Photovoltaics Shines Brightest for Silver
Published: September 02, 2010 Category: Advanced Materials Renewable Energy
In serving the applications for silver inks and pastes, manufacturers and distributors face a quandary: most of the high-growth markets for silver are relatively small, while the larger markets are already mature and generally offer only modest growth prospects. But the photovoltaics market for silver inks and pastes offers the best of both worlds. This segment is already approaching a billion dollars in annual revenues, but it will grow faster—in absolute terms—than any of the other silver ink categories, and it will challenge traditional thick-film applications for dominance of the overall silver electronics market by the end of the period covered by this report. With all this in mind, this report specifically analyzes the photovoltaics-related markets for silver inks and pastes, in order to provide a comprehensive analysis of the revenue opportunities for firms in this space.
This growth in the use of silver for PV is driven primarily by the growth of PV itself, which is still growing quite rapidly even though it has slowed—and at times faltered—in the last few years.
While PV is certainly not immune to the undulations of the economy—as we saw in the contraction of PV shipments in 2009—it is still one of the stronger components of that economy. In part because this because PV has been spurred by government subsidies, which in turn were put into place because of concerns (valid or not) about the availability and accessibility of fossil fuels and the environmental impacts of extracting and burning them. As an aside, however, we note that without such subsidies, the PV industry has a hard job surviving as the ending of some subsidies in Spain and Japan have proved. In some cases, subsidies are being supported with renewable energy mandates, but there are no guarantees that these mandates will be successful in achieving their goals in the long run and a strong probability that they will not.
All of this suggests that the opportunities available for suppliers of silver and silver products into the PV space are highly dependent on policy consideration, which should be judged a significant risk factor in view the current worldwide financial problems.
We also note that silver itself is a commodity and its price depends on much more than its photovoltaic-related use, or even the whole of the market for silver inks and pastes used in the electronics industry as whole. Besides the industrial uses of silver, silver is also used for decorative purposes (jewelry) and as a store of value in bullion. The economic turmoil of the last few years has increased investment in “hard” assets like precious metals, and silver’s price has been affected by it even as the struggling economy has caused overall industrial silver consumption to be less than robust. This naturally increases the cost of silver for use in photovoltaics and other electronics. Since PV is a cost sensitive factor, these apparently exogenous factors – exogenous from the perspective of the PV industry, anyway – are likely to have a great deal of impact on how silver is used in PV over the next few years.
In particular, higher prices for silver would obviously be a strong signal for PV firms to look for silver substitutes. This is not an especially easy task, since silver is the most conductive material known to mankind. There are sometimes alternatives to the use of pure silver that might not be as good as silver, but are good enough performance-wise and much better than silver cost-wise. However, for most of the electronics applications of silver, including many photovoltaics-related ones, there really is no substitute, and the demand for silver is quite inelastic.
But high and uncertain silver prices do lead silver ink and paste manufacturers to seek to create greater value, in the hope of gaining better margins, or at least preserving their margins. And there is certainly room for innovation here. PV is adopting both novel cell architectures and new materials for the absorber layer and this profoundly affects the materials that are used/required for electrodes and reflector layers; the areas where silver is used in traditional cells.Consequently, new silver ink and paste formulations are needed to match the materials and devices on which they are applied, to improve durability, to lower contact resistance, and to reduce costs. The needs of the PV industry produce a fertile field for silver ink and paste product development.
Crystalline Silicon PV: Old Guard, New Developments
Crystalline silicon (c-Si) PV still makes up the largest share of the PV market and since the end of the (crystalline) silicon shortage, it seems likely to retain its strong position. From the silver perspective, this is surely good news because silver is the main electrode material for c-Si PV, forming both the front and the back electrode in most cells. More specifically, silver products for crystalline silicon PV fall into three general categories: those for front electrodes, those for back electrodes, and tabbing pastes.
This reduction in the risks associated with c-Si as an addressable market is unlikely, however, to be associated with complacency on the part of the silver industry. PV of all kinds is very sensitive to materials costs and new approaches and innovations to reduce the cost of the silver electrodes are coming into play. These innovations include not only ways of making silver more effective as a conductor (nanosilver, platelets and other particle shapes) but also ways of using less silver.
In addition, silver product suppliers who adopt high pricing strategies will have to compete with competitors who come up with non-silver approaches that do not use silver at all; copper and aluminum based replacement of silver are often possibilities. The back electrode is already in the process of substituting silver with other materials, since it is typically less demanding than the other cell parts that use silver. Aluminum-containing materials are being substituted, here.
Nonetheless, there is no getting away from the fact that silver is still more conductive than any other metal—a fact that will not change—and the particles from which silver inks are made maintain their conductivity even when ambient conditions would form non-conducting oxides on other metals. So, silver’s high conductivity, combined with the wide range of physical characteristics producible in formulating inks, will ensure that silver remains dominant for crystalline silicon PV front electrodes as well as competitive for back electrodes.
Thin-film PV: Newer Technologies, Newest Products
Thin-film PV (TFPV) technology made great strides forward at the height of the great PV run-up of the mid-2000s, and continues to grow more quickly than crystalline silicon. But the rapid growth of the mid-2000s was in large part—and perhaps almost entirely—due to the silicon shortage, which prevented crystalline silicon PV from meeting demand. The silicon shortage is over now, though, and so is the age of runaway PV demand. As a result, thin-film PV has been dealt a setback and must compete now on its own merits.
Still, some varieties of thin-film PV have become established enough and efficient enough that they can continue to grow more rapidly than crystalline silicon PV. NanoMarkets expects thin-film PV to become comparable to crystalline silicon PV in both volume and revenue within the forecast period, and, from the silver perspective, this is important, because TFPV uses silver in different ways and in different amounts to c-Si. In general, it is probably fair to say that TFPV uses less silver, so the growing share of the PV market that is represented by TFPV may be seen as a negative by the silver industry to some extent.
In fact, TFPV uses much less silver than crystalline silicon PV. The front electrodes of thin-film PV are typically made of transparent conductors rather than fine silver fingers, although silver grids are sometimes applied on top of the transparent electrodes. Tabbing is virtually nonexistent among thin-film PV, since nearly all cells are monolithically interconnected on a common substrate. And for the back electrodes, the largest manufacturer and technology—First Solar with its CdTe PV—forgo silver entirely in favor of a carbon-based paste containing copper, for reasons of chemical doping. CIGS, on the other hand, uses molybdenum for the back electrode for most cells, for ease of sputtering directly on glass substrates and for good adhesion of the CIGS layer.
For the back electrode of thin-film PV cells, silver plays a different role. It can be used as a reflector, to send unabsorbed light back through the cell’s active layer for a second pass, in addition to serving as the back electrode. Silver’s superior reflectivity combined with its high conductivity makes it a natural choice for this role, and it has been used extensively for thin-film silicon and OPV cells. The cost pressures on CIGS and CdTe are pushing strongly for substitution of other metals—mainly aluminum—for this reflector. However, this is balanced by the increasing use of reflector layers in TFPV, as it moves toward thinner and thinner absorber layers to save costs.
Also, while the quantities of silver used for thin-film PV are smaller than those used for crystalline silicon PV, silver inks manufacturers have developed products specifically for thin-film PV. For example, the fine silver grids on top of thin-film PV’s transparent electrodes are both finer than those used as crystalline silicon PV front electrodes and more difficult to adhere because of the underlying transparent conductors. Special ink formulations are produced to address these challenges.
The bottom line is that both the growth and changes in the PV industry continue to present opportunities for the silver and silver products industries and will continue to do so for the next decade.
Share this on social networks or email
FollowNanomarkets on Twitter
JoinNanomarkets on Facebook
FollowNanomarkets on LinkedIN
Subscribeto the Reports Feed
