By Cynthia Challener
Organic PV (OPV) and Dye-Sensitized Cell (DSC) PV have arguably been the two PV technologies that have struggled the most when it comes to making progress toward high-volume commercialization. This is for several reasons including cost, conversion efficiency, and durability. In direct competition with inorganic thin-film PV and crystalline silicon PV, OPV and DSC simply cannot compare on these fronts. Instead, OPV and DSC are being forced to compete in lower-volume areas where their unique advantages (mentioned below) exclude competitive PV technologies in some way, and cost and conversion efficiency are less critical factors.
Nonetheless, OPV and DSC both have many things going for them in terms of competitive advantages: they can be made transparent with minimal additional development; they are probably the two best PV technologies for using printing and other low-cost manufacturing processes; they lose only a small portion of their output in indirect or dim light; and OPV in particular can be made more flexible than other PV technologies. It is not entirely clear yet, how these advantages will be capitalized on to make real products, but what is clear is no one is going to make any money out of OPV or DSC unless there is 1) a cost-effective method for strongly encapsulating them and 2) a settled approach to creating OPV and DSC on flexible substrates.
Encapsulation Opportunities for OPV and DSC
With regard to the first of these items, OPV and DSC face a very tough problem. Both these technologies have considerable need of a rigorous and effective encapsulation technology and neither really have the money in their Bill Of Materials (BOM) to pay for this. In the past, manufacturers of high-end encapsulation systems have expressed frustration in interviews with NanoMarkets that they are unable to get OPV firms to pay for encapsulation that they clearly need.
That OPV and DSC firms need better encapsulation is almost beyond doubt. Outdoor OPV and DSC applications are central to the business case for any OPV/DSC panel manufacturer and in some cases (PV panels on roofs, for example) their products are supposed to survive outdoors for a very long time. On the other hand, the organic materials from which OPV, in particular, is made are very vulnerable to the elements. No one would seriously consider making outdoor OLED displays at present for just this reason, but such displays would use materials that are fairly similar to those used in OPV.
On the face of it, there are two solutions to the encapsulation problem that the OPV and DSC industries face. One is to avoid the problem by only producing products that are not constantly exposed to the weather. Unfortunately, these are fairly few and far between and consist largely of battery chargers and some novelty products. Still, not surprisingly, it is with these applications that the OPV and DSC panel makers are beginning. The big challenge for the OPV and DSC firms is moving beyond this point. If they don’t move beyond this point, they will never be able to grow their businesses to a reasonable size. Battery chargers do not use much PV material.
The other solution is to spend more on encapsulation. But there is very little money in the OPV or DSC Bill Of Materials (BOM) for encapsulation. This is not because of a Scrooge-like mentality on the part of the OPV/DSC industries but rather because spending more money on encapsulation may make a bad situation worse in terms of overall costs for OPV and DSC. The hard fact of the matter is that OPV and DSC have never been able to achieve the cost advantages that they were supposed to offer according to their advocates of a few years back. Adding to cost with expensive encapsulation materials is hardly likely to help achieve rapid commercialization of OPV and DSC or achieve the cost expectations that have been built into the OPV/DSC value proposition over the past years.
The bottom line then is that without better encapsulation, OPV and DSC firms may be forced to rely on tiny market niches in order to eke out a living. But if they spend more money on encapsulation, they make their technologies even less cost-effective in a market environment in which they are already having problems in this regard.
Of course, the OPV and DSC manufacturers and proponents are well aware of these problems and realize that encapsulation technology is potentially a powerful enabling technology. This is why encapsulation is a major topic of discussion at OPV or DSC technical meetings. This is in contrast to the inorganic thin-film PV and c-Si PV industries, where talk of high-barrier encapsulation is almost an afterthought.
NanoMarkets believes that because of all this there is a huge opportunity for firms in the encapsulation space to solve OPV’s and DSC’s encapsulation problem. This is the same thing as saying that for encapsulation firms to make money in the OPV/DSC space they must come up with forms of strong encapsulation that cost no more (and hopefully less) than today’s encapsulation systems. If they can do this, the OPV/DSC industries will reward the encapsulant makers, not with higher prices, but with large orders that might make up, in time, for the absence of high prices. And because, the OPV/DSC firms cannot easily expand into the area of large outdoor panels, which they need to do to create viable businesses, encapsulation may be the key to survival of the OPV/DSC industries, which have a long way to go to meet their early expectations.
Substrate Opportunities for OPV and DSC
OPV and DSC also create opportunities with regard to substrates that are intimately related to the substrate issues that are discussed above. Yet, another key advantage of OPV and DSC is said to be their ability to be created on flexible substrates. But encapsulation on flexible substrates is even harder than on rigid substrates, so that increases the opportunities and challenges in the encapsulation area that are discussed above.
On the other hand, flexible substrates are potentially lower cost than glass, which promises lower total materials costs for OPV/DSC panels. This is not only a good thing in and of itself, but, if implemented, makes a little more room in the OPV/DSC BOM for more money to be spent on encapsulation. The emphasis here should be on the word ‘little’ since, for the most part, flexible substrates (metal foils or expensive polyimide) have in the past been only modestly less expensive than glass. Nonetheless, flexible substrates imply the use of R2R processing and this too can reduce costs.
An interesting area of opportunity related to all this is the role of printing in reducing costs. Not only does printing present all the economies associated with R2R processing, but since it is a low-temperature process, may mean that high-temperature polyimide substrates can be shunned in favor of low-temperature plastics (such as PET), reducing substrate costs by perhaps an order of magnitude. In time, this would mean opportunities for suppliers of inexpensive plastic films like PET to enter the OPV/DSC substrate market in volume, and for the OPV and DSC manufacturers to produce a cost advantage by using these low-cost materials.
OPV, DSC, BIPV and Substrates
A completely different strategic direction is also important to consider with regard to substrates. One of the markets that OPV and DSC are chasing after is the building-integrated PV market. In this market, there is the chance for OPV and DSC to plug into a high value-added opportunity with all that this says about potential profitability. Whether this means there will be more money to spend on encapsulation or not remains to be seen.
What it does mean is that OPV and DSC will have to contend with an entirely new range of substrates including tile and perhaps even wood, as well as new forms of plastic and architectural glass. Much of this is undiscovered territory for OPV and DSC, but still worth exploring now for near-term future opportunities. One possibility that capitalizes on the unique ability of OPV to be transparent─no other type of PV can claim this─would be some kind of fully transparent grade of BIPV glass. Here is an idea that has a large addressable market and that only PV based on organic materials can generate revenues from. This substrate-related opportunity is exactly the kind of thing that the OPV/DSC market is looking for.
Cynthia Challener is a Contributing Editor for NanoMarkets(www.nanomarkets.net) and also contributes to publications such as Chemistry & Industry, ICIS Chemical Business, JCT CoatingsTech, PPCJ and Speciality Chemicals magazines. Cynthia received her B.S. in Chemistry from Stanford University and her Ph.D. in Organic Chemistry from the University of Chicago. She worked as a Principal Research Chemist at ARCO Chemical Company and Technical Services Director for flavor and fragrance producer, Bedoukian Research prior to starting her own business.
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