TL;DR it's a special kind of solar panel that works better in low light conditions. Super cheap solar panels are around 11% efficient, average cells are around

TL;DR it's a special kind of solar panel that works better in low light conditions. Super cheap solar panels are around 11% efficient, average cells are around 18%, and these are around 29% efficient. So about a 50%-ish improvement. It is a fascinating breakthrough, but unfortunately even if it was 100% efficient indoor solar cells would still be pretty useless. As a rule of thumb indoor illuminance is 200-1000 lux, vs outdoor illuminance up to 120,000 lux. A lux is slightly less than 1.5e-7 watts per centimeter. So for a 500 lux room (which I'd call pretty well lit) with one of these devices the size of a smartphone you'd be harvesting 1.5e-7w/cm2/lux500 lux7cm14cm0.29 efficiency = 0.00213 watts. As cool as this breakthrough is, it's not going to get anywhere. Current solar-powered household devices (pretty much just calculators) don't really need 50% more power, and other household devices need many orders of magnitude more power. Even if it was 100% efficient, it'd still be gathering less than a hundredth of a watt. That's not coming anywhere close to useful.