Moving the Goalposts (Again) for Organic Photovoltaics: When Will Commercialization Come?
Published: February 18, 2015 Category: Renewable Energy

Organic photovoltaics (OPV) has continued to draw focus of much research as an alternative solar technology, because of the allure of its core attributes: it's lightweight, flexible, inexpensive, highly tunable, and potentially disposable. Yet OPV has spent the better part of a decade struggling to translate these competitive promises from labs toward something that could be commercially successful.

Expectations for OPV stalled again in 2012 largely due to the demise of Konarka, which arguably was the closest to a real-world product and with plans for large-scale factory output. In the end it also was held up as a poster child for attracting massive amounts of investments (several hundred million dollars at the end) with very little to show for it.

Surveying the OPV landscape today, we still see a sector striving to make early lab-scale results translate into real-world products. The goalposts clearly have pushed back yet again. However, there are some encouraging signs that the technology really is moving closer to commercial readiness — and perhaps even knocking on the doorstep, if one believes the most optimistic views — enough to put some early market traction within reach.

The Optimists: Technology Marches Forward

Companies such as Heliatek, Belectric (which picked up some of the Konarka technology), Mitsubishi Chemical, and Toshiba have taken up the mantle alongside promising startups. Some key industry partners such as AGC Glass Europe and Armor Group have strategically committed to OPV's eventual success. Such supporters point to progress being made in a number of areas:

Conversion efficiency:  Two years ago record efficiencies in labs were in the 9-10 percent range for tandem cells and 8-9 percent for some single-cell OPV with different architectures. Today those levels have boosted to 11-12 percent, for both polymers and small-molecule OPV, and 5-7 percent now on pilot production lines.

Lifetimes:  Perhaps the bigger hurdle is in device reliability and lifetimes. Much more work has to be done here, but Heliatek claims it could hit 10 years shortly and has “very good data” showing how to get 20 years' lifetime. Longer lifetimes will be critical to cracking into the promised land of BIPV markets.

Device architecture and materials: Much of those efficiency and lifetime gains are to be credited to improvements in cell architecture, including tandem- and triple-junction cells, which some claim is needed to get the next jump in efficiencies to 13-14 percent where they'll need to be. As much or more credit goes to research into new materials such as new transparent electrode materials (such as silver nanowires and metal meshes) and non-fullerene acceptors.

Processes:  In terms of actual OPV manufacturing processes, work continues in areas of large-area monolithic panels and thicker junctions to improve yield. Various research programs (Technical University of Denmark, Fraunhofer Institute for Applied Polymer Research, the Solliance collaborative project) is pressing forward to show printing of multiple layer stacks and with inkjet printing processes.

Pilot production lines:  Heliatek currently has a 1200 m2 line operating at two-three runs per week, currently doing tandem cells. Rather surprisingly, CSEM Brazil — a subsidiary of the nominal nonprofit Swiss Centre for Electronics and Microtechnology (CSEM), with backing from local private investors — says it has an even bigger OPV R2R pilot line running in Belo Horizonte since September 2014, claiming capacity of 5,000 m2/month and producing a fully functional 800 cm2 1 meter long module.

Field projects:  Several recent field test installations aim to show OPV in several different BIPV contexts. In late 2014, Heliatek announced three pilot installations: in a glass facade, in concrete, and attached to a polymer inflatable building shell. Earlier in 2014 Mitsubishi Chemical and Taisei debuted an external wall building unit using OPV cells as part of a zero-net-energy building (ZEB) project.

The Doubters: Managing Expectations, and Late to the Party

While acknowledging that progress continues to be made in OPV technology, and key suppliers certainly seem convinced that market readiness is imminent, it must be pointed out that OPV still has promises to live up to, and challenges to overcome. It's important to remember that we're still talking about OPV largely in terms of what's being improved in a lab — as always, there's a large gap from there to achievement in an actual production line.

It’s also important to remember that next steps now being taken involve initial pilot manufacturing, with what is hoped to be a smooth transition into eventual full-scale production. Yet this too is often not so simple, and it’s also several years away from fruition. Heliatek shortly will officially begin raising funds (around €60-€70 million) for a proposed large-scale factory to begin in 2016 and be ready within three years. Much can happen in that timeframe, between securing enough investments to actually getting the technology to work and scale as planned at bigger scale.

Moreover, OPV has some serious competition for its intended target markets. Flexibility and low-light performance (including transparency) might give OPV inherent advantages against silicon-based rigid modules, but other solar PV technologies make similar promises — and arguably are further along the commercialization path. Dye-sensitized (DSC), for example, with which OPV shares some roots, has visibly pulled ahead in multiple ways: efficiency levels, pilot projects, and key partnerships, although it too still suffers from lifetime concerns.

Thin-film copper-indium-gallium-(di)selenide (CIGS) also promises better flexibility and low weight, and with significantly higher efficiencies now in the ballpark of c-Si panels. The CIGS-based Dow Powerhouse shingle has been available for several years now. The CIGS supplier landscape is littered with failed aspirants, but many continue the pursuit, notably Hanergy, Manz, and Avancis. The technology still has to be further stabilized, but NanoMarkets does see CIGS finding its footing at pushing at least into BIPV glass and roofing.

And then there's the new solar technology darling: perovskites, which has dazzled researchers with early signs of astonishing potential for high conversion efficiencies through cost-effective wet-chemistry processing. This technology, which we might call “next-generation DSC,” is far from any production-readiness, including a more basic understanding of how it works, but it has attracted incredible interest among researchers and cannot be ignored.

OPV End Markets: Decisions, Decisions

One thing that hasn't really changed is the dual nature of OPV's perceived end-market strategies: off-grid charging applications and grid-connected systems, mainly building-integrated (BIPV) and building-applied (BAPV).

Energy harvesting cells, portable solar chargers (including new sectors such as wearable electronics), and visible and near-IR photodetection are areas where very low (single-digit) power conversion efficiencies are acceptable, when balanced with other capabilities such as thinness/flexibility and low cost. Importantly, a few years of lifetime is often sufficient to last as long as whatever they're attached to, be it a pack or table awning.

For BIPV, efficiency requirements may not be as lax but there is still a similar trade-off among other desirable factors such as low weight, flexibility, and able to be integrated into a building's design — e.g. curtain walls and semi-transparent windows, vs. simply bolted on the roof. Longer lifetimes are a higher priority; early expectations are 10 years, but in recognition that 20+ years is most desirable to really open up these markets.

Another end-market that has a conceivable play for OPV is automotive, leveraging a highly transparent flavor of OPV to pair with vision glass. Not coincidentally, this sector also has sniffed around organic lighting (OLED). This might suggest a favorable pairing between OLED and OPV, although we note that thin-film CIGS appears to be making inroads here as well.

Most suppliers are adamant that BIPV is where the necessary volumes are to generate real revenues and profits for OPV, and higher field performance will happen soon enough to reward those with a little more patience. On the other hand, some others think the efficiencies and lifetimes clearly are too low today to really gain traction in BIPV, so they'll go after solar charging applications instead where applications — if not profit margins — seem broadest.

It seems to NanoMarkets that to fulfill OPV's promise of high-volume low-cost production processes, there needs to be, logically, enough volumes to achieve economies of scale. It seems clear that will have to come from BIPV markets, with the caveat that performance improvements can be realized in actual production (for which suppliers are quite confident). Solar charging applications represent compellingly large conceivable addressable markets: over a billion humans have no electricity access today and likely remaining so for the foreseeable future. Less stringent performance requirements allow for inroads sooner (Eight19 and CSEM seem to be going in this direction). But these application areas seem too fragmented, lower-value, and in regions where a path to sustainable revenues is largely uncertain.

So When Will OPV Be Ready?

In the end there remains the one overriding question for OPV: when will the persistent enthusiasm translate into market delivery and profitability? As we look at both the state of the supply chain and the state of the two major end-markets, NanoMarkets basically sees the OPV market much as we always have: we're still maybe five years out from OPV truly establishing a strong foothold (meaning BIPV). Even today's OPV industry supporters express, with varying degrees of concern, how many more years will pass before OPV is not just “production-ready” — which one could argue is more a euphemism than an achievement — but is actually a competitive product (ideally in multiple forms) that generates substantial revenues and profits in target markets, most especially BIPV.

In the end, we still don't envision much near-term success for OPV, and marginal achievements over the medium- and longer-term for its core target BIPV markets. While we are encouraged by ongoing progress, our warning about market entrance still rings true: we don't see how OPV can slip much further behind when competition seems to pull ahead.

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