jasper develop GaN-on-Si HD microLED display|
|NIST builds IR thermometer with 'dramatically improved' performance|
|Glass wafer redesign expands field of view in AR, MR apps|