Silane- and triazine-containing hole and exciton blocking material for high-efficiency phosphorescent organic light emitting diodes

Kang, Jae‐Wook; Lee, Deug Sang; Park, Hyung Dol; Park, Young-Seo; Kim, Ji Whan; Jeong, Won Ik; Yoo, Kyung; Go, Kyoungmoon; Kim, Se Hoon; Kim, Jang‐Joo

doi:10.1039/b705741e

Cited by 79 publications

(22 citation statements)

References 20 publications

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“…On the contrary, no injection barrier was observed for hole injection from NPB into the layer of yellow phosphor Y‐Pt doped TCTA in the B/B/Y device due to direct injection/charge trap (further explained in Section 2.5), as shown in Figure 2c. In addition, BAlq with μ e higher than that for TAZ ( μ e = 3.1 × 10 −5 cm 2 V −1 s −1 29 for BAlq and 1.3 × 10 −5 cm 2 V −1 s −1 30 for TAZ at the same electric field of 1.0 MV cm −1 ) contributes to a lower driving voltage observed with the modified WOLEDs.…”

Section: Resultsmentioning

confidence: 90%

High Efficiency White Organic Light‐Emitting Devices Incorporating Yellow Phosphorescent Platinum(II) Complex and Composite Blue Host

Lai

Tong

Kui

et al. 2013

Adv Funct Materials

104

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A new class of charge neutral, strongly luminescent cyclometalated platinum(II) complexes supported by dianionic tetradentate ligand are synthesized. One of these platinum(II) complexes, Y‐Pt, displays a high photoluminescence quantum yield of 86% and electroluminescence efficacy (ηpower) of up to 52 lm W−1, and is utilized as a yellow phosphorescent dopant in the fabrication of white organic light‐emitting devices (WOLEDs). WOLEDs based on conventional structures with yellow emission from Y‐Pt in combination with blue emission from bis(4,6‐difluorophenyl‐pyridinato‐N,C2′) (picolinate) iridium(III) (FIrpic) show a total ηpower of up to 31 lm W−1. A two‐fold increase in ηpower by utilizing a modified WOLED structure comprising of a composite blue host is realized. With this modified device structure, the total ηpower and driving voltage at a luminance of 1000 cd m−2 can be improved to 61 lm W−1 and 7.5 V (i.e., 10 V for control devices). The performance improvement is attributed to an effectively broaden exciton formation‐recombination zone and alleviation of localized exciton accumulation within the FIrpic‐doped composite host for reduced triplet‐triplet annihilation, yielding blue light‐emission with enhanced intensity. The modified device structure can also adopt a higher concentration of Y‐Pt towards its optimal value, leading to WOLEDs with high efficiency.

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Section: Resultsmentioning

confidence: 90%

High Efficiency White Organic Light‐Emitting Devices Incorporating Yellow Phosphorescent Platinum(II) Complex and Composite Blue Host

Lai

Tong

Kui

et al. 2013

Adv Funct Materials

104

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“…However, the performances of DSX-LPP-based device B are nevertheless better than those of device A because NPB avoids the quenching of the holes near the anode. Finally, to prevent holes from crossing the device and reaching the cathode without recombination, a hole blocking layer (HBL) of bathocuproine (BCP, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) with a HOMO level of À6.4 eV [18,90,91] has been added (devices D).…”

Section: Oleds With Dsx-lpp and Dsx-if As Emitting Layersmentioning

confidence: 99%

Incorporation of Spiroxanthene Units in Blue‐Emitting Oligophenylene Frameworks: A New Molecular Design for OLED Applications

Poriel

Cocherel

Rault‐Berthelot

et al. 2011

Chemistry A European J

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We report herein the incorporation of xanthenyl units into two extended π-conjugated phenylene systems, namely indenofluorene and pentaphenylene. Thus, dispiroxanthene-indenofluorene (DSX-IF) and dispiroxanthene-ladderpentaphenylene (DSX-LPP) have been designed and synthesized through short and efficient synthetic approaches. These two molecules possess a 3π-2-spiro architecture (3π-systems/2-spiro bridges), in which two xanthenyl cores are spirolinked to a π-conjugated backbone either indenofluorene for DSX-IF or pentaphenylene for DSX-LPP. The structural, electrochemical, and photophysical properties of these blue/violet emitters have been studied in detail and compared to those of their 'all carbon' analogues with spirofluorenyl cores instead of spiroxanthenyl cores, namely dispirofluorene-indenofluorene (DSF-IF) and dispirofluorene-ladderpentaphenylene (DSF-LPP), previously reported in the literature. Finally, the application of DSX-IF and DSX-LPP as new light-emitting materials in nondoped organic light emitting diodes is reported. A detailed optical study of the different electroluminescence spectra is notably presented, with an emphasis 1) on the origin of the low-energy emission band observed in the case of DSX-LPP and 2) on the unexpected optical contribution of the well-known hole-transporting-layer NPB (N,N'-di(naphtyl)-N,N'-diphenyl(1,1'-biphenyl)-4,4'-diamine).

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“…2,13,19 Although multiple HILs are applied to match the energy level of ITO and deep-blue emitters to improve the hole injection, the big HOMO energy level gap among HILs, e.g., PEDOT:PSS and PVK, is still difficult to overcome to maximize the performance of deep-blue emitters. 20 The electron-deficient 1,3,5-triazine derivatives have been widely used as electron transport materials, [21][22][23] hole transport materials 24 and bipolar transport materials. 25 However, there is no report on hole injection materials based on electron-deficient 1,3,5-triazine and electron-rich compounds such as phenol and its derivatives with preferred solution processing ability.…”

Section: Introductionmentioning

confidence: 99%

Highly Improved Efficiency of Deep-Blue Fluorescent Polymer Light-Emitting Device Based on a Novel Hole Interface Modifier with 1,3,5-Triazine Core

Xia

Xue

Xiong

et al. 2015

ACS Appl. Mater. Interfaces

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We present an investigation of deep-blue fluorescent polymer light-emitting diodes (PLEDs) with a novel functional 1,3,5-triazine core material (HQTZ) sandwiched between poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic acid) layer and poly(vinylcarbazole) layer as a hole injection layer (HIL) without interface intermixing. Ultraviolet photoemission spectroscopy and Kelvin probe measurements were carried out to determine the change of anode work function influenced by the HQTZ modifier. The thin HQTZ layer can efficiently maximize the charge injection from anode to blue emitter and simultaneously enhance the hole mobility of HILs. The deep-blue device performance is remarkably improved with the maximum luminous efficiency of 4.50 cd/A enhanced by 80% and the maximum quantum efficiency of 4.93%, which is 1.8-fold higher than that of the conventional device without HQTZ layer, including a lower turn-on voltage of 3.7 V and comparable Commission Internationale de L'Eclairage coordinates of (0.16, 0.09). It is the highest efficiency ever reported to date for solution-processed deep-blue PLEDs based on the device structure of ITO/HILs/poly(9,9-dialkoxyphenyl-2,7-silafluorene)/CsF/AL. The results indicate that HQTZ based on 1,3,5-triazine core can be a promising candidate of interfacial materials for deep-blue fluorescent PLEDs.

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Silane- and triazine-containing hole and exciton blocking material for high-efficiency phosphorescent organic light emitting diodes

Cited by 79 publications

References 20 publications

High Efficiency White Organic Light‐Emitting Devices Incorporating Yellow Phosphorescent Platinum(II) Complex and Composite Blue Host

High Efficiency White Organic Light‐Emitting Devices Incorporating Yellow Phosphorescent Platinum(II) Complex and Composite Blue Host

Incorporation of Spiroxanthene Units in Blue‐Emitting Oligophenylene Frameworks: A New Molecular Design for OLED Applications

Highly Improved Efficiency of Deep-Blue Fluorescent Polymer Light-Emitting Device Based on a Novel Hole Interface Modifier with 1,3,5-Triazine Core

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