Article
Chemistry, Multidisciplinary
Jiangnan Xia, Xincan Qiu, Yu Liu, Ping-An Chen, Jing Guo, Huan Wei, Jiaqi Ding, Haihong Xie, Yawei Lv, Fuxiang Li, Wenwu Li, Lei Liao, Yuanyuan Hu
Summary: A general device fabrication strategy for metal halide perovskite (MHP) FETs is proposed, which successfully obtains transparent perovskite FETs. The strategy involves the use of ferroelectric copolymer poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) as the dielectric, which solves the challenging issue of gate-electric-field screening effect in MHP FETs. Additionally, ultra-thin SnO2 is inserted between the source/drain electrodes and MHPs to facilitate electron injection. These FETs have the attractiveness of low-cost, large-area transparent electronics applications.
Article
Chemistry, Physical
Masaya Nishinaka, Hiroaki Jinno, Yasutoshi Jimbo, Sunghoon Lee, Jiabin Wang, Wonryung Lee, Tomoyuki Yokota, Takao Someya
Summary: Organic electrochemical transistors (OECTs) are widely used for monitoring electrophysiological activities, with the transconductance of OECTs using PEDOT:PSS channel layer being proportional to the channel thickness, which is essential for forming a thick channel layer; spray coating technique can successfully form a thick and uniform PEDOT:PSS layer, resulting in a high-transconductance and ultraflexible OECT with a sufficiently rapid response.
Article
Nanoscience & Nanotechnology
Askold A. Trul, Victoria P. Chekusova, Daniil S. Anisimov, Oleg V. Borshchev, Marina S. Polinskaya, Elena V. Agina, Sergey A. Ponomarenko
Summary: This study investigates the electrical and sensing properties of ultrathin OFETs based on BTBT dimers with different aliphatic spacer lengths, fabricated by Langmuir-Blodgett, Langmuir-Schaefer, or spin-coating techniques. By optimizing the interface dielectric layer, uniform low-defect ultrathin semiconducting layers are obtained, resulting in improved electrical performance. The highest field-effect mobility of 0.47 cm(2) V-1 s(-1) is achieved for devices fabricated by LS method on top of a poly(methyl methacrylate) interface layer. The promising operational stability leads to advanced sensory properties, with a record limit of detection of 30 ppb for sensing ethanethiol in humid air.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Xue Wang, Pengfei Zhao, Yanhong Tong, Shanlei Guo, Guodong Zhao, Mingxin Zhang, Hongyan Yu, Xiaoli Zhao, Qingxin Tang, Yichun Liu
Summary: By inserting a PEDOT: PSS layer onto the rGO electrode, high-conductive transparent and flexible electrodes can be fabricated, which exhibit high precision, high transparency, and good adherence. The resulting organic transistor array shows enhanced modulation effect, increased electron mobility, and stable operation on human skin.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Materials Science, Multidisciplinary
Federico Chianese, Andrea Candini, Stefano Lumetti, Neeraj Mishra, Camilla Coletti, Marco Affronte, Antonio Cassinese
Summary: This work reports on fully functional sub-micrometric low voltage OFETs using graphene as the source-drain electrodes pair and a high-x ultra-thin dielectric in a local gate architecture. The influence of graphene electrodes on the miniaturization of organic devices, contact resistances, and parasitic overlap gate capacitance on device bandwidth has been assessed. Impedance spectroscopy of the electrodes revealed cut-off frequencies as high as 10^5 Hz, emphasizing the unique role of graphene quantum capacitance in such architectures.
Article
Chemistry, Physical
Tahereh Nematiaram, Alessandro Troisi
Summary: Transparent conducting materials are crucial for optoelectronic devices, but it is challenging to develop high-performance materials that are both transparent and conductive, especially for p-type-doped materials. In this study, a large set of molecular semiconductors from the Cambridge Structural Database were evaluated to identify potential transparent conducting materials based on p-type-doped molecular crystals. Candidate materials were selected based on high HOMO energy levels, high charge carrier mobility, and a high threshold for energy absorption. Additionally, the calculation of excited-state energy was found to be essential for accurately predicting material transparency. Through virtual screening, molecular semiconductors with desirable mobility and transparency can be discovered.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Hyeok-jin Kwon, Heqing Ye, Kyuwon Shim, Henok Getachew Girma, Xiaowu Tang, Bogyu Lim, Yejin Kim, Jihoon Lee, Chan Eon Park, Seo-Hyun Jung, Jong Mok Park, Yu Jin Jung, Do-Hoon Hwang, Hoyoul Kong, Se Hyun Kim
Summary: New solution-processable copolymers containing carboxyl and hydrophobic functionalities were synthesized, with the use of a fluorophenyl azide (FPA) based UV-assisted crosslinker to promote the movement of polar carboxyl groups and hydrophobic functionalities in thin film. This strategy maintained high dielectric constant characteristics and hydrophobic surface, eliminating trapsites and allowing stable operation and efficient charge transport.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Tommaso Losi, Lukasz Witczak, Mateusz Lysien, Pietro Rossi, Paola Moretti, Chiara Bertarelli, Virgilio Mattoli, Mario Caironi
Summary: Organic electronics is a promising technology for low-cost and simple device fabrication. This study successfully integrated direct written metal contacts in fully solution fabricated n-type OFETs, achieving a short channel of 1.4 μm and a high transition frequency of 25.5 MHz at 25 V. This demonstrates the potential of additive, high-resolution direct-writing techniques for high-frequency organic electronics.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Filipp Talalaev, Sergey Luchkin, Alexander V. Mumyatov, Ivan S. Zhidkov, Maxim V. Lobano, Nikita A. Emelianov, Sergey D. Babenko, Ernst Z. Kurmaev, Sergey M. Aldoshin, Pavel A. Troshin
Summary: Rare earth metal oxides (REOs) with high dielectric constants are proposed as promising gate dielectric materials for field-effect transistors. This paper presents a method for depositing uniform REO gate dielectric coatings by oxidizing thin rare earth metal films at relatively low temperatures. Extensive experiments on organic field-effect transistors (OFETs) demonstrate that OFETs with REO gate dielectrics exhibit considerably better characteristics compared to those with electrochemically grown aluminum oxide dielectric. The flexibility of OFETs on a plastic substrate makes this approach highly attractive for developing improved flexible and wearable electronic devices.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Shanlei Guo, Yanhong Tong, Xue Wang, Mingxin Zhang, Hongyan Yu, Hang Ren, Qingxin Tang, Guanghao Lu, Yichun Liu
Summary: Organic semiconductors are brittle and have limited stretchability, which hinders their applications in stretchable electronics. In this study, a stretchable semiconductor composite was developed by blending a brittle organic semiconductor with an elastomer, resulting in improved crack-onset strain, transparency, and mobility. The nonuniform distribution of the semiconductor fibers in the composite film weakens the effect of device configuration on mobility. This work presents a feasible path for using brittle organic semiconductors in transparent stretchable electronics.
ADVANCED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Tung Nguyen-Dang, Sangmin Chae, Kelsey Harrison, Luana C. Llanes, Ahra Yi, Hyo Jung Kim, Shantonu Biswas, Yon Visell, Guillermo C. Bazan, Thuc-Quyen Nguyen
Summary: A wet processing method for fabricating high-performance OECTs is reported, simplifying the fabrication process and enhancing the electrical properties of the active material. OECTs fabricated using this method have been demonstrated to be applicable for chemical sensors with good detection capabilities.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Review
Chemistry, Multidisciplinary
Lukasz Janasz, Michal Borkowski, Paul W. M. Blom, Tomasz Marszalek, Wojciech Pisula
Summary: Organic semiconductors face limitations in their practical applicability due to low environmental stability and poor charge carrier mobilities. Blending with thermoplastic polymers and elastomers can overcome these restrictions and induce new material properties, showcasing great potential for flexible and stretchable electronics. Improved device properties such as charge carrier mobility, life-time, sensing ability, and mechanical behavior are achieved through blending with insulators, offering promise for various electronic devices and semiconductor classes.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Juhui Oh, Ju-Hyeon Kim, Yong Ryun Kim, Ardalan Armin, Sanseong Lee, Kiyoung Park, Hongkyu Kang, Kwanghee Lee
Summary: We demonstrate a new tungsten oxide (WO3)-based multilayer as a highly conductive and transparent top electrode for transparent organic solar cells (T-OSCs). By optimizing the thicknesses of the multilayer electrodes using optical simulations, we achieve a T-OSC with a high power conversion efficiency (PCE) of 7.0% and a full device average photopic transmittance (APT) of 46.7%. Furthermore, the WO3-based T-OSCs exhibit superior thermal stability at 85 degrees C in an N2 atmosphere, maintaining 98% of the initial PCE after about 231 hours.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Juhui Oh, Ju-Hyeon Kim, Yong Ryun Kim, Ardalan Armin, Sanseong Lee, Kiyoung Park, Hongkyu Kang, Kwanghee Lee
Summary: Tailoring the average photopic transmittance of transparent organic solar cells (T-OSCs) has been a major challenge in building-integrated photovoltaic applications. This study demonstrates the use of a tungsten oxide-based multilayer as a highly conductive and transparent top electrode, leading to high efficiency and transparency in T-OSCs.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Dongfan Li, Ning An, Kai Tan, Yurong Ren, Hong Wang, Shengtao Li, Qian Deng, Jianwei Song, Laju Bu, Guanghao Lu
Summary: The conversion of the n-type semiconductor C-8-PTCDI into C-8-PTCDI (D) electrets enhances the charge density and trap energy level, resulting in lower operation voltage and energy consumption of devices based on n-type electrets.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Palanisamy Rajakannu, Woochan Lee, Sanghoon Park, Hyung Suk Kim, Hanif Mubarok, Min Hyung Lee, Seunghyup Yoo
Summary: In this study, phenylpyridazine-based bidentate ligands were synthesized and used for the preparation of dinuclear Pt(II) complexes. The complexes exhibited intense emissions in the NIR region, high photoluminescence quantum yields, and short phosphorescence decay lifetimes. The functional groups or atoms in the ligands played crucial roles in the formation of emitters with significantly shortened Pt center dot center dot center dot Pt distances. The resulting non-doped NIR OLEDs showed good electroluminescence performance.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Environmental
Young Hoon Lee, Woochan Lee, Taehwan Lee, Jaehoon Jung, Seunghyup Yoo, Min Hyung Lee
Summary: The design of robust TADF emitters is crucial for efficient and stable blue TADF-OLEDs. This study presents boron-based blue TADF compounds with a spiro-type boron acceptor and DPAC or sAC donors. The compounds exhibit short-lived delayed fluorescence and fast reverse intersystem crossing, leading to high-efficiency blue TADF-OLEDs with maximum EQEs over 30%. The device with the fully spiro 2 achieves a state-of-the-art EQEmax of 36.4% and a suppressed efficiency roll-off, highlighting the synergistic effect between the spiro-structure and the B-heterotriangulene acceptor skeleton.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Kiseki Kanazawa, Kirill Bulgarevich, Kohsuke Kawabata, Kazuo Takimiya
Summary: In this study, the synthesis and characterization of a previously unexplored structure, thieno[3 '',2 '':4 ',5 ']thieno[2 ',3 '-d]thieno[2,3-b]thiophene (i4TA), and its derivatives were carried out. The i4TA framework was found to have several different features compared to the commonly used building block, 4TA. The i4TA derivatives tended to crystallize into a promising π-stacking structure for high-mobility organic semiconductors.
CHEMISTRY OF MATERIALS
(2023)
Article
Nutrition & Dietetics
Hyuk Joo Lee, Seunghyup Yoo, Jung Kyung Hong, Jun Seok Ahn, Eunyoung Lee, Hanul Moon, Sunhyoung Koo, Tae Kim, Jaehyeok Park, In-Young Yoon
Summary: This study found that a prototype wearable LED UVB device was effective in improving serum 25-hydroxyvitamin D levels, with an average production of 0.031 ng/mL of vitamin D per 1 cm² of skin area.
EUROPEAN JOURNAL OF CLINICAL NUTRITION
(2023)
Article
Energy & Fuels
Shashi B. B. Srivastava, Ramakant Sharma, Divambal Appavoo, Bimlesh Lochab, Sangin Hahn, Seunghyup Yoo, Samarendra P. P. Singh
Summary: A hybrid thin film, (PC61BM-ZnO)(DEZ), is proposed as a cathode buffer layer for organic solar cells. The thin film can be deposited via a one-step solution-processable method and requires low annealing temperatures. Compared to conventional ZnO thin films, the devices with (PC61BM-ZnO)(DEZ) as a buffer layer show improved performance.
Article
Materials Science, Multidisciplinary
Ji Hun Choi, Chan Woo Park, Bock Soon Na, Jong-Heon Yang, Jeho Na, Jae-Eun Pi, Hee-Ok Kim, Chi-Sun Hwang, Seunghyup Yoo
Summary: Highly-stable molybdenum/aluminum (Mo/Al) bilayered electrodes are promising for use in stretchable electronics. The serpentine-shaped Mo/Al bilayer electrode can operate with up to 220% elongation without resistance change. By inserting Mo underneath the Al layer, the issue of Al penetration into polyimide (PI) can be overcome, resulting in robust and highly conductive stretchable electrodes. The fabricated devices, which are stretchable thin-film transistor arrays, show stable performance even under highly stretched conditions.
JOURNAL OF INFORMATION DISPLAY
(2023)
Article
Optics
Chanhyung Park, Jeongmin Shin, Sanmun Kim, Songju Lee, Juho Park, Jaehyeok Park, Sehong Park, Seunghyup Yoo, Min Seok Jang
Summary: Researchers propose a new simulation method, called the diffraction matrix method (DMM), that accurately predicts the optical characteristics of periodically corrugated OLEDs with significantly faster calculation speed. The method decomposes the light emitted by a dipolar emitter into plane waves and tracks the diffraction behavior using diffraction matrices. The calculated optical parameters show quantitative agreement with those predicted by the finite-difference time-domain (FDTD) method. Furthermore, the method evaluates the wavevector-dependent power dissipation of a dipole and identifies the loss channels inside OLEDs in a quantitative manner.
Article
Nanoscience & Nanotechnology
Junho Kim, Eungjun Kim, Jaehyeok Park, Jinouk Song, Subon Kim, Hanul Moon, Seunghyup Yoo
Summary: This study proposes a new type of ultrathin substrate embedded with an inverted microlens array (IMLA) for highly efficient foldable OLEDs. The IMLA enables OLEDs to be bent at a sub-100 μm bending radius while maintaining high light outcoupling efficiency. The potential effects of optical diffraction and the local modulation of strain and stress in ultrathin devices are carefully analyzed, and the proposed OLEDs achieve a maximum external quantum efficiency of 58% without optical side effects, withstanding 10,000 trials of repeated folding tests at a bending radius of 50 μm.
Article
Chemistry, Multidisciplinary
Hyeonwook Chae, Yongjin Park, Yehhyun Jo, Yongmin Jeon, Hyunjoo Jenny Lee, Seunghyup Yoo, Kyung Cheol Choi
Summary: Optoelectronics devices utilizing OLEDs are promising platforms for healthcare applications, particularly wearable visual stimulus systems for sleep disorder intervention. This study proposes two improvements for TrOLEDs, including a high refractive index zinc sulfide layer and an ultra-thin silver cathode, achieving a luminous transmittance of 91%. By introducing a doping process to the electron transport layer, TrOLEDs with high transmittance can achieve a lifetime comparable to control OLEDs. A preclinical model using blue light is suggested to modulate sleep patterns, showing a reduction in non-rapid-eye-movement sleep duration in mice. These TrOLEDs offer convenience and potential for modulating sleep disorders such as insomnia and narcolepsy-cataplexy.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Multidisciplinary Sciences
Hyung Suk Kim, Hyung Jin Cheon, Donggyun Lee, Woochan Lee, Junho Kim, Yun-Hi Kim, Seunghyup Yoo
Summary: A new boron-based compound o-Tol-nu-DABNA-Me with sterically hindered peripheral phenyl groups was proposed to reduce intermolecular interactions and suppress excimer formation, resulting in a less sensitive narrowband emission to concentration. Deep-blue OLEDs with y-coordinate of 0.12 and a full width at half maximum of 18 nm were achieved with a maximum external quantum efficiency (EQE) of approximately 33%. By adopting a hyperfluorescent architecture, the OLED performance was further improved to an EQE of 35.4% with mitigated efficiency roll-off, demonstrating the significant potential of this method for energy-efficient deep-blue OLEDs.
Article
Chemistry, Multidisciplinary
Haechang Lee, Ramakant Sharma, Sehwan Park, Zhenan Bao, Hanul Moon, Seunghyup Yoo
Summary: A flexible pressure sensor based on a texturing-free piezocapacitive layer is proposed, which utilizes ion infiltration for electrical-double-layer modulation and exhibits excellent mechanical durability and linear response over a wide pressure range.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Physical
Kohsuke Kawabata, Kazuo Takimiya
Summary: By synthesizing and studying D-A-D triad molecules using the donor-acceptor approach, it was found that a highly electron deficient acceptor unit lowers the LUMO energy level, reduces the optical energy gap, and maintains low-lying frontier orbital energy levels. Two isoelectronic series incorporating different chalcogen atoms were investigated, and the oxygen analogues exhibited superior carrier transport properties compared to the sulfur and selenium analogues.
CHEMISTRY OF MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Alexandre Bachelet, Sophie Fasquel, Jean-Michel Rampnoux, Gediminas Jonusauskas, Kazuo Takimiya, Lionel Hirsch, Mathias Perrin, Mamatimin Abbas
Summary: Using a single emissive layer, this study achieved color tuning within a wide visible light range (from blue to red) in organic light emitting transistors. The color tuning does not affect the optical turn-on voltages and significantly enhanced external quantum efficiencies are observed for devices with a thick emissive layer. The wide range of color tunability is mainly due to an outcoupling effect through the Fabry-Perot cavity.
Article
Chemistry, Multidisciplinary
Young Hoon Lee, Jeoungmin Ji, Thi Quyen Tran, Taehwan Lee, Jaehoon Jung, Youngil Lee, Seunghyup Yoo, Min Hyung Lee
Summary: This study reports two TADF emitters with high horizontal transition dipole orientation and molecular rigidity, which exhibit excellent performance and high quantum efficiency in deep-blue emission.
MATERIALS CHEMISTRY FRONTIERS
(2023)
