A few weeks ago, I posted that researchers at Penn State used titanium nanotubes to significantly boost the efficiency of cracking hydrogen from water using solar "photolysis," increasing it from ~6% efficiency to over 13%. In passing, I noted that they also claimed to have improved the utility of dye-based photovoltaics. Details of this latter discovery are now coming out.
A layer of titanium nanotubes roughly 360 nanometers in length gave the dye-based photovoltaics a conversion efficiency of about 3%. That may not sound like much -- and it's not -- but it is equivalent to the typical efficiency of commercially-available thin film and polymer photovoltaics. Moreover, the Penn State team believe that a thicker layer of titanium nanotubes should boost the overall efficiency to over 15% -- equivalent to commonplace silicon solar panels. The advantage here is that dye/titanium photovoltaics would be far less expensive to produce, requiring much less energy and fewer toxic chemicals.