White light generation combining emissions from exciplex, excimer and electromer in TAPC-based organic light-emitting diodes

By investigating the electroluminescence of bilayer organic light-emitting diodes based on 1,1-bis((di-4-tolylamino) phenyl) cyclohexane (TAPC) and 2,9-dimethyl-4,7-di(phenyl)-1,10-phenanthroline (BCP), a new emission maximized at 480 nm from TAPC/BCP interface was observed and it was confirmed to be an exciplex emission of [TAPC*BCP]. We found that the emission intensity of this exciplex increases with only increasing the thickness of BCP layer from 10 nm to 30 nm in bilayer device ITO/TAPC(60 nm)/BCP/Al. Being the hole-blocking BCP layer in the bilayer devices, the combination of electromer emission and excimer emission from TAPC, as well as exciplex emission from TAPC/BCP interface, provides a simple way to obtain white light emission. (C) 2009 Elsevier B.V. All rights reserved.