Phosphorescent-photovoltaic light source
I have attached a drawing, so that you could better understant the priciples of such a device.
The basic idea is the same as in another artcile, the difference is that this time we are collecting light which would be simply lost otherwise.
I will explain how this device works (if you have not already figured out) so gentlemen here we go:
The supercapacitor or rechargeable battery is precharged and inserted into the circuit. Ignore the diode (6) because it is pointless to explain what it does, since it does exactly what it has to do. The LED (5) illuminates both the photovoltaic cell, but also the phosphorescent plate, the light is absorbed by the photovoltaic cell both from the LED, and from the phosphorescent plate, which emits the absorbed light. At the base of this system is a slot through which the "lost" light can be reused eventually by exposing another photovoltaic plate of smaller dimensions.
Keep in mind that this is not tested yet, maybe it never going to be.