Article
Chemistry, Physical
Francesca Pallini, Sara Mattiello, Marco Cassinelli, Pietro Rossi, Sara Mecca, Wen Liang Tan, Mauro Sassi, Guglielmo Lanzani, Christopher R. McNeill, Mario Caironi, Luca Beverina
Summary: This study reveals the key factors in molecular doping of conjugated polymers, especially in n-type doping. It found that a decomposition product can act as a nucleating agent for a new crystalline phase, enhancing the electrical conductivity of the doped polymer films.
ACS APPLIED ENERGY MATERIALS
(2022)
Review
Chemistry, Physical
Marco Roberto Cavallari, Loren Mora Pastrana, Carlos Daniel Flecha Sosa, Alejandra Maria Rodriguez Marquina, Jose Enrique Eirez Izquierdo, Fernando Josepetti Fonseca, Cleber Alexandre de Amorim, Leonardo Giordano Paterno, Ioannis Kymissis
Summary: Organic thin-film transistors (OTFTs) as gas sensor devices have shown remarkable performance in detecting important target analytes, with electronic properties modulated by molecular engineering. This manuscript provides a comprehensive review on the working principle of OTFTs for gas sensing, including device fabrication methods and recent applications of main organic semiconductors, alongside an outlook toward the future of this exciting technology.
Article
Materials Science, Multidisciplinary
Matthias Zwadlo, Jakub Hagara, Giuliano Duva, Jan Hagenlocher, Alexander Gerlach, Ivan Zaluzhnyy, Martin Hodas, Alexander Hinderhofer, Peter Siffalovic, Frank Schreiber
Summary: This study investigates the thin film crystal structure of [6]phenacene and [7]phenacene deposited on silicon substrates using the OMBD method, as well as the influence of potassium deposition on [6]phenacene. Ex-situ X-ray and optical methods are employed to analyze the crystal structure and orientation of the molecules. Results show that the odd/even parity of benzene rings directly influences the phenacene thin film structure.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Chemistry, Physical
Fabio Calcinelli, Andreas Jeindl, Lukas Hoermann, Simiam Ghan, Harald Oberhofer, Oliver T. Hofmann
Summary: The structure and chemical composition of organic thin films are crucial for their properties on inorganic substrates. The substrate can significantly affect the polymorphism of the films. By studying the influence of two different substrates, Ag(111) and graphene, on para-benzoquinone, this work sheds light on the role of the substrate. First-principles calculations and machine learning are used to identify the energetically favorable structures on both substrates and investigate their electronic properties. The switch in stability between the two substrates is explained by the different charge transfer effects.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Nanoscience & Nanotechnology
Eun Goo Lee, Yong Jun Gong, Sung-Eun Lee, Hyun-Jae Na, Changik Im, Heebae Kim, Youn Sang Kim
Summary: By incorporating polyaniline (PANI) into metal oxide matrix, the electrical characteristics and stability of metal oxide thin-film transistors (TFTs) can be significantly improved.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Zeno Schumacher, Rasa Rejali, Megan Cowie, Andreas Spielhofer, Yoichi Miyahara, Peter Grutter
Summary: Inducing an inversion layer in organic semiconductors is a critical achievement for producing OFET devices, and a new pulsed bias technique is developed to characterize the dopant type of different organic material systems. This technique accurately identifies n-doping in pentacene/PTCDI heterostructure, demonstrating that nanometer-scale lateral extent and thickness are sufficient for an OFET device to operate in the inversion regime.
Article
Physics, Applied
Satoshi Takane, Yuki Noda, Naomi Toyoshima, Takafumi Uemura, Yuki Bando, Tsuyoshi Sekitani
Summary: A flexible organic thin-film transistor with gold nanowire networks as electrodes was fabricated, showing good electronic performance and mechanical durability.
APPLIED PHYSICS EXPRESS
(2022)
Review
Polymer Science
Kai-Qing Liu, Yuan-He Gu, Zheng-Ran Yi, Yun-Qi Liu
Summary: Since the introduction of diketopyrrolopyrrole (DPP)-based conjugated polymers, they have been widely studied as semiconducting materials for high-performance organic thin-film transistors (OTFTs). Significant progress has been made in molecular design, synthesis, and processing techniques, leading to impressive mobility values exceeding 10 cm(2)center dot V-1 center dot s(-1) in OTFT devices. This review provides a comprehensive summary of the advancements in DPP-based conjugated polymers for OTFTs, highlighting the importance of design strategies, synthesis methods, and solution processing. The review also briefly discusses the remaining challenges and future prospects in this field.
CHINESE JOURNAL OF POLYMER SCIENCE
(2023)
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
Chemistry, Multidisciplinary
Marco Hoeppner, Bahman Kheradmand-Boroujeni, Joern Vahland, Michael Franz Sawatzki, David Kneppe, Frank Ellinger, Hans Kleemann
Summary: The high-frequency and low-voltage operation of organic thin-film transistors (OTFTs) is crucial for the commercial success of flexible electronics. While significant progress has been made, technology maturity remains a key challenge, including scalability, integrability, and device reliability.
Article
Chemistry, Multidisciplinary
Jakob Lenz, Anna Monika Seiler, Fabian Rudolf Geisenhof, Felix Winterer, Kenji Watanabe, Takashi Taniguchi, Ralf Thomas Weitz
Summary: This study demonstrates the fabrication of liquid electrolyte gated vertical organic field effect transistors with channel lengths down to 2.4 nm, showing promising electrical characteristics and high performance. By using hexagonal boron nitride as a spacer to separate vertically aligned source and drain electrodes, the potential of organic semiconductors for future highly integrated or low power electronics is highlighted.
Article
Engineering, Electrical & Electronic
Wolfgang Rao Bodlos, Sang Kyu Park, Birgit Kunert, Soo Young Park, Roland Resel
Summary: The study found that thin films deposited at different temperatures in a specific molar ratio cocrystal system exhibit different crystal structures and transistor performance. Crystal growth is enhanced with increasing temperature, but performance decreases at higher temperatures.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Yujia Wei, Di Xue, Lianlian Ji, Jie Lu, Qi Wang, Xingyu Jiang, Yinghui Sun, Zi Wang, Lizhen Huang, Lifeng Chi
Summary: The growth of rubrene on h-BN substrate was systematically studied, revealing the role of temperature in the transition process and the epitaxy relationship between rubrene and h-BN. A precise layer-by-layer growth was achieved at high substrate temperature, demonstrating good charge transport ability.
CHINESE JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Physical
Hanleem Lee, Sora Bak, Joosung Kim, Hyoyoung Lee
Summary: The study focuses on the effects of organic dopants reactivity on MoS2 and how it influences the electrical properties of MoS2. The band state of the dopants causes a proportional shift in the threshold voltages of the field-effect transistors, while on/off current ratio and mobility are strongly influenced by the defect density depending on the reactivity of the doping reaction. Through an in-depth study on the doping reaction, a solution-processed FET and a TFT with high mobility and a relatively high on/off ratio are successfully fabricated.
Article
Chemistry, Physical
Tomas Vincze, Michal Micjan, Juraj Nevrela, Martin Donoval, Martin Weis
Summary: Organic field-effect transistors are considered the future direction for advanced photodetectors due to their unique absorption characteristics, low-cost fabrication, or compatibility with flexible substrates. However, the response time of organic phototransistors still needs to be improved.
Article
Multidisciplinary Sciences
Shu-Jen Wang, Michel Panhans, Ilia Lashkov, Hans Kleemann, Federico Caglieris, David Becker-Koch, Joern Vahland, Erjuan Guo, Shiyu Huang, Yulia Krupskaya, Yana Vaynzof, Bernd Buechner, Frank Ortmann, Karl Leo
Summary: The charge and thermoelectric transport in modulation-doped large-area rubrene thin-film crystals with different crystal phases were investigated. The results showed that modulation doping, together with high-mobility crystalline organic semiconductor films, is a previously unexplored strategy for achieving high-performance organic thermoelectrics. Theoretical studies provided insight into the energy landscape of the heterostructures and its influence on qualitative trends of the Seebeck coefficient.
Article
Chemistry, Multidisciplinary
Marco Hoeppner, Bahman Kheradmand-Boroujeni, Joern Vahland, Michael Franz Sawatzki, David Kneppe, Frank Ellinger, Hans Kleemann
Summary: The high-frequency and low-voltage operation of organic thin-film transistors (OTFTs) is crucial for the commercial success of flexible electronics. While significant progress has been made, technology maturity remains a key challenge, including scalability, integrability, and device reliability.
Article
Nanoscience & Nanotechnology
Adara Babuji, Alba Cazorla, Eduardo Solano, Carsten Habenicht, Hans Kleemann, Carmen Ocal, Karl Leo, Esther Barrena
Summary: Charge-transfer complexes play a key role in surface doping in organic field-effect transistors. Sequential deposition allows for the formation and evolution of a cocrystalline structure without compromising the integrity of the thin film structure, resulting in improved device performance compared to codeposition doping.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Tianyu Tang, Preetam Dacha, Katherina Haase, Joshua Kress, Christian Haenisch, Jonathan Perez, Yulia Krupskaya, Alexander Tahn, Darius Pohl, Sebastian Schneider, Felix Talnack, Mike Hambsch, Sebastian Reineke, Yana Vaynzof, Stefan C. B. Mannsfeld
Summary: This work describes an eco-friendly and streamlined method for preparing thin-film transistors (TFTs) using metal oxide (MO) semiconductors. The process involves a pure water-solution blade-coating technique with a low thermal budget. The resulting devices exhibit high electrical performance, with average field effect mobility ranging from 10.7 to 13.8 cm(2) V-1 s(-1), excellent on/off ratio (>10(6)), and threshold voltage close to 0 V.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Shu-Jen Wang, Anton Kirch, Michael Sawatzki, Tim Achenbach, Hans Kleemann, Sebastian Reineke, Karl Leo
Summary: Conventional organic optoelectronic devices have low carrier mobility due to disorder. This study presents monolithic integrated triclinic crystal rubrene light-emitting diodes (LEDs) with engineered functional additives. The crystalline LEDs show superior charge transport, operational stability, and long-term stability. However, the crystalline phase reduces the overall performance compared to amorphous rubrene in terms of exciton dynamics and annihilation rates. The potential applications of rubrene and/or its derivatives crystalline films for improving the performance of organic and hybrid optoelectronic devices are discussed.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Michael Sawatzki-Park, Shu-Jen Wang, Hans Kleemann, Karl Leo
Summary: Organic semiconductors have brought about many new electronic applications with their flexibility, low-cost manufacturing, and biocompatibility. However, most current devices made of highly disordered thin-films result in poor transport properties and reduced device performance. In this article, techniques for preparing highly ordered thin-films of organic semiconductors are discussed, aiming to achieve fast and efficient devices as well as novel device types. The focus is on thermal treatment of amorphous layers of small molecules to create crystalline thin-films, which have shown excellent lateral and vertical mobilities and can be electrically doped for high n- and p-type conductivities. By integrating these highly ordered layers into specialized devices, such as high-frequency diodes or bipolar transistors, exciting possibilities for organics can be realized.
Article
Chemistry, Multidisciplinary
Raufar Shameem, Lukas M. Bongartz, Anton Weissbach, Hans Kleemann, Karl Leo
Summary: The ability of organic electrochemical transistors (OECTs) to combine ionic and electronic transport with large volumetric capacitance makes them ideal for bioelectronic applications. The use of solid electrolytes based on ionic liquids extends their applicability and enables large-area printable production. However, OECTs with solid electrolytes often exhibit pronounced hysteresis in the transfer curve, which needs to be understood for accurate characterization and reliable applications.
APPLIED SCIENCES-BASEL
(2023)
Article
Nanoscience & Nanotechnology
Juan Wang, Amric Bonil, Joern Vahland, Hans Kleemann
Summary: Due to their nm-range channel length, vertical organic transistors are gaining scientific interest to overcome the frequency limitations of lateral organic transistors. Particularly, vertical organic permeable base transistors (OPBTs) show excellent electrical performance and potential applications in high-frequency logic circuits, display driving circuits, and light-emitting devices. In this study, the extended exposure of p-type OPBTs to ambient air during fabrication was found to have a positive effect on electrical performance, improving device yield to 100%. Oxygen diffuses into the semiconductor layer, interacts with the base electrode, creates pinholes in the base, and forms an insulator layer, enhancing device performance. The positive effect of air exposure can be utilized to optimize p-type OPBTs, providing a simple approach for constructing high-performance p-type OPBTs and complementary circuits.
Article
Chemistry, Multidisciplinary
Zongbao Zhang, Ran Ji, Xiangkun Jia, Shu-Jen Wang, Marielle Deconinck, Elena Siliavka, Yana Vaynzof
Summary: This study demonstrates the successful fabrication of compact ultra-thin CsPbI3 perovskite films using a co-evaporation process. The films with a thickness of 10 nm exhibit high power conversion efficiency in a device structure of glass/ITO/PTAA/perovskite/PCBM/BCP/Al/Ag.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Anton Weissbach, Matteo Cucchi, Hsin Tseng, Karl Leo, Hans Kleemann
Summary: Organic electrochemical transistors (OECTs) are promising for bioelectronics and neuromorphic computing, but their integration into real-world applications is hindered by a lack of understanding of their complex operation. This study reveals a peculiar behavior of integrated OECTs in their electrolytic environment, called electrochemical electrode coupling (EEC), which significantly affects device and circuit performance. A physical model is developed to describe this effect and experimental data substantiate it, highlighting the crucial role of the gate electrode. The study also explores the impact of electrode/channel overlap on output saturation and demonstrates ways to minimize its detrimental effect on circuit performance.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Katherina Haase, Felix Talnack, Shabnam Donnhaeuser, Alexander Tahn, Markus Loeffler, Mike Hambsch, Stefan C. B. Mannsfeld
Summary: In this paper, we demonstrate the fabrication of sub-micrometer channel devices using a simple inclined thermal evaporation approach. This method allows for the production of electrodes with distances below 100 nm, which is compatible with solution-based fabrication methods commonly used for high-mobility organic semiconductor films or high-capacitance polymer gate dielectrics. By directly defining the contacts through thermal evaporation without the need for expensive masks or lithography techniques, this approach enables simple lab-scale assessment of material combinations for high-performance organic transistors through direct access to sub-micrometer channel device characteristics. The paper focuses on the fabrication method, presents example devices with sub-micrometer channel lengths, and discusses the potential applications of this methodology as a lab-scale test vehicle for OFET development.
ORGANIC ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
Tommy Meier, Yeohoon Yoon, Laura Teuerle, Ali Solgi, Karl Leo, Hans Kleemann
Summary: This research presents a hybrid fabrication method for organic electrochemical transistors by combining orthogonal photolithography and inkjet printing, which enables high uniformity and reliability. The study explores the influence of the resolution of each process on uniformity and investigates the advantages of this process for device scaling and circuit integration.
MRS COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Xiangkun Jia, Lorenzo Soprani, Giacomo Londi, Seyed Mehrdad Hosseini, Felix Talnack, Stefan Mannsfeld, Safa Shoaee, Dieter Neher, Sebastian Reineke, Luca Muccioli, Gabriele D'Avino, Koen Vandewal, David Beljonne, Donato Spoltore
Summary: This article investigates the impact of interfacial energetics and molecular arrangement on charge separation and radiative recombination in organic solar cells. It finds that an ordered molecular packing at the donor-acceptor interface is beneficial for efficient charge separation and higher fill factors in photovoltaic devices.
MATERIALS HORIZONS
(2023)
Article
Engineering, Electrical & Electronic
Shu-Jen Wang, Alexander Palatnik, Markas Sudzius, Felix Talnack, Luisa Barba, Zongbao Zhang, Darius Pohl, Ilia Lashkov, Christian Haenisch, Anton Kirch, Jorn Vahland, Marius Otte, Hans Kleemann, Stefan C. B. Mannsfeld, Sebastian Reineke, Karl Leo
Summary: This study demonstrates the preparation of BSB-Cz thin-film crystals using a simple vacuum deposition method followed by thermal annealing. The resulting crystalline neat films exhibit high photoluminescence quantum yield and superior optical stability, providing a potential route for advancing organic laser devices.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
