The initial OLEDs used {HEAD ~ emissive molecules} that emitted light from {TAIL ~ their singlet states} as disclosed, for example, in U.S. Pat 
The initial OLEDs used { HEAD ~ emissive molecules } that emitted light from { TAIL ~ their singlet states } as disclosed , for example , in U.S. Pat
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH