Efficient triplet exciton confinement of white organic light-emitting diodes using a heavily doped phosphorescent blue emitter

Autor: Hoe Min Kim, Ji Hoon Seo, Seung Soo Yoon, Seok Jae Lee, Jun Ho Kim, Young Kwan Kim, Kum Hee Lee
Rok vydání: 2010
Předmět:
Zdroj: Thin Solid Films. 518:6184-6187
ISSN: 0040-6090
DOI: 10.1016/j.tsf.2010.04.049
Popis: We demonstrated efficient white electrophosphorescence with a heavily doped phosphorescent blue emitter and a triplet exciton blocking layer (TEBL) inserted between the hole transporting layer (HTL) and the emitting layer (EML). We fabricated white organic light-emitting diodes (WOLEDs) (devices A, B, C, and D) using a phosphorescent red emitter; bis(2-phenylquinolinato)-acetylacetonate iridium III (Ir(pq) 2 acac) doped in the host material; N,N′-dicarbazolyl-3,5-benzene (mCP) as the red EML and the phosphorescent blue emitter; bis(3,5-Difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (FIrpic) doped in the host material; p-bis(triphenylsilyly)benzene (UGH2) as the blue EML. The properties of device B, which demonstrate a maximum luminous efficiency and external quantum efficiency of 26.83 cd/A and 14.0%, respectively, were found to be superior to the other WOLED devices. It also showed white emission with CIE x , y coordinates of ( x = 0.35, y = 0.35) at 8 V. Device D, which has a layer of P-type 4,4′,4″-tri(N-carbazolyl)triphenylamine (TCTA) material between the HTL and TEBL, was compared with device A to determine the 430 nm emission peak.
Databáze: OpenAIRE