Far-Field Enhancement by Silver Nanoparticles in Organic Light Emitting Diodes Based on Donor−π–Acceptor Chromophore

Enhancement in brightness and luminous efficiency has been harvested by the incorporation of silver nanoparticles (Ag NPs) at ITO: 4,4′-bis­[N-(1-naphthyl)-N-phenylamino]­biphenyl (NPB) interface, using 4′-(1-(4-methoxyphenyl)-1H-phenanthro­[9,10-d]­imidazole-2-yl)­styryl-N,N-diphenyl­[1,1′-biphenyl]-4-amine (MPID-TPA) as emissive layer. The enhanced device performance was obtained with 35 nm distance between Ag NPs and emissive material (MPID-TPA). The Ag NPs deposited devices easily inject holes into NPB layer that results in stabilized vacuum level of anode and increase of the current density of OLEDs. The combined effect of far-field plasmonic coupling and hole injection ability of Ag NPs at ITO:HTL interface is the probable reason for the enhancement. A turn-off emission of MPID by Ag NPs and turn-on emission of MPID with the Ag NPs etched by H2O2 formed from the enzymatic oxidation of glucose have been analyzed.