Dependence of Light-Emitting Characteristics of Blue Phosphorescent Organic Light-Emitting Diodes on Electron Injection and Transport Materials

Abstract

We investigate the light‐emitting performances of blue phosphorescent organic light‐emitting diodes (PHOLEDs) with three different electron injection and transport materials, that is, bathocuproine(2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline) (Bphen), 1,3,5‐tri(m‐pyrid‐3‐yl‐phenyl)benzene (Tm3PyPB), and 2,6‐bis(3‐(carbazol‐9‐yl)phenyl)pyridine (26DCzPPy), which are partially doped with cesium metal. We find that the device characteristics are very dependent on the nature of the introduced electron injection layer (EIL) and electron transporting layer (ETL). When the appropriate EIL and ETL are combined, the peak external quantum efficiency and peak power efficiency improve up to 20.7% and 45.6 lm/W, respectively. Moreover, this blue PHOLED even maintains high external quantum efficiency of 19.6% and 16.9% at a luminance of 1,000 cd/m2 and 10,000 cd/m2, respectively.

52.1: Invited Paper: Highly Efficient Transparent Organic Light Emitting Diodes with an Internal Random Nano‐structured Scattering Layer

“…In this work we have used a green and an white OLEDs. Here, based on the results of our previous reports [11,12], we introduced TAPC of 120nm as a capping layer(CL) on the Ag cathode to maximize total efficiency by enhancing reflectance of the cathode. The preparation of the RSL scattering layer has been previously reported [13,14].…”

Surface Control of Planarization Layer on Embossed Glass for Light Extraction in OLEDs

“…Since Tang and VanSlyke reported the first practical organic light-emitting diodes (OLEDs) in 1987, this field has attracted significant attention from the scientific and commercial communities [1]. Highly efficient white OLEDs are becoming more important for their potential application to flat panel displays and lighting [2]- [3]. In recent years, light extraction of white OLEDs has attracted great attention as a realization method for OLED panels with high external luminous efficacy.…”

Enhanced and balanced efficiency of white bi-directional organic light-emitting diodes

“…A 10-nm-thick film of TAPC and a 10-nmthick film of SPPO1 were used as electron and hole blocking layers, respectively, to confine charge carriers and excitons within the EML. Two blue-emitting EMLs, one containing 7 wt% blue light-emitting iridium(III)bis(4,6-difluorophenyl)-pyridinato-N,C 2' )picolinate (FIrpic) co-deposited with the hole-transport type host material 4,4',4"-tri(Ncarbazolyl)triphenylamine (TCTA, 5 nm) and another containing 10 wt% FIrpic co-deposited with the bipolar type host material 2,6-bis(3-(carbazol-9-yl)phenyl)pyridine (26DCzPPy, 5 nm), were successively deposited [12,13]. Two types of white BiOLEDs were fabricated: Device A was based on a 2-color white approach, a 1-nm-thick layer of TCTA doped with 6 wt% of the red emitter iridium (III) bis[2-methyldibenzo-(f,h)quinoxaline](acetylacetonate) (Ir(MDQ) 2 (acac)) was inserted between the two blue EMLs.…”