Improved performance of electroluminescent devices based on an europium complex

Abstract

Electroluminescent (EL) devices using an europium complex Eu(DBM)3 bath as the electron-transport emitting layer were fabricated. The quenching effect of the metal cathode and the unstable nature of the Eu complex under EL operation markedly influence the EL efficiency. By keeping the emitting area far from the metal cathode and partly doping the Eu(DBM)3 bath layer with a hole-transport material, the EL performance was significantly improved. Sharp-band red emissions with turn-on voltage of 3 V, brightness of 820 cd/m2, and external quantum efficiency of 1% were achieved.

Photovoltaic effects of diodes containing lanthanide complexes

“…When a hole-transporting material (donor) and an electron-transporting material (acceptor) are in intimate contact, either in a blend/mixture or at the interface between the two molecular solid films, exciplex (excited state complex) can be formed through charge transfer between an excited state molecule and a ground state molecule [9][10][11][12]. Some of exciplex emissions could be used to obtain white light emission or to tune EL emission color from multiplayer LEDs [13,14], however, an exciplex emission must be generally suppressed in order not to bother color purity in EL devices [15].…”

High yield luminescence of a novel europium complex by excimer excitation and f–f absorption of Eu3+

“…OLEDs with red phosphor (platinum and iridium complexes) [5,6] and green phosphor (tris(2-phenylpyridine) iridium(III)) [7] have showed very high quantum efficiency. Lanthanide complexes have been anticipated to fabricate high efficiency OLEDs with narrow emission peaks [8,9], and great achievements have been gained in improving the brightness and electroluminescence (EL) efficiencies of OLEDs with europium(III) and terbium(III) organic complexes as luminescent centers [10]. However, OLEDs using lanthanide complexes have exhibited relatively low electroluminescent quantum efficiency [11].…”

Synthesis, structure and photoluminescence of novel lanthanide (Tb(III), Gd(III)) complexes with 6-diphenylamine carbonyl 2-pyridine carboxylate

“…The strongest transition, 5 D 4 → 7 F 5 , occurs at approximately 544 nm, the narrow intense green terbium luminescence [5]. Several ternary rare earth complexes have been applied to prepare OEL devices that showed weak visible emission and low electroluminescence efficiency [6][7][8][9]. In principle, electroneutral metal complexes may form uniform thin film in vacuum vapor deposition and are reasonably stable to heat, which is required for OEL displays [10].…”