Well for starters it would be rich in rare earth (Y3 Al5 O12:Ce) elements that fluoresce, and be a bit toxic with all that Gallium Nitride and who knows what else dopant they use in the chip.
Then there is the beam width to consider, we would have day/night for 2 months of the year and darkness on the other side of the Sun, unless LED is plural then I think Mrs God would ensure the overlap of the beam widths kept the sunshine sufficiently constant.
And what is generating all that voltage? Think of the power requirements.

And we would have developed an indifference, by now, to the higher Blue light content that currently keeps us alert & more awake at night - one to ponder if you Kindle in bed, &/or replace your bedside lamp bulb for an LED version. If you suffer insomnia - do the research and avoid eco bulbs, fluorescent strip lighting and readers/phones/Flat Screens late at night.

But otherwise worth a try once we have built the crystal growing furnace big enough for the chip(s)!