Article
Chemistry, Multidisciplinary
Jia-Jia Wei, Yong-Jian Yang, Xiang-Yang Liu, Runlai Li, Shu-an Li
Summary: Explored a simple and efficient strategy to derivatize the fluorene unit and achieved high-efficiency green PHOLEDs.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Kwangmo Yang, Sungho Nam, Joonghyuk Kim, Eun Suk Kwon, Yongsik Jung, Hyeonho Choi, Ji Whan Kim, Jaesang Lee
Summary: Despite decades of research, the cause of short lifetimes in blue PHOLEDs remains elusive. This study investigates how the electrical properties of the EML in blue PHOLEDs affect device degradation, finding that a high density of dopant carriers is the major factor triggering TPA-induced defects. To achieve long device lifetimes, minimizing dopant carrier density and controlling the non-uniform distribution of defects are crucial. These factors can be predetermined and controlled by the charge mobilities of the PHOLED EML, allowing for the realization of long-lifetime blue PHOLEDs.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Junsu Ha, Junseop Lim, Jun Yeob Lee
Summary: The use of a mCBP:CzBFPmSi mixed host in PhOLEDs results in high external quantum efficiency over 20% and low efficiency roll-off.
SCIENCE CHINA-MATERIALS
(2022)
Article
Chemistry, Applied
Hyung Jin Cheon, Chul Woong Joo, Da Yeon Lee, Gunel Huseynova, Jae-Hyun Lee, Jonghee Lee, Yun-Hi Kim
Summary: A new iridium complex based on (4-(3,5-dimethylphenyl)-2-(m-tolyl)pyridine) was synthesized for highly efficient orange phosphorescent organic light-emitting diodes (PhOLEDs). The introduction of a methyl substituent into the 4-position of the phenyl ring in a phenylpyridine chelating ligand was found to significantly improve the performance of PhOLEDs. The newly-synthesized iridium complex exhibited maximum external quantum and current efficiencies of 20.33% and 61.16 cd/A, respectively, with these values maintained even at high luminance levels.
Article
Chemistry, Multidisciplinary
Sumeyye Yalduz, Mehmet Yilmaz
Summary: In this study, furo[2,3-d]pyrido[1,2-a]pyrimidin-4-ones were synthesized by microwave-assisted radical cyclizations. The reaction was performed between 2-hydroxy-4H-pirido[1,2-a]pirimidin-4-ones and conjugated alkenes and phenylacetylene using Mn(OAc)(3) as a catalyst. Different reaction conditions were compared to optimize the reaction. The obtained compounds were characterized using spectroscopic techniques and XRD analysis.
Article
Chemistry, Applied
Yuhuan Chen, Weian Chen, Yanqiong Zheng, Qingyu Zhang, Bingjia Zhao, Longlong Chen, Jinhai Huang
Summary: In this work, two novel bipolar host materials, a-CzDp and b-CzDp, were designed and synthesized. These materials exhibited good thermal stability and deep energy levels. When used as hosts in PhOLED devices, they showed excellent luminance and quantum efficiency. The results demonstrate the potential of a-CzDp and b-CzDp as efficient host materials for red PhOLEDs.
Article
Chemistry, Applied
Jihoon Kang, Ha Lim Lee, Junseop Lim, Jun Yeob Lee
Summary: In organic light-emitting diodes (OLEDs), host engineering is crucial for improving device performance. However, achieving high efficiency in blue phosphorescent OLEDs remains challenging due to the high triplet energy of blue phosphors. In this study, a thermally activated delayed fluorescence-type host with a sterically modulated carbazole-triazine backbone structure is developed. By incorporating a spatially twisted pi-spacer, the host exhibits a short delayed decay time and high triplet energy with a small singlet-triplet energy splitting. This photophysical modulation enables efficient utilization of triplet excitons, leading to significantly improved device performance with a maximum external quantum efficiency of 23.6%.
Article
Materials Science, Multidisciplinary
Jae-Min Kim, Kyung Hyung Lee, Jun Yeob Lee
Summary: This study comprehensively investigates the exciton dynamics of electroplex hosts in blue PhOLEDs and correlates the steady-state triplet excitons in the host with device lifetime. A degradation modeling considering the impact of host triplet excitons and dopants on material degradation was developed, leading to enhanced operational stability. The characterization method and numerical modeling can help predict the device lifetime of PhOLEDs for specific host materials.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Optics
Linyu Cao, Kody Klimes, Yunlong Ji, Tyler Fleetham, Jian Li
Summary: The newly developed tetradentate Pd(ii) complex Pd3O8-P with near unity photoluminescent quantum yield has potential applications in high-brightness, long-lifetime OLED devices. Its features include high quantum efficiency, reduced efficiency roll-off, and an estimated operational half-lifetime of several million hours.
Review
Chemistry, Inorganic & Nuclear
Jayaraman Jayabharathi, Venugopal Thanikachalam, Shanmugam Thilagavathy
Summary: This review presents a low-cost fabrication process for efficient phosphorescent organic light-emitting diodes (PhOLEDs) based on Ir(III) complexes. The excellent charge transportation and injection abilities of Ir (III) complexes contribute to their usage as both charge transport materials and emissive materials in PhOLEDs. The reduced intermolecular aggregation and excellent hole and electron transporting abilities of Ir(III) complexes lead to highly efficient PhOLEDs. In doped PhOLEDs, the efficiency is determined by exciton confinement, charge trapping, and dopant concentration.
COORDINATION CHEMISTRY REVIEWS
(2023)
Article
Materials Science, Multidisciplinary
Wentong Gao, Shihai Cao, Bing Han, Nengquan Li
Summary: This paper presents the design and preparation of a simple solution-processable host material TPA-PyF2 for efficient solution-processed PhOLEDs. The TPA-PyF2 features a sigma-linkage between donor and acceptor units, providing high triplet energy level and film morphological stability. The experimental results demonstrate that TPA-PyF2 achieves high current efficiency, power efficiency, and luminance in blue solution-processed OLEDs.
Review
Multidisciplinary Sciences
Yanqin Miao, Mengna Yin
Summary: UEMLs have been widely applied to fabricate OLEDs and have advantages of simplified device structure and preparation process, more flexible design, lower material consumption, and complete exciton utilization.
Article
Materials Science, Multidisciplinary
Liang Zhao, Xiaozhe Cheng, Weizhen Xia, Lingling Yao, Zhitao Dou, Haibin Xue, Hong Lian, Yongquan Qu, Qingchen Dong
Summary: In this study, two bipolar host materials, DBTPC1 and DBTPC2, were designed and synthesized using different linkages between carbazole, pyridine, and dibenzothiophene. The photophysical and thermal properties of these hosts were systematically investigated. The rigid molecular structures of these hosts contribute to high glass transition temperatures, ensuring excellent thermal stability. When used as hosts in red phosphorescent organic light-emitting devices (PHOLEDs) with Ir(piq)2acac as an emitter, DBTPC1 and DBTPC2 display maximum external quantum efficiencies (EQEs) of 18.8% and 13.2%, respectively. Experimental results demonstrate that DBTPC1 outperforms the commercial host CBP, making it a promising candidate for practical applications in red PHOLEDs and future exploration in multi-color PHOLEDs.
Article
Nanoscience & Nanotechnology
Hakjun Lee, Yeonju Jeong, Taekyung Kim
Summary: The degradation mechanism of blue-fluorescent OLEDs has been studied to improve their limited operational lifetime. Previous studies focused on the time to reach 50% initial luminance (LT50) as a critical factor. However, due to human eye sensitivity, only 3-5% luminance changes can be recognized. This study proposes a new methodology to analyze early-stage degradation factors, such as LT97, in blue-fluorescent OLEDs.
Article
Chemistry, Applied
Ju Hui Yun, Junseop Lim, Won Jae Chung, Jun Yeob Lee
Summary: A novel n-type host material with exciton stabilizing function was developed for blue PhOLEDs, demonstrating high efficiency and long lifetime. The incorporation of carbazole unit significantly improved device lifetime, serving as a key factor in exciton stabilization.
Article
Materials Science, Multidisciplinary
Jeong Min Choi, Woochul Lee, Kong Kyeom Kim, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
Article
Materials Science, Multidisciplinary
Wook Song, Taekyung Kim, Yoonkyoo Lee, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
Article
Materials Science, Multidisciplinary
Hyeong Min Kim, Jeong Min Choi, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
Article
Materials Science, Multidisciplinary
Wook Song, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
Article
Materials Science, Multidisciplinary
Chan Seok Oh, Chang-Ki Moon, Jeong Min Choi, Jin-Suk Huh, Jang-Joo Kim, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
Article
Materials Science, Multidisciplinary
Hyeong Min Kim, Jeong Min Choi, Jun Yeob Lee
Review
Materials Science, Multidisciplinary
Wook Song, Jun Yeob Lee
ADVANCED OPTICAL MATERIALS
(2017)
Article
Chemistry, Applied
Kiun Cheong, Seung Chan Kim, Jun Yeob Lee
Summary: This study explores the potential of using o-carborane as a new acceptor in designing donor-acceptor (D-A) type thermally activated delayed fluorescence (TADF) materials. The designed D-A type TADF emitter exhibits deep red emission as proven by delayed fluorescence and electroluminescence analysis. The maximum external quantum efficiency of the devices is found to be 5.2% in the doped device and 2.1% in the non-doped device.
Article
Chemistry, Applied
Ju Hui Yun, Jun Yeob Lee
Article
Chemistry, Applied
Jeong Min Choi, Dong Ryun Lee, Jun Yeob Lee
Article
Nanoscience & Nanotechnology
Sung Yong Byeon, Ji Han Kim, Jun Yeob Lee
ACS APPLIED MATERIALS & INTERFACES
(2017)
Article
Chemistry, Multidisciplinary
Yirang Im, Seong Yong Byun, Ji Han Kim, Dong Ryun Lee, Chan Seok Oh, Kyoung Soo Yook, Jun Yeob Lee
ADVANCED FUNCTIONAL MATERIALS
(2017)
Review
Chemistry, Physical
Yirang Im, Mounggon Kim, Yong Joo Cho, Jeong-A Seo, Kyoung Soo Yook, Jun Yeob Lee
CHEMISTRY OF MATERIALS
(2017)
Article
Chemistry, Multidisciplinary
Jin-Wook Lee, Yung Ji Choi, June-Mo Yang, Sujin Ham, Sang Kyu Jeon, Jun Yeob Lee, Young-Hyun Song, Eun Kyung Ji, Dae-Ho Yoon, Seongrok Seo, Hyunjung Shin, Gil Sang Han, Hyun Suk Jung, Dongho Kim, Nam-Gyu Park
Article
Chemistry, Applied
Yu Jin Kang, Jun Yeob Lee
Review
Chemistry, Multidisciplinary
Dan He, Yawen Li, Fuwen Zhao, Yuze Lin
Summary: High trap density in organic solar cells leads to localized charge carriers and reduced carrier lifetime, limiting device efficiency. This feature article summarizes the recent advances of trap suppression by material design and device engineering.
CHEMICAL COMMUNICATIONS
(2024)
Review
Chemistry, Multidisciplinary
Olivier Monfort, Arshitha Madhusudhan, Martin Motola
Summary: This article presents the advantages of coupling photocatalysis and Fenton-based processes for environmental remediation and discusses their synergy. It critically examines the simultaneous triggering of these two processes and provides insights into research approaches. The study aims to enhance understanding of this complex process and highlight the potential integration of new catalysts in current wastewater treatment technology.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Manideepa Dhar, Chittaranjan Mishra, Avijit Das, Uttam Manna
Summary: An approach of 'polymerization of monomers in its aggregated form' has been introduced to tailor the water wettability of fibrous and porous substrates, achieving hydrophobicity to superhydrophobicity transition, as well as patterned wettability. This facile chemical method provides a durable coating with adjustable and patterned wettability for various potential applications.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Saswat Ranjan Bhoi, Chhanda Debnath, Shikha Gandhi
Summary: In this article, a novel catalytic reaction using Pd(0) and Bronsted acid is reported for the synthesis of biologically important imidazolidinone-fused N-heterocycles through redox-neutral intramolecular N-allylation of indoles and pyrroles with alkynes. This atom-economical method is applicable to a wide range of substrates and eliminates the need for leaving groups or oxidizing agents commonly used in traditional allylation reactions.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Longkun Chen, Mingshuai Zhang, Meichen Liu, Zhuoyuan Liu, Yuetong Qiu, Zhilai Zhang, Fuchao Yu, Jiuzhong Huang
Summary: In this study, an efficient Rh(III)-catalyzed selective mono- and dual-C-H bond functionalization/cyclization with iodonium ylide as the sole coupling partner was demonstrated. Fused benzodiazepine skeletons were obtained in excellent yields, providing an improved approach to dual C-H unsymmetrical functionalization.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Alice Kennett, Sven Epple, Gabriella van der Valk, Irene Georgiou, Evelyne Gout, Romain R. Vives, Angela J. Russell
Summary: This study presents the design and synthesis of sulfated disaccharide inhibitors based on IdoA(2S)-GlcNS(6S), which showed potent inhibition of Sulf-2. The results suggest that IdoA(2S)-GlcNS(6S) is the shortest fragment size required for effective inhibition of Sulfs, and a trisulfated disaccharide is identified as the minimal fragment size of heparan sulfate for effective endosulfatase inhibition.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Mauro Garbini, Andrea Brunetti, Riccardo Pedrazzani, Magda Monari, Massimo Marcaccio, Giulio Bertuzzi, Marco Bandini
Summary: The self-adaptability of galvanostatic electrolysis was found to be helpful in a multistage chemo- and diastereoselective electrochemically promoted cyclodimerization of chalcones. Through a series of reductive events, densely functionalized cyclopentanes with five contiguous stereocenters were obtained (25 examples, yields up to 95%, dr values up to >20:1). Further experimental and electrochemical investigations indicated the crucial role of dynamic kinetic resolution of the aldol intermediate in the reaction mechanism.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Dhananjay S. Nipate, Neha Meena, Prakash N. Swami, Krishnan Rangan, Anil Kumar
Summary: In this study, the synthesis of functionalized benzo[a]phenazines and indazolo[2,3-a]quinolines was achieved through Rh(III)-catalyzed oxidative annulation of 2-arylquinoxalines and 2-aryl-2H-indazoles with allyl alcohols. The method showed a wide substrate scope, excellent functional group tolerance, good to high yields of annulated products, and the capability for scaled-up synthesis. A tentative mechanism of the annulation reaction was proposed based on a preliminary mechanistic investigation.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Ruonan Zhang, Abudukadi Tudi, Xia Yang, Xuping Wang, Zhihua Yang, Shujuan Han, Shilie Pan
Summary: A new lead tellurium borate material with a unique fundamental building block [B4O10] was synthesized and found to exhibit high birefringence. The structure-property relationship was discussed using first-principles calculations.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Amresh Kumar Singh, Baishali Thakurta, Anupam Giri, Monalisa Pal
Summary: This study introduces three key concepts for the quick synthesis of large-scale high-quality 2D materials films and their utilization in device fabrication.
CHEMICAL COMMUNICATIONS
(2024)
Article
Chemistry, Multidisciplinary
Reina Hagiwara, Shun Nishimura, Kosuke Okeyoshi
Summary: A copolymer-conjugated nanocatalytic system has been developed to improve electron transfer and enhance photoinduced H2 generation.
CHEMICAL COMMUNICATIONS
(2024)
