White emission via electroplex formation at poly(N-vinylcarbazole)/ 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline interface

The photoluminescence (PL) and electroluminescence (EL) properties of OLEDs based on poly(N-vinylcarbazole)(PVK) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) have been studied. A new emission at 595 nm has been observed in EL spectra but not in PL spectra of the devices.We suggest the new emission originates from the electroplex occuring at PVK–BCP interface. White emission via electroplex has been obtained in all the OLEDs. CIE coordinates of device ITO/PEDOT:PSS/PVK/ BCP/Alq3/LiF/Al is (0.31, 0.33) at 18 V. Alq3 layer plays an important role in tuning the recombination zone and enhancing the electroplex emission.