title: High Brightness Fluorescent White Polymer Light-Emitting Diodes by Promoted Hole Injection via Reduced Barrier by Interfacial Dipole Imparted from Chlorinated Indium Tin Oxide to the Hole Injection Layer PEDOT:PSS.
abstract: We demonstrated that introducing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate as a hole transport layer (HTL) on top of chlorinated indium tin oxide (Cl-ITO) anode can lead to a deeper highest occupied molecular orbital level of the HTL (promoting from 5.22 to 5.42 eV) due to the interfacial dipole imparted by the Cl-ITO, which allows barrier-free hole injection to the emitting layer with polyspirobifluorene doped with the yellow emitter rubrene and significantly prevents excitons quenching by residual chlorine radicals on the surface of Cl-ITO. By use of poly[9,9-bis(6'-(18-crown-6)methoxy)hexyl)fluorene] chelating to potassium ion (PFCn6:K+) as electron injection layer and air-stable high work function (EΦ) metal aluminum as the cathode, the performance of fluorescent white polymer light-emitting diode (WPLED) achieves the high maximum brightness (Bmax) of 61 523 cd/m2and maximum luminance efficiency (ηL,max) of 10.3 cd/A. Replacing PFCn6:K+/Al cathode by CsF/Al, the Bmaxand ηL,maxare promoted to 87 615 cd/m2(the record value in WPLED) and 11.1 cd/A, respectively.
authors.affiliation: Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University , Hsinchu 30013, Taiwan, ROC.
authors.forename: Hong-Ren
authors.initials: HR
authors.lastname: Syue
authors.affiliation: Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University , Hsinchu 30013, Taiwan, ROC.
authors.forename: Miao-Ken
authors.initials: MK
authors.lastname: Hung
authors.affiliation: Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University , Hsinchu 30013, Taiwan, ROC.
authors.forename: Yao-Tang
authors.initials: YT
authors.lastname: Chang
authors.affiliation: Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University , Hsinchu 30013, Taiwan, ROC.
authors.forename: Ge-Wei
authors.initials: GW
authors.lastname: Lin
authors.affiliation: Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University , Hsinchu 30013, Taiwan, ROC.
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Chemical Engineering Department and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing-Hua University , Hsinchu 30013, Taiwan, ROC.
authors.forename: Show-An
authors.identifier: http://orcid.org/0000-0003-1133-8974
authors.initials: SA
authors.lastname: Chen
keywords: PEDOT:PSS; chlorinated-ITO (Cl-ITO); fluorescence; hole transport layer; interfacial dipole; polymer light-emitting diodes (PLED); polyspirobifluorene (PSBF)