Renewable Energy: Progress in Solar PVs published 2015 (blogged here b"better late than nevers?)
NB. slim on strategic materials, and hence on cost.
"Swiss researchers have developed an affordable and scalable way to make atom thin films of tungsten diselenide for converting solar energy into hydrogen. The method, which exploits the interface of two layers of liquid to act as a ‘rolling pin’ to form the films, could bring the goal of cheap solar cells for hydrogen production a step closer."
One of a number of such approaches is reported Chemistry World with interviews and comments from reputable critics in the field.
COMMENTS in Chem World by
John Turner, who investigates hydrogen energy at the US government's National Renewable Energy Laboratory, is unimpressed.
Co-author of the paper, Kevin Sivula underlines the advantage of low cost processing
While agreeing that improvement is needed but argues that it is difficult to imagine a less-expensive technique than solution-based processing.