Occasionally on MetalMiner, we like to report on interesting developments for metal that hold some novel or more futuristic application. Flexible dye sensitized electronic pads on backpacks, tents and other outdoor equipment is one such development. Dye-coated semiconductor nano-crystals are embedded in plastic along with an electrolyte. The dye absorbs light and creates electrons, which are transferred to the semiconductor and then out into a circuit. Dye-sensitized cells have lower light-to-electricity conversion efficiencies than the best thin-film solar cells, typically 10% instead of 30% for silicon based solar cells, but they are considerably cheaper to manufacture and can also be printed on flexible surfaces.
In this situation, the technology is incorporated as a flexible panel on a back pack and generates 0.5kw enough to recharge a mobile phone, GPS or other small electrical device. In addition to cost, the flexible film can absorb light from a wide range of angles meaning you don’t have to be walking north on a sunny day in order to get a decent level of charge, in fact they will even work indoors under artificial light.
Naturally this technology is still at an early stage and is therefore justifying its cost to early adopters as much on novelty value as practicality. Personally I would probably buy a hand operated re-charging device but in time the additional cost of a charging pad on your backpack will become only a small part of the overall cost at which point they will be like an integral water bottle pouch – a common feature on all better back-packs. Of more note is a comment made on Technology Review, the website reporting this development, concerning the metals needed to facilitate the process. The manufacturer of these panels G24 Innovations uses ruthenium dyes coated on titanium dioxide nano-crystals and an iodide-containing non volatile electrolyte. The company says their cells are over 12% efficient at converting light into electricity. But ruthenium is in short supply and demand is rising for a variety of high technology applications. The price is likely to be volatile in the years ahead and if this is a vital part of the current technology, the inventors will need to develop alternatives down the line because it would be a shame for such an interesting product to be made uneconomic by a spike in the price of such a critical rare earth metal.