Incident sunlight is a good source of IR, obviously, but with some wavelength tuning, the new tech works perfectly well on reradiated IR too, meaning you can harvest from the ground, sides of buildings, etc., where you don't have cells installed.
And they've already prototyped a roll-to-roll manufacturing process onto polyethylene film, so that you wouldn't have to somehow attach rigid (and thus fragile) tiles to your roof: You'd just unroll this stuff and staple it down.
Holy cats. This could be seriously huge. They say that industrial-scale application is still years away -- for one thing, the electricity is generated at terahertz frequencies, so they've got to find rectifiers that will (a) work and (b) be cheap to incorporate.
But several of the biggest technical hurdles are already in their wake.