The electron hole pairs trapped within the active layer sensitize {TAIL ~ the activator ions}, causing the activator ions to emit {HEAD ~ light} 
The electron hole pairs trapped within the active layer sensitize { TAIL ~ the activator ions } , causing the activator ions to emit { HEAD ~ light }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD