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Ananth Dodabalapur - One of the best experts on this subject based on the ideXlab platform.
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inkjet Printed Circuits based on ambipolar and p type carbon nanotube thin film transistors
Scientific Reports, 2017Co-Authors: Bongjun Kim, Michael L Geier, Mark C Hersam, Ananth DodabalapurAbstract:Ambipolar and p-type single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs) are reliably integrated into various complementary-like Circuits on the same substrate by inkjet printing. We describe the fabrication and characteristics of inverters, ring oscillators, and NAND gates based on complementary-like Circuits fabricated with such TFTs as building blocks. We also show that complementary-like Circuits have potential use as chemical sensors in ambient conditions since changes to the TFT characteristics of the p-channel TFTs in the circuit alter the overall operating characteristics of the circuit. The use of Circuits rather than individual devices as sensors integrates sensing and signal processing functions, thereby simplifying overall system design.
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inkjet Printed Circuits on flexible and rigid substrates based on ambipolar carbon nanotubes with high operational stability
ACS Applied Materials & Interfaces, 2015Co-Authors: Bongjun Kim, Michael L Geier, Mark C Hersam, Ananth DodabalapurAbstract:Inkjet Printed ambipolar transistors and Circuits with high operational stability are demonstrated on flexible and rigid substrates employing semiconducting single-walled carbon nanotubes (SWCNTs). All patterns, which include electrodes, semiconductors, and vias, are realized by inkjet printing without the use of rigid physical masks and photolithography. An Al2O3 layer deposited on devices by atomic layer deposition (ALD) transforms p-type SWCNT thin-film transistors (TFTs) into ambipolar SWCNT TFTs and encapsulates them effectively. The ambipolar SWCNT TFTs have balanced electron and hole mobilities, which facilitates their use in multicomponent Circuits. For example, a variety of logic gates and ring oscillators are demonstrated based on the ambipolar TFTs. The three-stage ring oscillator operates continuously for longer than 80 h under ambient conditions with only slight deviations in oscillation frequency. The successful demonstration of ambipolar devices by inkjet printing will enable a new class of Circuits that utilize n-channel, p-channel, and ambipolar circuit components.
Chingping Wong - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation analysis of flexible Printed Circuits under bending conditions
International Conference on Electronic Packaging Technology, 2021Co-Authors: Yongchao Liu, Haozhe Wang, Chao Peng, Xu Long, Rong Sun, Chingping WongAbstract:Flexible Printed Circuits (FPC) have been extensively used in daily life. It is inevitable to perform high-frequency reciprocating bending when using FPC., which induces deviation of the circuit board structure., separation of the adhesive layer and finally damage of the device. To solve the problem., it is suggested to change the FPC laminate design and adjust the internal structure and materials of the FPC so that the stress of the Cu layer is concentrated in the neutral layer during the bending process of the FPC and reducing the strain of the adhesive layer. In this paper., we systematically investigate the impact factors to the bending process of the FPC by using the finite element analysis (FEA). The characterized factors include the stacked structure and elastic modulus of each layer., the thickness of the glue/Cu layer., and the bending radius of the FPC. We find that different stack structures drastically influence the position of the stress neutral layer; the stress increases as the elastic modulus of material increases., but decreases with reducing the adhesive layer. Whereas., the elastic modulus of the material and the thickness of the adhesive layer have little effect on the position of the stress neutral layer of the FPC. Furthermore., the increasement in the thickness of the Cu layer increases the stress of the FPC and moving the position of the stress neutral layer downward. As the bending radius increases., the stress on FPC decreases., while the position of the neutral layer hardly changes. We also find that the smaller elastic modulus and thinner glue/Cu layer reduce the stress of the Cu layer. These simulation results provide a guidance for the design of structures and material selection of FPC., which may help solving the mechanical problems during the bending process.
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flexible copper wires through galvanic replacement of zinc paste a highly cost effective technology for wiring flexible Printed Circuits
Journal of Materials Chemistry C, 2015Co-Authors: Jingping Liu, Chingping Wong, Cheng Yang, Feiyu Kang, Peichao Zou, Rui Yang, Binghe Xie, Ziyin LinAbstract:Conventional electronic circuit wiring methods involve subtractive processes such as etching the copper foils, and thus are inefficient and cause serious environmental problems. Printed electronics technology is expected to be more environmentally benign and have lower cost, due to its additive characteristics. In this paper, we present a simple and efficient strategy to fabricate high performance copper metal fine Circuits by a galvanic replacement deposition method. Zinc nanoparticles filled epoxy resin paste is Printed onto the substrate film as the seed layer; with a subsequent simple galvanic replacement reaction between Zn and Cu2+, we can obtain a conductive Cu layer that can be further thickened by electroplating. The as-prepared Circuits show bulk Cu conductivity, excellent flexibility, adhesion strength and pattern resolution. By adjusting the processing parameters, this technology is suitable for various practical applications, such as flexible circuit boards, RFID tags, touch panels, membrane switches, and photovoltaics, making it a promising solution for low-cost and environmentally friendly fabrication for flexible electronic devices.
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towards practical application of paper based Printed Circuits capillarity effectively enhances conductivity of the thermoplastic electrically conductive adhesives
Scientific Reports, 2015Co-Authors: Sum Wai Chiang, Wei Lin, Cheng Yang, Jingping Liu, Xiaoya Cui, Feiyu Kang, Chingping WongAbstract:Direct printing nanoparticle-based conductive inks onto paper substrates has encountered difficulties e.g. the nanoparticles are prone to penetrate into the pores of the paper and become partially segmented, and the necessary low-temperature-sintering process is harmful to the dimension-stability of paper. Here we prototyped the paper-based circuit substrate in combination with Printed thermoplastic electrically conductive adhesives (ECA), which takes the advantage of the capillarity of paper and thus both the conductivity and mechanical robustness of the Printed Circuitsweredrastically improved without sintering process. For instance, the electrical resistivity of the ECA specimen on a pulp paper (6 × 10−5Ω·cm, with 50 wt% loading of Ag) was only 14% of that on PET film than that on PET film. This improvement has been found directly related to the sizing degree of paper, in agreement with the effective medium approximation simulation results in this work. The thermoplastic nature also enables excellent mechanical strength of the Printed ECA to resist repeated folding. Considering the generality of the process and the wide acceptance of ECA technique in the modern electronic packages, this method may find vast applications in e.g. circuit boards, capacitive touch pads, and radio frequency identification antennas, which have been prototyped in the manuscript.
Daniel C Frisbie - One of the best experts on this subject based on the ideXlab platform.
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aerosol jet Printed sub 2 v complementary Circuits constructed from p and n type electrolyte gated transistors
Advanced Materials, 2014Co-Authors: Kihyon Hong, Yong Hyun Kim, Se Hyun Kim, Wei Xie, Chris H Kim, Daniel C FrisbieAbstract:Printed low-voltage complementary inverters based on electrolyte gated transistors are demonstrated. The Printed complementary inverters showed gain of 18 and power dissipation below 10 nW. 5-stage ring oscillators operate at 2 V with an oscillation frequency of 2.2 kHz, corresponding to stage delays of less than 50 μs. The Printed Circuits exhibit good stability under continuous dynamic operation.
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Printed sub 2 v gel electrolyte gated polymer transistors and Circuits
Advanced Functional Materials, 2010Co-Authors: Yu Xia, Chris H Kim, Wei Zhang, Jeong Ho Cho, Michael J Renn, Daniel C FrisbieAbstract:The fabrication and characterization of Printed ion-gel-gated poly(3-hexylthiophene) (P3HT) transistors and integrated Circuits is reported, with emphasis on demonstrating both function and performance at supply voltages below 2 V. The key to achieving fast sub-2 V operation is an unusual gel electrolyte based on an ionic liquid and a gelating block copolymer. This gel electrolyte serves as the gate dielectric and has both a short polarization response time ( 10 μF cm -2 ), which leads simultaneously to high output conductance (>2 mS mm -1 ), low threshold voltage (<1 V) and high inverter switching frequencies (1-10 kHz). Aerosol-jet-Printed inverters, ring oscillators, NAND gates, and flip-flop Circuits are demonstrated. The five-stage ring oscillator operates at frequencies up to 150 Hz, corresponding to a propagation delay of 0.7 ms per stage. These Printed gel electrolyte gated Circuits compare favorably with other reported Printed Circuits that often require much larger operating voltages. Materials factors influencing the performance of the devices are discussed.
Bongjun Kim - One of the best experts on this subject based on the ideXlab platform.
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inkjet Printed Circuits based on ambipolar and p type carbon nanotube thin film transistors
Scientific Reports, 2017Co-Authors: Bongjun Kim, Michael L Geier, Mark C Hersam, Ananth DodabalapurAbstract:Ambipolar and p-type single-walled carbon nanotube (SWCNT) thin-film transistors (TFTs) are reliably integrated into various complementary-like Circuits on the same substrate by inkjet printing. We describe the fabrication and characteristics of inverters, ring oscillators, and NAND gates based on complementary-like Circuits fabricated with such TFTs as building blocks. We also show that complementary-like Circuits have potential use as chemical sensors in ambient conditions since changes to the TFT characteristics of the p-channel TFTs in the circuit alter the overall operating characteristics of the circuit. The use of Circuits rather than individual devices as sensors integrates sensing and signal processing functions, thereby simplifying overall system design.
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inkjet Printed Circuits on flexible and rigid substrates based on ambipolar carbon nanotubes with high operational stability
ACS Applied Materials & Interfaces, 2015Co-Authors: Bongjun Kim, Michael L Geier, Mark C Hersam, Ananth DodabalapurAbstract:Inkjet Printed ambipolar transistors and Circuits with high operational stability are demonstrated on flexible and rigid substrates employing semiconducting single-walled carbon nanotubes (SWCNTs). All patterns, which include electrodes, semiconductors, and vias, are realized by inkjet printing without the use of rigid physical masks and photolithography. An Al2O3 layer deposited on devices by atomic layer deposition (ALD) transforms p-type SWCNT thin-film transistors (TFTs) into ambipolar SWCNT TFTs and encapsulates them effectively. The ambipolar SWCNT TFTs have balanced electron and hole mobilities, which facilitates their use in multicomponent Circuits. For example, a variety of logic gates and ring oscillators are demonstrated based on the ambipolar TFTs. The three-stage ring oscillator operates continuously for longer than 80 h under ambient conditions with only slight deviations in oscillation frequency. The successful demonstration of ambipolar devices by inkjet printing will enable a new class of Circuits that utilize n-channel, p-channel, and ambipolar circuit components.
M Guglielmi - One of the best experts on this subject based on the ideXlab platform.
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multimode equivalent network for boxed multilayer arbitrary planar Circuits
IEEE Transactions on Microwave Theory and Techniques, 2020Co-Authors: Celia Gomez Molina, Fernando Daniel Quesada Pereira, Alejandro Alvarez Melcon, Vicente E Boria, Stephan Marini, Miguel A Sanchezsoriano, M GuglielmiAbstract:The multimode equivalent network (MEN) formulation has been originally developed for the efficient and accurate analysis of waveguide devices. In this article, we extend the use of the MEN to the analysis of zero-thickness, planar Printed Circuits in a metallic enclosure. The formulation is developed for metallic areas of arbitrary shape and includes both internal and external ports in the transverse plane to model connections to external components, and coaxial input/output ports. The boundary integral resonant mode expansion (BI-RME) method is used for the analysis of the arbitrary shape metallizations. On this basis, shielded multilayered microstrip Circuits of complex geometry are analyzed in the common frame of the MEN technique. To validate the theoretical formulation, several boxed microstrip structures are analyzed, including multilayered configurations with several metallization interfaces, showing good agreement with respect to both other commercial tools, and measurements.
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rigorous multimode equivalent network representation of multilayer planar Circuits
IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization, 2018Co-Authors: Celia Gomez Molina, Fernando Daniel Quesada Pereira, Alejandro Alvarez Melcon, Stephan Marini, Miguel A Sanchezsoriano, Vicente Enrique Boria Esbert, M GuglielmiAbstract:The objective of this paper is to extend the use of the Multimode Equivalent Network formulation, originally developed to analyze waveguide junctions, to the analysis of planar Circuits that include arbitrary rectangular Printed, zero thickness metallizations together with internal and external ports in the transverse plane. The theoretical derivations lead to an accurate and computationally efficient tool for the analysis of boxed, multilayer microwave Printed Circuits. In addition to theory, the tool developed is used here to analyze two practical examples: a dual-bandpass and a 4-pole bandpass boxed microstrip filters. Good agreement with respect to commercial software tools and measurements is shown, thereby fully validating the theoretical formulation.