Electrochemical Deposition of Bis(N,N′-diphenylaminoaryl) Substituted Ferrocenes, and Their Application as a Hole-Injection Layer on Polymeric Light-Emitting Diodes

Abstract

The synthesis, spectro-electrochemical study, and electrochemical polymerization of bis(diphenylamino) substituted ferrocenes (Fcs), including the family of the 1,3,4-oxadiazole (OXD) bridged 1,1′-[p-(Ph 2 N)(C 6 H 4 ) n OXD] 2 Fc and the vinylene bridged ferrocene 1,1′-[p-(Ph 2 N)(C 6 H 4 )-(E)-CHdCH] 2 Fc, have been carried out. The ferrocene compounds underwent three stepwise one-electron oxidations to form the (3+) radical cations that further electrochemically polymerized on a Pt or an indium tin oxide (ITO) electrode surface. The polymeric layers showed extremely good hole-injection properties. The polymeric light emitting devices (PLEDs) of ITO/ED-1,1′-[Ph 2 N(C 6 H 4 ) 3 OXD] 2 Fc/PVK:Ir(PPy) 3 :PBD/Mg-Ag showed a turn-on voltage (at 100 cd/m 2 ) of 11 V, with a maximum brightness of 27 700 cd/m 2 . The turn-on voltage was 1.5 V lower than that of the poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) based PLED and 2 V lower than the corresponding electrochemically deposited poly(4-(N,N-diphenylamino)styrene) based PLED.

Ordering the amorphous – Structures in PBD LED materials

“…Refs. [7][8][9][10][11][12][13][14][15][16][17][18][19] provide selected examples for the application of PBD in OLEDs while the review [6] summarizes molecular structures and properties of electron transport materials used for LED applications with specific emphasis on low molecular and polymeric oxadiazole compounds.…”

Electrosynthesis of Aromatic Poly(amide-amine) Films from Triphenylamine-Based Electroactive Compounds for Electrochromic Applications

“…The formed radical cation dimerizes and upon abstraction of two protons yields tetraphenylbenzidine (TPB) [ 36 , 37 ]. The electrochemical coupling reaction of TPA has been used as a convenient and effective method to prepare electroactive polymers for optoelectronic applications [ 38 , 39 , 40 , 41 , 42 , 43 ]. Systematic studies on the electrochemical oxidative coupling of carbazole have been reported by Ambrose and Nelson [ 44 , 45 ].…”

Facile Synthesis of Electroactive and Electrochromic Triptycene Poly(ether-imide)s Containing Triarylamine Units via Oxidative Electro-Coupling

“…It is well-known that unprotected triphenylamine (TPA) and N -substituted carbazoles such as N -phenylcarbazole (NPC) undergo electro-oxidative coupling (dimerization) to tetraphenylbenzidine (TPB) and N , N ′-disubstituted 3,3′-bicarbazyls, respectively [ 28 , 29 ]. With appropriately designed monomers, the TPA or carbazole electrochemically oxidative coupling reaction could be employed as an efficient polymerization method to fabricate electroactive polymer films with potential applications in optoelectronic devices [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. In recent years, we have demonstrated that electrochromic polyamide and polyimide films could be facilely synthesized from the amide- or imide-preformed compounds with terminal TPA or NPC groups through oxidative electro-coupling polymerization [ 38 , 39 ].…”