Researchers from RIKEN (Japan) developed a new efficient copper complex that can be used to replace Iridium phosphors in OLEDs - and would be much cheaper (copper is about 1/2000 cheaper than Iridium).
The researchers altered the molecular environment in which the copper sites - wrapping each copper ion with a newly designed organic ligand. The ligand forced the copped to become three-coordinate (three bonds to the ligand), rather than the usual four. This caused the efficiency (EQE) of the copper complex to increase dramatically.
The researchers developed a green emitter, and now their plan is to proceed to create red and blue ones as well.