Performance improvement of blue TADF top-emission OLEDs by tuning hole injection barriers using a nickel-doped silicon dioxide buffer layer

Ren, Wanqi; Son, Kyung Rock; Kim, Tae Geun

doi:10.1016/j.apsusc.2022.155948

Cited by 6 publications

(1 citation statement)

References 52 publications

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“…While the IQE of TADF OLEDs can theoretically reach 100%, the external quantum efficiency (EQE) struggles to exceed 20%. − This limitation is attributed to several modes, such as substrate mode and waveguide mode, resulting from refractive index differences between the interfaces within the OLED and surface plasmon polariton modes generated at the interface between the metal and organic layers. − Various structural solutions have been proposed to address these issues and analyze the improvement in OLED performance, such as tuning the thickness or material of the layers ,− and the incorporation of light extraction layers, such as nanostructured materials or microlens arrays (MLAs). ,− Given the stability and efficiency challenges associated with blue TADF organic materials, studies on light extraction structures applicable to blue TADF OLEDs hold significant value.…”

Section: Introductionmentioning

confidence: 99%

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si₃N₄ Nanofiber Structure

Park,

Lee,

et al. 2024

ACS Appl. Mater. Interfaces

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We selectively improved the viewing angle characteristics and light extraction efficiency of blue thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) by tailoring a nanofiber-shaped Si3N4 layer, which was used as an internal scattering layer. The diameter of the polymer nanofibers changed according to the mass ratio of polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA) in the polymer solution for electrospinning. The Si3N4 nanofiber (SNF) structure was fabricated by etching an Si3N4 film using the PAN/PMMA nanofiber as a mask, making it easier to adjust parameters, such as the diameter, open ratio, and height, even though the SNF structure was randomly shaped. The SNF structures exhibited lower transmittance and higher haze with increasing diameter, showing little correlation with their height. However, all the structures demonstrated a total transmittance of over 80%. Finally, by applying the SNF structures to the blue TADF OLEDs, the external quantum efficiency was increased by 15.6%. In addition, the current and power efficiencies were enhanced by 23.0% and 25.6%, respectively. The internal light-extracting SNF structure also exhibited a synergistic effect with the external light-extracting structure. Furthermore, when the viewing angle changed from 0° to 60°, the peak wavelength and CIE coordinate shift decreased from 20 to 6 nm and from 0.0561 to 0.0243, respectively. These trends were explained by the application of Snell’s law to the light path and were ultimately validated through finite-difference time-domain simulations.

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Section: Introductionmentioning

confidence: 99%

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si₃N₄ Nanofiber Structure

Park,

Lee,

et al. 2024

ACS Appl. Mater. Interfaces

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Enhancing Narrowband Blue TADF OLED Performance with Adamantane Group‐Integrated Spatially Hindered 1,3‐Bis(N‐Carbazolyl)Benzene‐Based Host

Kim,

Kang,

Lee

et al. 2024

Adv Funct Materials

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In the past, considerable effort are focused on advancing blue organic light‐emitting diodes (OLEDs) based on 1,3‐bis(N‐carbazolyl)benzene (mCP). To enhance and stabilize the device performance in vacuum‐processed OLEDs, it is essential to optimize the thermally stable organic materials constituting the emitting layer. The proposed novel carbazole derivative, Ad‐mCP, is designed and synthesized as a host material for blue thermally activated delayed fluorescence OLEDs, which are ideal for vacuum processing. Ad‐mCP exhibits a high glass transition temperature and triplet energy (T1), making it highly compatible with the blue dopant 2,11,14‐tri‐tert‐butyl‐N,N,5‐tris(4‐(tert‐butyl)phenyl)−5H‐5,8b‐diaza‐15b‐borabenzo[a]naphtho[1,2,3‐hi]aceanthrylen‐7‐amine emitter. The incorporation of a rigid adamantane unit into the carbazole group modifies the molecular structure of mCP, preserving crucial photophysical properties, such as T1,while enhancing the morphological and thermal stability of the host material in its film state. Moreover, the spatially hindered molecular structure of Ad‐mCP improves the photoluminescent quantum yield of the emissive layer and enhances charge balance, crucially contributing to the overall efficiency of the OLEDs. As a result, the exceptional performance of Ad‐mCP as a host material for OLEDs resulted in a remarkably high maximum external quantum efficiency of 29.9%, demonstrating superior stability in efficiency even after thermal annealing compared to mCP devices.

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All solution-processed blue OLEDs with a difluoroboron compound in the emissive layer and non-evaporated cathode

Alvarez-Quesada,

González-García,

Ramos-Ortiz

et al. 2025

Optical Materials

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Performance improvement of blue TADF top-emission OLEDs by tuning hole injection barriers using a nickel-doped silicon dioxide buffer layer

Cited by 6 publications

References 52 publications

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si₃N₄ Nanofiber Structure

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si₃N₄ Nanofiber Structure

Enhancing Narrowband Blue TADF OLED Performance with Adamantane Group‐Integrated Spatially Hindered 1,3‐Bis(N‐Carbazolyl)Benzene‐Based Host

All solution-processed blue OLEDs with a difluoroboron compound in the emissive layer and non-evaporated cathode

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Performance improvement of blue TADF top-emission OLEDs by tuning hole injection barriers using a nickel-doped silicon dioxide buffer layer

Cited by 6 publications

References 52 publications

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si3N4 Nanofiber Structure

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si3N4 Nanofiber Structure

Enhancing Narrowband Blue TADF OLED Performance with Adamantane Group‐Integrated Spatially Hindered 1,3‐Bis(N‐Carbazolyl)Benzene‐Based Host

All solution-processed blue OLEDs with a difluoroboron compound in the emissive layer and non-evaporated cathode

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Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si₃N₄ Nanofiber Structure

Selective Enhancement of Viewing Angle Characteristics and Light Extraction Efficiency of Blue Thermally Activated Delayed Fluorescence Organic Light-Emitting Diodes through an Easily Tailorable Si₃N₄ Nanofiber Structure