Don't hold your breath. The antireflection coatings and photonic crystals required to reach LED efficiencies would be much more complex (expensive) than the LED

Don't hold your breath. The antireflection coatings and photonic crystals required to reach LED efficiencies would be much more complex (expensive) than the LEDs themselves. This is just grant fishing. It's not going anywhere. Similar technologies are potentially more useful for thermophotovoltaics, but even there they aren't cost effective.