Review
Chemistry, Multidisciplinary
Yaxiong Wang, Ju Hui Yun, Lei Wang, Jun Yeob Lee
Summary: Improving the performance of blue OLEDs is a challenge in both scientific and industrial communities, with optimizing the fabrication process of devices, developing stable and efficient luminescence and transporting materials, and developing host materials with high triplet energy being key approaches. The bottleneck lies in improving operational lifetimes, decreasing efficiency roll-off, and maintaining high quantum efficiency, and more innovation is needed in this field.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Xiangchen Hong, Dongdong Zhang, Chen Yin, Qi Wang, Yuewei Zhang, Tianyu Huang, Jinbei Wei, Xuan Zeng, Guoyun Meng, Xiang Wang, Guomeng Li, Dezhi Yang, Dongge Ma, Lian Duan
Summary: This study presents a new molecular design strategy to enhance the performance of carbazole-benzonitrile derivatives (CzBNs) by extending the acceptor pi-system with parapositioned pi-conjugation tails. The results show that this molecular structure not only enhances the TADF properties of the materials but also improves the outcoupling efficiency of light. The blue and white fluorescent devices designed based on this strategy both achieve impressive performances.
Article
Chemistry, Organic
Mizhen Sun, Chenglin Ma, Mingliang Xie, Lizhi Chu, Xin Wang, Qikun Sun, Wenjun Yang, Shanfeng Xue
Summary: In this study, two donor-acceptor (D-A) type blue emitters with bipolar transmission were synthesized, and their hybridized local and charge-transfer (HLCT) excited state was demonstrated to achieve high electron mobility. The single crystal results showed that tPPIDPO exhibited effective acceptor-acceptor π-stacking and highly ordered molecular arrangement, leading to higher electron and more balanced carrier mobilities. The non-doped blue OLED based on tPPIDPO achieved a maximum external quantum efficiency (EQEmax) of approximately 7.0%, which is among the highest reported for D-A type blue fluorescence emitters with HLCT using DPO as the acceptor. The development of a blue emitter with effective acceptor-acceptor π-stacking improves and balances carrier mobilities, resulting in higher device efficiency.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Mizhen Sun, Chenglin Ma, Mingliang Xie, Lizhi Chu, Xin Wang, Qikun Sun, Wenjun Yang, Shanfeng Xue
Summary: This study synthesized two donor-acceptor (D-A) type blue emitters and improved electron mobility by introducing the acceptor molecule DPO. The molecules exhibited high electron mobility and balanced carrier mobility, leading to a highly efficient blue OLED device.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Applied
Vilas Venunath Patil, Junseop Lim, Jun Yeob Lee
Summary: In this study, we propose an asymmetric anthracene-based molecule ATDBT for high efficiency doped and non-doped organic light-emitting diodes (OLEDs). The ATDBT accelerates the triplet to singlet up-conversion process through triplet-triplet annihilation and structurally induced bipolar characteristics. The fabricated devices achieve high efficiency with a small efficiency roll-off at high luminance.
Article
Chemistry, Multidisciplinary
Ji-Kun Li, Ming-Yu Zhang, Le Zeng, Ling Huang, Xiao-Ye Wang
Summary: In this study, the first NIR-absorbing B,N-heteroarene-based sensitizer (BNS) with multi-resonance thermally activated delayed fluorescence (MR-TADF) is developed to achieve efficient NIR-to-blue TTA-UC. The small energy gap between the singlet and triplet excited states (0.14 eV) of BNS suppresses the energy loss during ISC, and its long-delayed fluorescence lifetime (115 μs) contributes to efficient triplet energy transfer. As a result, the largest anti-Stokes shift (1.03 eV) among all heavy-atom-free NIR-activatable TTA-UC systems is obtained with a high TTA-UC quantum yield of 2.9% (upper limit 50%).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
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
Chemistry, Applied
Seokhoon Jang, Kyung Hyung Lee, Soojin Hong, Jun Yeob Lee, Youngu Lee
Summary: Novel n-type host materials based on tricyclic aromatic compounds, dibenzo [b,d] furan and dibenzo[b,d]thiophene, were successfully synthesized and characterized for high-performance blue thermally activated delayed fluorescence organic light-emitting devices (OLEDs). The introduction of nitrile and diphenyltriazine functional groups at specific positions resulted in materials with excellent thermal stability, high triplet energy, and low-lying LUMO energy levels. These materials showed superior performance in terms of efficiency, driving voltage, and device lifetime compared to OLEDs with a single p-type host material.
Article
Materials Science, Multidisciplinary
Junhua Xie, Jingwen Yao, Yanfeng Dai, Qian Sun, Dezhi Yang, Xianfeng Qiao, Dongge Ma
Summary: In this paper, high-efficiency blue organic light-emitting diodes (OLEDs) were fabricated by introducing a thin DMAC-DPS layer adjacent to the emitter. The resulting blue OLEDs showed improved turn-on voltage, efficiency, and efficiency roll-off. Further inserting phosphorescent materials in ultra-thin layers in a blue emitter allowed the fabrication of a warm white OLED with high efficiency and a high color rendering index (CRI).
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Applied
Chongping Song, Jiaqi Li, Houyu Zhang
Summary: A class of bipolar host molecules with hole-transporting and electron-transporting groups connected to a TPSi core were designed and analyzed for blue phosphorescence. The calculated results showed that these designed molecules have potential as host materials for blue phosphorescence. The position of the N atom in pyridine and carboline plays a significant role in the molecular properties. This study provides insights into the structure-property relationship of TPSi-based host molecules and offers guidance for efficient bipolar host materials for blue phosphorescence.
Article
Chemistry, Multidisciplinary
Cui Wang, Christina Wegeberg, Oliver S. Wenger
Summary: We report the first example of sensitized triplet-triplet annihilation upconversion (sTTA-UC) based on a 3d(6) metal photosensitizer, which shows comparable performance to precious metal-based analogues. The study provides a proof-of-concept for the application of first-row analogues in photochemical reactions triggered by excitation wavelengths close to near-infrared.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Rajendra Kumar Konidena, Junseop Lim, Jun Yeob Lee
Summary: A new molecular design based on carbazole was developed for the development of high triplet energy bipolar host materials for blue PhOLEDs. Two new isomeric host materials were synthesized, showing high triplet energy without compromising bipolar charge transporting property. The compounds demonstrated good performance in blue PhOLEDs applications, with higher EQE, current efficiency, and efficiency roll off compared to their analogues.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2022)
Article
Chemistry, Physical
Zachary A. VanOrman, Carl R. Conti, Geoffrey F. Strouse, Lea Nienhaus
Summary: The study fills a gap in the field of photon upconversion by introducing CdTe nanorods as a new class of triplet sensitizers for red-to-blue photon upconversion, achieving high efficiency and low threshold power.
CHEMISTRY OF MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Thanh B. Nguyen, Hajime Nakanotani, Chin-Yiu Chan, Shunta Kakumachi, Chihaya Adachi
Summary: A proof of concept was presented for maximizing the TTU contribution yield in blue OLEDs through the doping of TADF molecules. The bipolar carrier transport ability of TADF materials enables direct carrier recombination on the molecules, expanding the recombination zone. Although the external electroluminescence quantum efficiency of OLEDs is slightly lower, the TTU efficiency approaches the upper limit. Furthermore, by employing TADF molecules, the operational device lifetime of OLEDs increased by five times, highlighting the importance of expanding the recombination zone for enhancing overall OLED performance in TTU-OLEDs.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Tsubasa Kashino, Masanori Hosoyamada, Rena Haruki, Naoyuki Harada, Nobuhiro Yanai, Nobuo Kimizuka
Summary: The study presents the first example of achieving efficient and air-stable photon upconversion in rigid epoxy resins by homogeneously dispersing emitter molecules without aggregation in the resin. This innovative approach opens up new possibilities for real-world applications.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Wook Song, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
Article
Materials Science, Multidisciplinary
Jeong Min Choi, Ji Han Kim, Yu Jin Kang, Jun Yeob Lee
ORGANIC ELECTRONICS
(2017)
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
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
Ji Han Kim, Minsik Eum, Tae Hyung Kim, Jun Yeob Lee
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
Materials Science, Multidisciplinary
Jinfei Dai, Chenjing Zhao, Jie Xu, Hossein Roshan, Hua Dong, Francesco Di Stasio, Fang Yuan, Bo Jiao, Zhaoxin Wu
Summary: In this study, the performance of perovskite nanocrystal light emitting diodes (PNC-LEDs) was enhanced through rational device structure design and the application of high-performance perovskite nanocrystal emitting layers.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Jia-Hua Yeh, Suhendro Purbo Prakoso, Leon Lukhas Santoso, Shi-Ju Chen, Bryan Chiang, Ju-Chieh Cheng, Ru-Ning Zhang, Yu-Cheng Chiu
Summary: This study demonstrates the application of a renewable material called dextrin-SMS in the production of electret filters and transistor memory. Dextrin-SMS material can maintain prolonged electrostatic charges and has a relatively wide memory window, making it suitable for the production of biodegradable face masks and green electronics.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Ahmad Telfah, Qais M. Al-Bataineh, Ahmad A. Ahmad, Rund Abu-Zurayk, Carlos J. Tavares, Johannes Etzkorn, Farzad Foadian
Summary: Polyacrylic acid complexed with polyaniline (PAA/PANI) composite materials have the potential to form organic mixed ion-electron conductive (OMIEC) films, which can be used in optoelectronic and energy storage applications. The composite films are formed through an acid-base reaction, resulting in strong electrostatic interactions and intermolecular hydrogen bonds between PANI and PAA. The separation of PANI-rich domains from PAA-rich matrix in the composite films is observed. The electrical conductivity of the composite films is higher when the content of PANI is 33 wt%, due to the high ionic-electronic coupling at the interface between phase-separated regions.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Min-Chih Hou, Dian Luo, Yu-Ting Huang, Shun-Wei Liu, Chin-Wei Lu, Chih-Hao Chang, Hai-Ching Su
Summary: Light-emitting electrochemical cells (LECs) have great potential for novel emission applications, but their relatively low device efficiency hinders their competitiveness with other emission technologies. A study finds that increasing the concentration of small TiO2 nano-particles in the diffuser film can enhance light extraction and improve the device efficiency of LECs.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Qiaoli Niu, Yao Xu, Jun Yang, Wei Hua, Baoxiang Chai, Zequan Zhang, Yuhui Ma, Wenjin Zeng, Ana Flavia Nogueira, Ruidong Xia
Summary: By introducing CPB as a defect passivation agent in the perovskite precursor solution, the optoelectronic properties of perovskite films can be significantly improved and non-radiative carrier recombination can be effectively suppressed. CPB-modified perovskite solar cells exhibit lower trap-state density and stronger carrier migration capability, leading to enhanced power conversion efficiency and stability.
ORGANIC ELECTRONICS
(2024)
Article
Materials Science, Multidisciplinary
Hulya Ozturk Dogan, Fatma Yildirim, Zeynep Orhan, Ali Ben Ahmed, Mostefa Benhaliliba, Sakir Aydogan
Summary: In this study, efficient self-powered visible and UV photodetectors based on hybrid organic-inorganic materials were demonstrated. The photodetectors showed excellent UV detecting capability and good photoresponsivity.
ORGANIC ELECTRONICS
(2024)
