High-performance tandem organic light-emitting diodes based on a buffer-modified p/n-type planar organic heterojunction as charge generation layer

Wu, Yukun; Sun, Ying; Qin, Houyun; Hu, Shoucheng; Wu, Qingwen; Zhao, Yi

doi:10.1007/s00339-017-0868-7

Cited by 7 publications

(4 citation statements)

References 29 publications

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“…In the recent years, -conjugated organic molecules have been the subject of increasing attention due to their unique electrical and optical properties, which make them suitable active materials for photovoltaic cells [1], photodiodes [2,3], and molecular sensors [4][5][6][7], among other optoelectronic devices [8][9][10][11]. The oligo-p-terphenylenes are of particular interest because the smallest (terphenyl, quaterphenyl, and quinquephenyl) are able to not only radiate a high energy light in the blue region of the spectrum but also display a rich thermotropic polymorphism.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Study of Chemical, Thermal, Mesomorphic, and Optical Properties of Terphenyls Modified with Nitrile Groups

González

Carrillo-Castillo

Ambrosio

et al. 2017

Journal of Chemistry

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We report the synthesis, characterization, and the thermotropic and photoluminescence properties of dialkoxyterphenyls with (T12-CN and T12-2CN) and without (T12) nitrile groups. These terphenyls were prepared through the Suzuki-Miyaura crosscoupling reaction using a palladium-based catalyst. The products obtained were analyzed as powders or after being drop-casted or spin-coated on glass. Nuclear Magnetic Resonance ( 1 H NMR) and Fourier Transform Infrared (FTIR) spectroscopy techniques confirmed the structure and purity of the synthesized terphenyls. The mesomorphic behavior was studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). T12 developed various mesophases, whereas T12-CN and T12-2CN displayed one single mesophase of low order over a wide temperature range. The films topology was studied by AFM and the optical properties were determined by ultraviolet-visible (UV-Vis) spectroscopy and spectrofluorometry. Higher roughness was found for the films prepared with the asymmetric terphenyl (T12-CN). The photoluminescence (PL) spectrum obtained for the asymmetric terphenyl (T12-CN) exhibited the expected characteristics with an emission band centered at 381 nm and an overtone around 760 nm.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Study of Chemical, Thermal, Mesomorphic, and Optical Properties of Terphenyls Modified with Nitrile Groups

González

Carrillo-Castillo

Ambrosio

et al. 2017

Journal of Chemistry

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“…5,21) An efficient CGU with good charge generation and separation abilities is vital for a high-performance tandem device. [9][10][11][12] We have demonstrated that the multilayer structure CGU of LiF/Al/C 60 /ZnPc/MoO 3 possesses excellent charge generation, separation and injection capabilities when the ETL of TPBi and the HTL of NPB were used. 22) Since the LUMOs of TPBi and TmPyPB are −2.7 eV and the HOMO difference between NPB and TAPC is only 0.1 eV, the CGU also possesses excellent charge generation abilities when the ETL and HTL are TmPyPB and TAPC, respectively.…”

mentioning

confidence: 96%

“…The tandem PhOLED can realize a significant enhancement in both efficiency and stability by decreasing the current density within the overall device. 9,11,12) For example, Forrest and co-workers 13) and Kido and co-workers 14) have obtained high-performance tandem blue PhOLEDs (T-BPhOLEDs). Thus, the tandem structure potentially provides a key solution for realizing high-performance BPhOLEDs.…”

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confidence: 99%

Highly efficient tandem blue phosphorescent organic LEDs with external quantum efficiency exceeding 42%

Ai¹,

Wang²,

Xie³

et al. 2020

Appl. Phys. Express

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High-performance tandem blue phosphorescent organic LEDs (T-BPhOLEDs) are important for solid-state lighting and flat-panel display. Herein, we have realized a highly efficient T-BPhOLED by using the photovoltaic-type charge generation unit (CGU) of LiF/Al/fullerene/zinc-phthalocyanine/MoO3, blue phosphorescent emitter of bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) and electron transporter of 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene. The charge generation ability of CGU could be enhanced by the photovoltaic function of fullerene/zinc-phthalocyanine in T-BPhOLEDs. Under high luminance, a cycle composed of the CGU and emission layers in T-BPhOLEDs could convert some of the internal radiation into external radiation for improving performance. Simultaneously, the optimal T-BPhOLED exhibits a high external quantum efficiency of 42.9% at 100 cd·m−2.

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“…1) A T-PhOLED combines two or more individual electroluminescent (EL) units in series through a charge generation unit (CGU). 2,3) Under an applied external bias, the electrons and holes are generated within CGU, and injected into the adjacent charge transport layers of the individual EL units. 4) Obviously, CGU plays an important role in T-PhOLEDs.…”

mentioning

confidence: 99%

Remarkable enhancement of efficiencies for red, green, and blue tandem phosphorescent organic light-emitting diodes by utilizing a non-doped photovoltaic-type charge generation unit

Ai¹,

Wang²,

Xie³

et al. 2019

Jpn. J. Appl. Phys.

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We have achieved a remarkable enhancement in current efficiencies and power efficiencies for red, green, and blue tandem phosphorescent organic LEDs (T-PhOLEDs) by employing LiF/Al/fullerene/zinc-phthalocyanine/MoO 3 as a charge generation unit (CGU). Fullerene/zincphthalocyanine with a proper absorption property in the visible region can absorb a part of photons from emission layers within T-PhOLEDs, which facilitates the charge generation and separation within CGU. At the identical luminance of 1,000 cd m −2 , the current efficiencies for red, green, and blue T-PhOLEDs are 3.3-, 2.1-, and 2.9-fold those of the corresponding single-unit devices, and power efficiencies are increased by 72.2%, 13.6%, and 37.2%, respectively. © 2019 The Japan Society of Applied Physics C 60 (5 nm)/ZnPc(5 nm) exhibits the highest transmittance level over the entire visible range. Additionally, the efficient charge generation and separation within the CGU are vital for T-PhOLEDs. For studying the charge generation and separation processes of the CGU, a

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High-performance tandem organic light-emitting diodes based on a buffer-modified p/n-type planar organic heterojunction as charge generation layer

Cited by 7 publications

References 29 publications

Synthesis and Study of Chemical, Thermal, Mesomorphic, and Optical Properties of Terphenyls Modified with Nitrile Groups

Synthesis and Study of Chemical, Thermal, Mesomorphic, and Optical Properties of Terphenyls Modified with Nitrile Groups

Highly efficient tandem blue phosphorescent organic LEDs with external quantum efficiency exceeding 42%

Remarkable enhancement of efficiencies for red, green, and blue tandem phosphorescent organic light-emitting diodes by utilizing a non-doped photovoltaic-type charge generation unit

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