Hooking up LEDs backwards creates a cooling light?
https://phys.org/news/2019-02-reverse-cool-future.html
In a finding that runs counter to a common assumption in physics, researchers at the University of Michigan ran a light emitting diode (LED) with electrodes reversed in order to cool another device mere nanometers away.
The approach could lead to new solid-state cooling technology for future microprocessors, which will have so many transistors packed into a small space that current methods can't remove heat quickly enough.