Promising?

Upgrade helps solar harvest (Science Alert)

University of Sydney researchers Dr Tim Schmidt and Professor Max Crossley have come up with an ingenious low-cost device to harvest low energy photons, with the potential of significantly boosting the efficiency of conventional solar cells using a process called upconversion...

The findings, which are published in the most recent issue of the journal Physical Chemistry Chemical Physics, pave the way to boosting the efficiency limit to over 50 per cent under the standard solar spectrum and up to 63 per cent under 100 fold solar concentration.

Sounds too good to be true.

And besides: how do you store all the energy they create for more than a day?