title: Simple-Structured Phosphorescent Warm White Organic Light-Emitting Diodes with High Power Efficiency and Low Efficiency Roll-off.
abstract: We present phosphorescent WOLEDs fabricated simply by inserting an ultrathin nondoped orange layer within the blue emissive zone, where an efficient exciplex system is applied as the host. The resulting WOLED shows maximum power efficiency of 75.3 and 63.1 lm/W at the luminance of 1000 cd/m(2). The exciton density profile in the emitting layer, the operational mechanism and the quenching process at high luminance are systematically investigated by experimental and theoretical methods, from which it is concluded that the efficient utilization of excitons via exciplex host and the wide recombination zone are the key factors for the prominent achievement of high efficiency and greatly reduced efficiency roll-off.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, People's Republic of China.
authors.forename: Jiaxiu
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, People's Republic of China.
authors.forename: Jiangshan
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, People's Republic of China.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Qiao
authors.affiliation: Department of Chemistry, King Saud University , Riyadh, Kingdom of Saudi Arabia.
authors.forename: Saad M
authors.initials: SM
authors.lastname: Alshehri
authors.affiliation: Department of Chemistry, King Saud University , Riyadh, Kingdom of Saudi Arabia.
authors.forename: Tansir
authors.initials: T
authors.lastname: Ahamad
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, University of Chinese Academy of Sciences , Changchun 130022, People's Republic of China.|State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology , Guangzhou 510640, People's Republic of China.|Department of Chemistry, King Saud University , Riyadh, Kingdom of Saudi Arabia.
authors.forename: Dongge
authors.initials: D
authors.lastname: Ma
keywords: exciplex host; exciton density profile; quenching process; recombination zone; ultrathin layer