Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (148)

Search Parameters:
Keywords = blue organic light-emitting diodes

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
13 pages, 1661 KiB  
Communication
Effects of Long-Term Blue Light Exposure on Body Fat Synthesis and Body Weight Gain in Mice and the Inhibitory Effect of Tranexamic Acid
by Keiichi Hiramoto and Hirotaka Oikawa
Int. J. Mol. Sci. 2025, 26(12), 5554; https://doi.org/10.3390/ijms26125554 - 10 Jun 2025
Viewed by 681
Abstract
Humans are continuously exposed to blue light from sunlight, computers, and smartphones. While blue light has been reported to affect living organisms, its role in fat synthesis and weight changes remains unclear. In this study, we investigated the effects of prolonged blue light [...] Read more.
Humans are continuously exposed to blue light from sunlight, computers, and smartphones. While blue light has been reported to affect living organisms, its role in fat synthesis and weight changes remains unclear. In this study, we investigated the effects of prolonged blue light exposure on weight changes in mice and the protective role of tranexamic acid (TA). Mice were exposed daily to blue light from a light-emitting diode for five months. Blue light exposure led to increased fat mass and body weight. The expression of the clock genes arnt-like 1 (Bmal1) and Clock was reduced in the brain and muscle of exposed mice. In addition, reduced Sirt1 and increased mammalian target of rapamycin complex 1 (mTORC1)/sterol regulatory element-binding protein 1 (SREBP1) were observed. The levels of liver X receptor a and liver kinase B1/5′AMP-activated protein kinase a1, both involved in SREBP1-mediated lipogenesis, were also elevated. TA treatment prevented the blue light-induced suppression of Bmal1/Clock and modulated the subsequent series of signal transduction. These findings suggest that prolonged blue light exposure suppresses the clock gene Bmal1/Clock, reduces Sirt1, and activates lipogenic pathways, contributing to weight gain. TA appears to regulate clock gene expression and mitigate blue light-induced weight gain. Full article
(This article belongs to the Section Biochemistry)
Show Figures

Figure 1

13 pages, 3616 KiB  
Article
Synthesis, Structure, and Luminescence Properties of Zinc(II) Complex with a Spacer-Armed Tetradentate N2O2-Donor Schiff Base
by Alexey Gusev, Elena Braga, Kirill Mamontov, Mikhail Kiskin and Wolfgang Linert
Inorganics 2025, 13(5), 173; https://doi.org/10.3390/inorganics13050173 - 19 May 2025
Viewed by 661
Abstract
A zinc complex bearing a pyrazolone-based azomethine ligand has been synthesized for blue-emitting organic light-emitting diodes (OLEDs). The azomethine ligand H2L and the complex [ZnL·H2O] were characterized by IR, 1H NMR, XRD, and TGA/DSC techniques. According to a single-crystal [...] Read more.
A zinc complex bearing a pyrazolone-based azomethine ligand has been synthesized for blue-emitting organic light-emitting diodes (OLEDs). The azomethine ligand H2L and the complex [ZnL·H2O] were characterized by IR, 1H NMR, XRD, and TGA/DSC techniques. According to a single-crystal X-ray diffraction analysis, the complex [ZnL·H2O] has a molecular structure. Its solid-state PL maxima appear to be at 416 nm and emit moderate blue emission with a quantum yield (QY) of 2%, with a dehydrated form of the complex showing greater efficiency with a QY of 55.5%. ZnL-based electroluminescent devices for OLED applications were fabricated. The devices exhibit blue emission with brightness up to 5300 Cd/A. Full article
(This article belongs to the Section Coordination Chemistry)
Show Figures

Graphical abstract

13 pages, 2117 KiB  
Article
High-Efficiency Deep-Blue Solution-Processed OLED Devices Enabled by New Dopant Materials
by Saeyoung Oh, Hyukmin Kwon, Sangwook Park, Seokwoo Kang, Sang-Tae Kim, Kiho Lee, Hayoon Lee and Jongwook Park
Materials 2025, 18(10), 2213; https://doi.org/10.3390/ma18102213 - 10 May 2025
Cited by 1 | Viewed by 736
Abstract
Two blue fluorescent dopants were designed and successfully synthesized, 5-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho [3,2,1-de]anthracen-7-yl)-5H-benzo[b]carbazole (TDBA-Bz) and 9-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-9H-carbazole (TDBA-Cz). Both in solution and the film state, the two emitters demonstrated deep-blue luminescence characteristics. In solution-processed organic light-emitting diodes (OLEDs), TDBA-Bz and TDBA-Cz used as dopant materials showed [...] Read more.
Two blue fluorescent dopants were designed and successfully synthesized, 5-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho [3,2,1-de]anthracen-7-yl)-5H-benzo[b]carbazole (TDBA-Bz) and 9-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-9H-carbazole (TDBA-Cz). Both in solution and the film state, the two emitters demonstrated deep-blue luminescence characteristics. In solution-processed organic light-emitting diodes (OLEDs), TDBA-Bz and TDBA-Cz used as dopant materials showed electroluminescence peaks at 436 nm and 413 nm, respectively. The corresponding CIE color coordinates were determined to be (0.181, 0.114) for TDBA-Bz and (0.167, 0.086) for TDBA-Cz. The solution-processed device using TDBA-Cz as a dopant exhibited a current efficiency (CE) of 7.25 cd/A and an external quantum efficiency (EQE) of 6.45%, demonstrating higher efficiencies compared to the device with TDBA-Bz. In particular, at a luminance of 2000 cd/m2, TDBA-Cz maintained an EQE of 4.81%, with only a slight decrease from its maximum EQE. Full article
Show Figures

Figure 1

27 pages, 7917 KiB  
Review
Blue Exciplexes in Organic Light-Emitting Diodes: Opportunities and Challenges
by Duxu Yan, Mengmeng Zhang, Jintao Wang, Xiaoqing Jing, Jun Sun, Yongan Zhang, Liping Yang, Ren Sheng and Ping Chen
Molecules 2025, 30(7), 1556; https://doi.org/10.3390/molecules30071556 - 31 Mar 2025
Viewed by 1090
Abstract
Blue exciplexes, a critical innovative component in organic light-emitting diodes (OLEDs) technology, exhibit substantial potential for enhancing device efficiency, reducing driving voltage, and simplifying structural designs. This article reviews the pivotal role of blue exciplexes in OLEDs, analyzing their unique advantages and challenges [...] Read more.
Blue exciplexes, a critical innovative component in organic light-emitting diodes (OLEDs) technology, exhibit substantial potential for enhancing device efficiency, reducing driving voltage, and simplifying structural designs. This article reviews the pivotal role of blue exciplexes in OLEDs, analyzing their unique advantages and challenges as emitters and host materials. Through optimized molecular design, blue exciplexes achieve high color purity and emission efficiency, surpassing conventional fluorescent materials. Additionally, their wide energy bands and high triplet energy provide opportunities to improve the performance of sky-blue, deep-blue, and white OLEDs. However, limitations in deep-blue efficiency, material degradation due to high-energy excitons, and spectral red-shift pose significant challenges to their development. This review offers a comprehensive perspective and research reference on the photophysical mechanisms of blue exciplexes and their applications in display and lighting fields. Full article
(This article belongs to the Special Issue Opportunities and Challenges in Organic Optoelectronic Materials)
Show Figures

Figure 1

16 pages, 7712 KiB  
Article
Impact of KOH Wet Treatment on the Electrical and Optical Characteristics of GaN-Based Red μLEDs
by Shuhan Zhang, Yun Zhang, Hongyu Qin, Qian Fan, Xianfeng Ni, Li Tao and Xing Gu
Crystals 2025, 15(4), 288; https://doi.org/10.3390/cryst15040288 - 22 Mar 2025
Viewed by 465
Abstract
Micro-size light-emitting diodes (μLEDs) are high-brightness, low-power optoelectronic devices with significant potential in display technology, lighting, and biomedical applications. AlGaInP-based red LEDs experience severe size-dependent effects when scaled to the micron level, and addressing the fabrication challenges of GaN-based red μLED arrays is [...] Read more.
Micro-size light-emitting diodes (μLEDs) are high-brightness, low-power optoelectronic devices with significant potential in display technology, lighting, and biomedical applications. AlGaInP-based red LEDs experience severe size-dependent effects when scaled to the micron level, and addressing the fabrication challenges of GaN-based red μLED arrays is crucial for achieving homogeneous integration. This study investigates the employment of KOH wet treatments to alleviate efficiency degradation caused by sidewall leakage currents. GaN-based red μLED arrays with pixel sizes ranging from 5 × 5 µm2 to 20 × 20 µm2 were grown using metal-organic chemical vapor deposition (MOCVD), and then fabricated via rapid thermal annealing, mesa etching, sidewall wet treatment, electrode deposition, sidewall passivation, chemical-mechanical polishing, and via processes. The arrays, with pixel densities ranging from 668 PPI (Pixel Per Inch) to 1336 PPI, consist of 10,000 to 40,000 emitting pixels, and their optoelectronic properties were systematically evaluated. The arrays with varying pixel sizes fabricated in this study were subjected to three distinct processing conditions: without KOH treatment, 3 min of KOH treatment, and 5 min of KOH treatment. Electrical characterization reveals that the 5-min KOH treatment significantly reduces leakage current, enhancing the electrical performance, as compared to the samples without KOH treatment or 3-min treatment. In terms of optical properties, while the arrays without any KOH treatment failed to emit light, the ones with 3- and 5-min KOH treatment exhibit excellent optical uniformity and negligible blue shift. Most arrays treated for 5 min demonstrate superior light output power (LOP) and optoelectronic efficiency, with the 5 µm pixel arrays exhibiting unexpectedly high performance. The results suggest that extending the KOH wet treatment time effectively mitigates sidewall defects, reduces non-radiative recombination, and enhances surface roughness, thereby minimizing optical losses. These findings provide valuable insights for optimizing the fabrication of high-performance GaN-based red μLEDs and contribute to the development of stable, high-quality small-pixel μLEDs for advanced display and lighting applications. Full article
Show Figures

Figure 1

34 pages, 10137 KiB  
Review
Progress in Luminescent Materials Based on Europium(III) Complexes of β-Diketones and Organic Carboxylic Acids
by Qianting Chen, Jie Zhang, Quanfeng Ye, Shanqi Qin, Lingyi Li, Mingyu Teng and Wai-Yeung Wong
Molecules 2025, 30(6), 1342; https://doi.org/10.3390/molecules30061342 - 17 Mar 2025
Cited by 2 | Viewed by 1554
Abstract
Europium(III) β-diketone and organic carboxylic acid complexes are designable, easy to prepare, and easy to modify and have excellent fluorescence properties (narrow emission spectral band, high colour purity, long fluorescence lifetime, high quantum yield, and a spectral emission range covering both the visible [...] Read more.
Europium(III) β-diketone and organic carboxylic acid complexes are designable, easy to prepare, and easy to modify and have excellent fluorescence properties (narrow emission spectral band, high colour purity, long fluorescence lifetime, high quantum yield, and a spectral emission range covering both the visible and near-infrared regions). These complexes play important roles in popular fields such as laser and fibre-optic communications, medical diagnostics, immunoassays, fluorescent lasers, sensors, anticounterfeiting, and organic light-emitting diodes (OLEDs). In the field of light-emitting materials, europium complexes are especially widely used in OLED lamps, especially because of their high-efficiency emission of red (among the three primary colours); accordingly, these complexes can be mixed with blue and green phosphors to obtain high-efficiency white phosphors that can be excited by near-ultraviolet light. This paper reviews the red-light-emitting europium complexes with β-diketone and organic carboxylic acid as ligands that have been studied over the last five years, describes the current problems, and discusses their future application prospects. Full article
Show Figures

Figure 1

13 pages, 6535 KiB  
Article
An Eight-Membered Ring Molecular Framework Based on Carbazole for the Development of Electroluminescent Materials
by An Yan, Shipan Xu, Xuyang Du, Chengyun Zhu, Shengli Li, Xiaolong Yang, Guijiang Zhou and Yuanhui Sun
Molecules 2025, 30(3), 716; https://doi.org/10.3390/molecules30030716 - 5 Feb 2025
Viewed by 941
Abstract
The organic light-emitting diode (OLED) has been regarded as the most prominent product in the current market of organic electronics, which has attracted growing attention because of their applications in full-color displays and solid-state lighting. Organic materials that exhibit strong luminescence in the [...] Read more.
The organic light-emitting diode (OLED) has been regarded as the most prominent product in the current market of organic electronics, which has attracted growing attention because of their applications in full-color displays and solid-state lighting. Organic materials that exhibit strong luminescence in the solid state constitute the core position of OLED. Extensive research efforts to probe the structure of organic luminescent materials have attracted considerable attention to the conjugated fusion ring architecture. This is because it can confer molecular rigidity and helps to inhibit intermolecular interactions and non-radiative transitions, thus enhancing the performance of luminescent materials. Here, we use an efficient and simple method to construct an eight-membered ring molecular framework based on carbazole. Moreover, we have introduced groups with different electron-withdrawing abilities to develop a series of luminescent molecules. The results show that the nonplanar structure based on the eight-membered ring suppresses fluorescence quenching caused by molecular aggregation. As the doping concentration increases, the electroluminescence spectrum remains basically unchanged, indicating that the eight-membered ring structure can effectively suppress the intermolecular interaction. Notably, DCBz-pm exhibits deep blue emission with a Commission Internationale de l’Eclairage (CIE) coordinate of (0.158, 0.046), which nearly meets the BT. 2020 standards. The DCBz-CN device reaches a maximum external quantum efficiency (EQE) of 4.36%. These results offer a new design strategy for improving the performance of OLEDs. Full article
Show Figures

Graphical abstract

13 pages, 2818 KiB  
Article
Two-Dimensional Transition Metal Dichalcogenide: Synthesis, Characterization, and Application in Candlelight OLED
by Dipanshu Sharma, Sanna Gull, Anbalagan Ramakrishnan, Sushanta Lenka, Anil Kumar, Krishan Kumar, Pin-Kuan Lin, Ching-Wu Wang, Sinn-Wen Chen, Saulius Grigalevicius and Jwo-Huei Jou
Molecules 2025, 30(1), 27; https://doi.org/10.3390/molecules30010027 - 25 Dec 2024
Cited by 1 | Viewed by 1377
Abstract
Low-color-temperature candlelight organic light-emitting diodes (OLEDs) offer a healthier lighting alternative by minimizing blue light exposure, which is known to disrupt circadian rhythms, suppress melatonin, and potentially harm the retina with prolonged use. In this study, we explore the integration of transition metal [...] Read more.
Low-color-temperature candlelight organic light-emitting diodes (OLEDs) offer a healthier lighting alternative by minimizing blue light exposure, which is known to disrupt circadian rhythms, suppress melatonin, and potentially harm the retina with prolonged use. In this study, we explore the integration of transition metal dichalcogenides (TMDs), specifically molybdenum disulfide (MoS2) and tungsten disulfide (WS2), into the hole injection layers (HILs) of OLEDs to enhance their performance. The TMDs, which are known for their superior carrier mobility, optical properties, and 2D layered structure, were doped at levels of 0%, 5%, 10%, and 15% in PEDOT:PSS-based HILs. Our findings reveal that OLEDs doped with 10% MoS2 exhibit notable enhancements in power efficacy (PE), current efficacy (CE), and external quantum efficiency (EQE) of approximately 39%, 21%, and 40%, respectively. In comparison, OLEDs incorporating 10% of WS2 achieve a PE of 28%, a CE of 20%, and an EQE of 35%. The enhanced performance of the MoS2-doped devices is attributed to their superior hole injection and balanced carrier transport properties, resulting in more efficient operation. These results highlight the potential of incorporating 2D TMDs, especially MoS2, into OLED technology as a promising strategy to enhance energy efficiency. This approach aligns with environmental, social, and governance (ESG) goals by emphasizing reduced environmental impact and promoting ethical practices in technology development. The improved performance metrics of these TMD-doped OLEDs suggest a viable path towards creating more energy-efficient and health-conscious lighting solutions. Full article
Show Figures

Figure 1

9 pages, 2086 KiB  
Article
White Light-Emitting Flexible Displays with Quantum-Dot Film and Greenish-Blue Organic Light-Emitting Diodes
by Young Woo Kim, Seojin Kim, Chaeyeong Lee, Joo Hyun Jeong, Yun Hyeok Jeong, Yuhwa Bak, Seo Hyeon Kim, Sung Jin Park, Ko Eun Ham, Doeun Lee, Junpyo Song, Youngjin Song, Seung-Chan Jung, Oh Kwan Kwon, Jae-Hee Han, Sang Jik Kwon, Eou-Sik Cho and Yongmin Jeon
Micromachines 2024, 15(12), 1518; https://doi.org/10.3390/mi15121518 - 20 Dec 2024
Cited by 1 | Viewed by 1391
Abstract
White organic light-emitting diodes (OLEDs) represent a significant technology in the display industry for the achievement of full color. However, sophisticated technologies are required for white light emission. In this paper, we developed a simple white light-emitting display device using a quantum-dot (QD) [...] Read more.
White organic light-emitting diodes (OLEDs) represent a significant technology in the display industry for the achievement of full color. However, sophisticated technologies are required for white light emission. In this paper, we developed a simple white light-emitting display device using a quantum-dot (QD) film and a greenish-blue OLED. The resulting QD-OLED produced a high-purity white color with a color temperature of 6000 K (CIEx,y = 0.32, 0.34) and achieved a maximum brightness of 14,638 cd/m2 at 7 V. This paper reports the fabrication of a white light-emitting QD-OLED with a straightforward structure and technology suitable for flexible displays. Full article
(This article belongs to the Special Issue Organic Electronic-Based Devices for Biomedical Applications)
Show Figures

Figure 1

14 pages, 4331 KiB  
Article
Efficient and Stable Deep-Blue 0D Copper-Based Halide TEA2Cu2I4 with Near-Unity Photoluminescence Quantum Yield for Light-Emitting Diodes
by Fang Yuan, Xiaoyun Liu, Songting Zhang, Peichao Zhu, Fawad Ali, Chenjing Zhao, Shuaiqi He, Qianhao Ma, Jingrui Li, Kunping Guo, Lu Li and Zhaoxin Wu
Nanomaterials 2024, 14(23), 1919; https://doi.org/10.3390/nano14231919 - 28 Nov 2024
Viewed by 1085
Abstract
Achieving deep-blue light with high color saturation remains a critical challenge in the development of white light-emitting diode (LED) technology, necessitating luminescent materials that excel in efficiency, low toxicity, and stability. Here, we report the synthesis of [N(C2H5)4 [...] Read more.
Achieving deep-blue light with high color saturation remains a critical challenge in the development of white light-emitting diode (LED) technology, necessitating luminescent materials that excel in efficiency, low toxicity, and stability. Here, we report the synthesis of [N(C2H5)4]2Cu2I4 (TEA2Cu2I4) single crystals (SCs), which exhibit deep-blue photoluminescence (PL) at 450 nm. These crystals are characterized by a significant Stokes shift of 180 nm, a long lifetime of 1.7 μs, and an impressive photoluminescence quantum yield (PLQY) of 96.7% for SCs and 87.2% for polycrystalline films. The zero-dimensional structure is attributed to the proper spacing of triangular inorganic units [Cu2I4]2− by organic cations [N(C2H5)4]+. This structural arrangement facilitates broadband deep-blue light emission with phosphorescent characteristics, as evidenced by temperature-dependent PL and time-resolved photoluminescence (TRPL) measurements. The band gap properties of TEA2Cu2I4 were further elucidated through density functional theory (DFT) computations. Notably, the material exhibited minimal PL intensity degradation after continuous UV irradiation and one month of exposure to ambient conditions. Moreover, the polycrystalline film of TEA2Cu2I4 maintained substantial deep-blue emission even after one year of storage. Utilizing TEA2Cu2I4 thin film, we fabricated an electroluminescent device emitting deep-blue light with high color saturation, featuring CIE coordinates (0.143, 0.076) and a brightness of 90 cd/m2. The exceptional photophysical properties of TEA2Cu2I4 render it a highly promising candidate for optoelectronic applications. Full article
(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)
Show Figures

Figure 1

14 pages, 3618 KiB  
Article
Original Blue Light-Emitting Diphenyl Sulfone Derivatives as Potential TADF Emitters for OLEDs
by Margarita Anna Zommere, Natalija Tetervenoka, Anna Pidluzhna, Raitis Grzibovskis, Dovydas Blazevicius, Gintare Krucaite, Daiva Tavgeniene, Saulius Grigalevicius and Aivars Vembris
Coatings 2024, 14(10), 1294; https://doi.org/10.3390/coatings14101294 - 11 Oct 2024
Cited by 1 | Viewed by 1660
Abstract
Organic light-emitting diodes (OLEDs) have emerged as one of the dominant technologies in displays due to their high emission efficiency and low power consumption. However, the development of blue color emitters has fallen behind that of red and green emitters, posing challenges in [...] Read more.
Organic light-emitting diodes (OLEDs) have emerged as one of the dominant technologies in displays due to their high emission efficiency and low power consumption. However, the development of blue color emitters has fallen behind that of red and green emitters, posing challenges in achieving optimal efficiency, stability, and accessibility. In this context, thermally activated delayed fluorescence (TADF) emitters hold promise as a potential solution for cost-effective, exceptionally efficient, and stable blue OLEDs due to their potential high efficiency and stability. TADF is a principle where certain organic materials can efficiently convert both singlet and triplet excitons, theoretically achieving up to 100% internal quantum efficiency. This research focused on diphenyl sulfone derivatives with carbazole groups as TADF compounds. Quantum chemical calculations and photoluminescence properties show the potential TADF properties of the molecules. New materials exhibit glass transition temperatures that would classify them as molecular glasses. Depending on the structure of the molecule, the photoluminescence emission is in the blue or green spectral region. Organic light-emitting diodes were fabricated from neat thin films of emitters by the wet casting method. The best performance in the deep blue emission region was achieved by a device with a turn-on voltage of 4 V and a maximum brightness of 178 cd/m2. In the blue-green emission region, the best performance was observed by an OLED with a turn-on voltage of 3.5 V, reaching a maximum brightness of 660 cd/m2. Full article
(This article belongs to the Section Thin Films)
Show Figures

Figure 1

19 pages, 7160 KiB  
Article
Optical, Photophysical, and Electroemission Characterization of Blue Emissive Polymers as Active Layer for OLEDs
by Despoina Tselekidou, Kyparisis Papadopoulos, Konstantinos C. Andrikopoulos, Aikaterini K. Andreopoulou, Joannis K. Kallitsis, Stergios Logothetidis, Argiris Laskarakis and Maria Gioti
Nanomaterials 2024, 14(20), 1623; https://doi.org/10.3390/nano14201623 - 10 Oct 2024
Cited by 3 | Viewed by 1473
Abstract
Polymers containing π-conjugated segments are a diverse group of large molecules with semiconducting and emissive properties, with strong potential for use as active layers in Organic Light-Emitting Diodes (OLEDs). Stable blue-emitting materials, which are utilized as emissive layers in solution-processed OLED devices, are [...] Read more.
Polymers containing π-conjugated segments are a diverse group of large molecules with semiconducting and emissive properties, with strong potential for use as active layers in Organic Light-Emitting Diodes (OLEDs). Stable blue-emitting materials, which are utilized as emissive layers in solution-processed OLED devices, are essential for their commercialization. Achieving balanced charge injection is challenging due to the wide bandgap between the HOMO and LUMO energy levels. This study examines the optical and photophysical characteristics of blue-emitting polymers to contribute to the understanding of the fundamental mechanisms of color purity and its stability during the operation of OLED devices. The investigated materials are a novel synthesized lab scale polymer, namely poly[(2,7-di(p-acetoxystyryl)-9-(2-ethylhexyl)-9H-carbazole-4,4′-diphenylsulfone)-co-poly(2,6-diphenylpyrydine-4,4′-diphenylsulfone] (CzCop), as well as three commercially supplied materials, namely Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), poly[9,9-bis(2′-ethylhexyl) fluorene-2,7-diyl] (PBEHF), and poly (9,9-n-dihexyl-2,7-fluorene-alt-9-phenyl-3,6-carbazole) (F6PC). The materials were compared to evaluate their properties using Spectroscopic Ellipsometry, Photoluminescence, and Atomic Force Microscopy (AFM). Additionally, the electrical characteristics of the OLED devices were investigated, as well as the stability of the electroluminescence emission spectrum during the device’s operation. Finally, the determined optical properties, combined with their photo- and electro-emission characteristics, provided significant insights into the color stability and selectivity of each material. Full article
(This article belongs to the Special Issue Photofunctional Nanomaterials and Nanostructures)
Show Figures

Figure 1

27 pages, 8019 KiB  
Review
Advances in High-Efficiency Blue OLED Materials
by Xiaoxue Yang, Ge Mu, Kangkang Weng and Xin Tang
Photonics 2024, 11(9), 864; https://doi.org/10.3390/photonics11090864 - 13 Sep 2024
Cited by 9 | Viewed by 7653
Abstract
Organic light-emitting diode (OLED) technology has rapidly emerged in the display and lighting sectors due to its high contrast ratio, wide viewing angle, and sleek design. Beyond these attributes, OLEDs have also demonstrated crucial applications in medicine, fashion, sports, and more, leveraging their [...] Read more.
Organic light-emitting diode (OLED) technology has rapidly emerged in the display and lighting sectors due to its high contrast ratio, wide viewing angle, and sleek design. Beyond these attributes, OLEDs have also demonstrated crucial applications in medicine, fashion, sports, and more, leveraging their emissive properties and flexible design. As the cornerstone of full-color displays, blue OLEDs, whose performance directly impacts color rendition and saturation, have garnered significant attention from both scientific researchers and industrial practitioners. Despite the numerous advantages of OLED technology, blue OLEDs still confront formidable challenges in terms of luminous efficiency, durability, and material stability. This review examines the evolution of blue OLED materials over recent years, specifically focusing on three generations: fluorescent, phosphorescent, and thermally activated delayed fluorescence (TADF). Through molecular design, device structure optimization, and the application of innovative technologies, remarkable advancements have been achieved in enhancing the luminous efficiency, lifetime, and color purity of blue OLEDs. However, to advance commercialization, future efforts must not only ensure high efficiency and long lifetime but also improve material stability, environmental sustainability, and reduce development costs. Emerging materials such as thermally activated exciton materials and the application of hyperfluorescent (HF) OLED technology represent vital driving forces for the continuous advancement of blue OLED technology. It is anticipated that significant milestones will continue to be achieved in the development of highly efficient blue OLEDs in the future. Full article
(This article belongs to the Special Issue Organic Photodetectors, Displays, and Upconverters)
Show Figures

Figure 1

14 pages, 4065 KiB  
Article
The Improvement of Luminous Uniformity of Large-Area Organic Light-Emitting Diodes by Using Auxiliary Electrodes
by Fuh-Shyang Juang, Jia-You Chen, Wen-Kai Kuo and Krishn Das Patel
Photonics 2024, 11(9), 829; https://doi.org/10.3390/photonics11090829 - 2 Sep 2024
Viewed by 1397
Abstract
The study developed a large emission area of flexible blue organic light-emitting diodes (BOLED) on a polyethylene terephthalate/ Indium tin oxide (PET/ITO) substrate using a polycyclic skeleton ν-DABNA Thermally Activated Delayed Fluorescence (TADF) material. Initially, a 1 × 1 cm2 blue OLED [...] Read more.
The study developed a large emission area of flexible blue organic light-emitting diodes (BOLED) on a polyethylene terephthalate/ Indium tin oxide (PET/ITO) substrate using a polycyclic skeleton ν-DABNA Thermally Activated Delayed Fluorescence (TADF) material. Initially, a 1 × 1 cm2 blue OLED was fabricated to optimize the layer thickness. The blue OLED structure consisted of PET/ITO/HATCN/TAPC/UBH-21:ν-DABNA/TPBi/LiF/Al. However, as the emission area increased to 3.5 × 3.5 cm2, the current density decreased due to the resistance of PET/ITO, leading to luminance non-uniformity. To address this issue, auxiliary Au lines were added to the ITO anode to enhance current injection. Despite this, when the Au lines reached a thickness of 30 nm, average light emission was disrupted. To improve the luminescence characteristics of large-area PET/ITO OLEDs, a capping and planarization layer of PEDOT:PSS was applied. Grid uniformity revealed a significant increase in overall luminance uniformity from 74.1% to 87.4% with the addition of auxiliary Au lines. Further increases in grid line density slightly reduced uniformity but enhanced brightness, resulting in brighter, flexible, large-area blue OLED lighting panels. Full article
Show Figures

Figure 1

15 pages, 5361 KiB  
Article
Enhancing Blue Polymer Light-Emitting Diode Performance by Optimizing the Layer Thickness and the Insertion of a Hole-Transporting Layer
by A. Saad, N. Hamad, Rasul Al Foysal Redoy, Suling Zhao and S. Wageh
Polymers 2024, 16(16), 2347; https://doi.org/10.3390/polym16162347 - 20 Aug 2024
Cited by 2 | Viewed by 1380
Abstract
Polymer light-emitting diodes (PLEDs) hold immense promise for energy-efficient lighting and full-color display technologies. In particular, blue PLEDs play a pivotal role in achieving color balance and reducing energy consumption. The optimization of layer thickness in these devices is critical for enhancing their [...] Read more.
Polymer light-emitting diodes (PLEDs) hold immense promise for energy-efficient lighting and full-color display technologies. In particular, blue PLEDs play a pivotal role in achieving color balance and reducing energy consumption. The optimization of layer thickness in these devices is critical for enhancing their efficiency. PLED layer thickness control impacts exciton recombination probability, charge transport efficiency, and optical resonance, influencing light emission properties. However, experimental variations in layer thickness are complex and costly. This study employed simulations to explore the impact of layer thickness variations on the optical and electrical properties of blue light-emitting diodes. Comparing the simulation results with experimental data achieves valuable insights for optimizing the device’s performance. Our findings revealed that controlling the insertion of a layer that works as a hole-transporting and electron-blocking layer (EBL) could greatly enhance the performance of PLEDs. In addition, changing the active layer thickness could optimize device performance. The obtained results in this work contribute to the development of advanced PLED technology and organic light-emitting diodes (OLEDs). Full article
(This article belongs to the Special Issue Polymers/Their Hybrid Materials for Optoelectronic Applications)
Show Figures

Figure 1

Back to TopTop