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