Materials, Structure Designs and Device Fabrications for Highly Efficient/Long Lifetime Organic Light-Emitting Diodes

Topic Information

Dear Colleagues,

Organic light-emitting diodes (OLEDs) constitute an excellent technology and have already been commercialized in full-color display panels due to their high efficiency and low manufacturing costs. Over the past two decades, tremendous efforts have been spent to improve the performance of OLEDs by measures such as developing efficient phosphorescent materials and TADF materials, or exploiting various device configurations to efficiently utilize excitons. Though the efficiency and lifetime of OLEDs have been made great progress, OLEDs still have a lot of issues to be solved before they can be widely used as lighting devices.

We expect that high-performance OLEDs which are highly efficient and/or highly reliable will be deveoped through the further exploration of the design of novel organic materials, new device structures and the underlying emission mechanisms. This Topic aims to cover recent developments in OLEDs. Contributions to this Topic can include full research articles, short communications, and reviews focusing on recent advancements in OLEDs.

Prof. Dr. Ping Chen
Prof. Dr. Jwo-Huei Jou
Topic Editors

Keywords

Participating Journals

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Chemistry chemistry	2.1	2.5	2019	19.1 Days	CHF 1800	Submit
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600	Submit
Micromachines micromachines	3.4	4.7	2010	16.1 Days	CHF 2600	Submit
Molecules molecules	4.6	6.7	1996	14.6 Days	CHF 2700	Submit
Photonics photonics	2.4	2.3	2014	15.5 Days	CHF 2400	Submit

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Published Papers (4 papers)

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15 pages, 12878 KiB  

Open AccessArticle

The Deposition and Properties of Titanium Films Prepared by High Power Pulsed Magnetron Sputtering

by Quanxin Jiang, Donglin Ma, Yantao Li and Changzi Chen

Materials 2023, 16(23), 7294; https://doi.org/10.3390/ma16237294 - 23 Nov 2023

Viewed by 635

Abstract

Titanium thin films are particularly important as electrode layers, barrier layers, or intermediate buffer layers in the semiconductor industry. In order to improve the quality of Ti thin films and the adhesion and diffraction abilities of irregular parts, this paper used high-power pulsed [...] Read more.

Titanium thin films are particularly important as electrode layers, barrier layers, or intermediate buffer layers in the semiconductor industry. In order to improve the quality of Ti thin films and the adhesion and diffraction abilities of irregular parts, this paper used high-power pulsed magnetron sputtering (HPPMS/HiPIMS) to prepare titanium thin films. The effects of different trigger voltages (700 V, 800 V, and 900 V) on plasma properties were studied, and the microstructure, mechanical properties and corrosion resistance of the films were also studied. The results showed that as the voltage increased, the grain size of the thin films gradually increased. The residual stress of the titanium films changed from compressive stress (−333 MPa) to tensile stress (55 MPa) and then to low compressive stress (−178 MPa). The hardness values were 13 GPa, 9.45 GPa and 6.62 GPa, respectively. The wear resistance of the films gradually decreased, while the toughness gradually increased. The corrosion resistance of the films decreased as well. Full article

(This article belongs to the Topic Materials, Structure Designs and Device Fabrications for Highly Efficient/Long Lifetime Organic Light-Emitting Diodes)

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10 pages, 9741 KiB  

Open AccessCommunication

Management of Exciton Distribution for High-Performance Organic Light-Emitting Diodes Based on Interfacial Exciplex Architecture

by Ren Sheng, Cong Chen, Erdong Zhang, Wencheng Zhao, Jihua Tang, Duxu Yan, Zhengze Li and Ping Chen

Molecules 2023, 28(20), 7028; https://doi.org/10.3390/molecules28207028 - 11 Oct 2023

Viewed by 768

Abstract

Interfacial exciplex has recently been adopted as an effective host to achieve phosphorescent organic light-emitting diodes (OLEDs) with high efficiencies and low driving voltages. However, a systematic understanding of exciton recombination behavior in either host of interfacial exciplex is still deficient. Herein, the [...] Read more.

Interfacial exciplex has recently been adopted as an effective host to achieve phosphorescent organic light-emitting diodes (OLEDs) with high efficiencies and low driving voltages. However, a systematic understanding of exciton recombination behavior in either host of interfacial exciplex is still deficient. Herein, the strategic design rule of interfacial exciplex host is proposed to overcome the negative effects of direct trapping recombination by systematically investigating exciton recombination behavior in interfacial exciplex hosts. As a result, blue and orange phosphorescent devices acquire peak external quantum efficiencies of 23.5% and 29.2% with low turn-on voltages. These results provide a simple method to realize highly efficient OLEDs aiming for general lighting and display applications. Full article

(This article belongs to the Topic Materials, Structure Designs and Device Fabrications for Highly Efficient/Long Lifetime Organic Light-Emitting Diodes)

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13 pages, 3314 KiB  

Open AccessArticle

The Equilibrium Molecular Structure of Cyclic (Alkyl)(Amino) Carbene Copper(I) Chloride via Gas-Phase Electron Diffraction and Quantum Chemical Calculations

by Alexander V. Belyakov, Ekaterina P. Altova, Anatoliy N. Rykov, Pavel Yu. Sharanov, Igor F. Shishkov and Alexander S. Romanov

Molecules 2023, 28(19), 6897; https://doi.org/10.3390/molecules28196897 - 01 Oct 2023

Cited by 1 | Viewed by 1237

Abstract

Copper-centered carbene–metal–halides (CMHs) with cyclic (alkyl)(amino) carbenes (CAACs) are bright phosphorescent emitters and key precursors in the synthesis of the highly promising class of the materials carbene–metal–amides (CMAs) operating via thermally activated delayed fluorescence (TADF). Aiming to reveal the molecular geometry for CMH [...] Read more.

Copper-centered carbene–metal–halides (CMHs) with cyclic (alkyl)(amino) carbenes (CAACs) are bright phosphorescent emitters and key precursors in the synthesis of the highly promising class of the materials carbene–metal–amides (CMAs) operating via thermally activated delayed fluorescence (TADF). Aiming to reveal the molecular geometry for CMH phosphors in the absence of the intermolecular contacts, we report here the equilibrium molecular structure of the (CAAC)Cu(I)Cl (1) molecule in the gas-phase. We demonstrate that linear geometry around a copper atom shows no distortions in the ground state. The structure of complex 1 has been determined using the electron diffraction method, supported by quantum chemical calculations with RI-MP2/def2-QZVPP level of theory and compared with the crystal structure determined by X-ray diffraction analysis. Mean vibrational amplitudes, u_ij,h1, and anharmonic vibrational corrections (r_ij,e • r_ij,a) were calculated for experimental temperature T = 20 °C, using quadratic and cubic force constants, respectively. The quantum theory of atoms in molecules (QTAIM) and natural bond order (NBO) analysis of wave function at MN15/def2TZVP level of theory revealed two Cu^…H, three H^…H, and one three-center H^…H^…H bond paths with bond critical points. NBO analysis also revealed three-center, four-electron hyperbonds, (3c4e), [π(N–C) n_π(Cu) ↔ n_π(N) π(N–Cu)], or [N–C: Cu ↔ N: C–Cu] and n_π(Cu) → π(C–N)* hyperconjugation, that is the delocalization of the lone electron pair of Cu atom into the antibonding orbital of C–N bond. Full article

(This article belongs to the Topic Materials, Structure Designs and Device Fabrications for Highly Efficient/Long Lifetime Organic Light-Emitting Diodes)

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15 pages, 2915 KiB  

Open AccessFeature PaperEditor’s ChoiceArticle

Simultaneous Hydrostatic and Compressive Loading System for Mimicking the Mechanical Environment of Living Cartilage Tissue

by Minki Chang, Yosuke Takahashi, Kyosuke Miyahira, Yuma Omuro, Kevin Montagne, Ryusei Yamada, Junki Gondo, Yu Kambe, Masashi Yasuno, Noriyasu Masumoto, Takashi Ushida and Katsuko S. Furukawa

Micromachines 2023, 14(8), 1632; https://doi.org/10.3390/mi14081632 - 18 Aug 2023

Viewed by 849

Abstract

In vivo, articular cartilage tissue is surrounded by a cartilage membrane, and hydrostatic pressure (HP) and compressive strain increase simultaneously with the compressive stress. However, it has been impossible to investigate the effects of simultaneous loading in vitro. In this study, a bioreactor [...] Read more.

In vivo, articular cartilage tissue is surrounded by a cartilage membrane, and hydrostatic pressure (HP) and compressive strain increase simultaneously with the compressive stress. However, it has been impossible to investigate the effects of simultaneous loading in vitro. In this study, a bioreactor capable of applying compressive stress under HP was developed to reproduce ex vivo the same physical loading environment found in cartilage. First, a HP stimulation unit was constructed to apply a cyclic HP pressure-resistant chamber by controlling a pump and valve. A compression-loading mechanism that can apply compressive stress using an electromagnetic force was implemented in the chamber. The synchronization between the compression and HP units was evaluated, and the stimulation parameters were quantitatively evaluated. Physiological HP and compressive strain were applied to the chondrocytes encapsulated in alginate and gelatin gels after applying high HP at 25 MPa, which induced damage to the chondrocytes. It was found that compressive stimulation increased the expression of genes related to osteoarthritis. Furthermore, the simultaneous application of compressive strain and HP, which is similar to the physiological environment in cartilage, had an inhibitory effect on the expression of genes related to osteoarthritis. HP alone also suppressed the expression of osteoarthritis-related genes. Therefore, the simultaneous hydrostatic and compressive stress-loading device developed to simulate the mechanical environment in vivo may be an important tool for elucidating the mechanisms of disease onset and homeostasis in cartilage. Full article

(This article belongs to the Topic Materials, Structure Designs and Device Fabrications for Highly Efficient/Long Lifetime Organic Light-Emitting Diodes)

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