It's a PHYSICS award
There is, indeed, some interesting physics associated with GaN (blue) LEDs. That's why the award, not for economics. What bothers me is that they never gave (or included this year) an award to the people who invented LEDs in the first place. (One of them, NIck Holonyak, had a lab just down the hall from mine at the University of Illinois).
There is also some interesting physics going on in a two dimensional sheet of graphene, where the conduction and valence bands have no curvature to them, as well as carbon nanotubes, which are just graphene rolled up into a tube.
However, you must remember, the Nobel prize for physics is only for EXPERIMENTAL physics. They can't give it solely for things like theoretical electron band calculations (for either LEDs or graphene). That's why Einstein's Nobel prize was for the Photoelectric Effect and not for Relativity.