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