The Influence of the Socratic Tradition on Cambridge Practice and Its Implication on Chinese Higher Education

This paper presents the use of polyelectrolyte-decorated amyloid fibrils as gate electrolyte in electrochromic electrochemical transistors. Conducting polymer alkoxysulfonate poly(3,4-ethylenedioxythiophene) (PEDOT-S) and luminescent conjugate polymer poly(thiophene acetic acid) (PTAA) are utilized to decorate insulin amyloid fibrils for gating lateral poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) electrochemical transistors. In this comparative work, four gate electrolytes are explored, including the polyelectrolytes and their amyloid-fibril complexes. The discrimination of transistor behaviors with different gate electrolytes is understood in terms of an electrochemical mechanism. The combination of luminescent polymers, biomolecules and electrochromic transistors enables multi functions in a single device, for example, the color modulation in monochrome electrochromic display, as well as biological sensing/labeling.Funding Agencies|"OPEN" project at the Center of Organic Electronics (COE) at Linkoping University, Sweden||Strategic Research Foundation SSF||</p

An electrospun fiber phototransistor by the conjugated polymer poly†2-methoxy-5-"2'-ethylhexyloxy…-1,4-phenylene-vinylene‡

We investigate the photoresponse of field-effect transistors based on conjugated polymer electrospun fibers. The electrical performances of single fiber transistors are controlled by modulating the channel conductivity under white light illumination. We demonstrate a photoresponsivity up to 100 mA/W for a 500-nm channel width fiber phototransistor illuminated by an intensity of 9.6 mW/cm2. Studying the photoresponse switching cycles evidences that the photocurrent relaxation time can be reduced down to about 40 s by increasing the fiber surface-to-volume ratio

Numerical Analysis of Spreading Process of Ellipsoidal Spraying Droplet Impacting on Superhydrophobic Surface

Agricultural spray deposition is especially important for pesticide application because low efficiency can lead to environmental pollution, poor biological efficiency and economic loss. The deposition of pesticide spray on the leave surfaces is related to the impact kinetic behavior of droplets. But after considering the deformation of the droplet, how impingement will affect the deposition is an interesting research. In this study, a superhydrophobic surface was used to replace the plant surface that the pesticide droplets may affect. An interface tracking method was proposed to characterize the impingement dynamics behaviors of different ellipsoid droplets impacting on the surface. The maximum spreading coefficient and time of ellipsoidal droplets increased with the raise of their size. A lower sized droplet has a faster spreading rate, while the center of a higher sized droplet is thinner. As the velocity of pesticide increases, maximum spreading coefficient of droplet increases with a decrease in the maximum spreading time of droplet. The simulation results can contribute to provide theoretical basis for improving spray efficiency

Single light-emitting polymer nanofiber field-effect transistors

We report on single nanofiber field-effect transistors made by the light-emitting polymer, poly(2-methoxy-5-(2-ethylhexoxy)-1,4-phenylenevinylene). We measure electrical performances comparable to or better than those of thin-film transistors by the same organic semiconductor, due to the molecular alignment induced by electrospinning, such as hole mobility of the order of 10−3 cm2 V−1 s−1 and on/off current ratios up to 780. In addition, we observe controllable photoluminescence intensity quenching by varying the gate voltage up to −40 V with device operation in the luministor mode. Single light-emitting polymer nanofiber transistors coupling electrical and optical functionalities open the way towards low cost and flexible one-dimensional switches and nanofiber-based light-emitting transistors

Low-power/high-gain flexible complementary circuits based on printed organic electrochemical transistors

The ability to accurately extract low-amplitude voltage signals is crucial in several fields, ranging from single-use diagnostics and medical technology to robotics and the Internet of Things. The organic electrochemical transistor, which features large transconductance values at low operation voltages, is ideal for monitoring small signals. Its large transconductance translates small gate voltage variations into significant changes in the drain current. However, a current-to-voltage conversion is further needed to allow proper data acquisition and signal processing. Low power consumption, high amplification, and manufacturability on flexible and low-cost carriers are also crucial and highly anticipated for targeted applications. Here, we report low-power and high-gain flexible circuits based on printed complementary organic electrochemical transistors (OECTs). We leverage the low threshold voltage of both p-type and n-type enhancement-mode OECTs to develop complementary voltage amplifiers that can sense voltages as low as 100 $\mu$V, with gains of 30.4 dB and at a power consumption < 2.7 $\mu$W (single-stage amplifier). At the optimal operating conditions, the voltage gain normalized to power consumption reaches 169 dB/$\mu$W, which is > 50 times larger than state-of-the-art OECT-based amplifiers. In a two-stage configuration, the complementary voltage amplifiers reach a DC voltage gain of 193 V/V, which is the highest among emerging CMOS-like technologies operating at supply voltages below 1 volt. Our findings demonstrate that flexible complementary circuits based on printed OECTs define a power-efficient platform for sensing and amplifying low-amplitude voltage signals in several emerging beyond-silicon applications

Low-Power/High-Gain Flexible Complementary Circuits Based on Printed Organic Electrochemical Transistors

The ability to accurately extract low-amplitude voltage signals is crucial in several fields, ranging from single-use diagnostics and medical technology to robotics and the Internet of Things (IoT). The organic electrochemical transistor (OECT), which features large transconductance values at low operating voltages, is ideal for monitoring small signals. Here, low-power and high-gain flexible circuits based on printed complementary OECTs are reported. This work leverages the low threshold voltage of both p-type and n-type enhancement-mode OECTs to develop complementary voltage amplifiers that can sense voltages as low as 100 \ub5V, with gains of 30.4\ua0dB and at a power consumption of 0.1–2.7 \ub5W (single-stage amplifier). At the optimal operating conditions, the voltage gain normalized to power consumption reaches 169\ua0dB \ub5W−1, which is &gt;50\ua0times larger than state-of-the-art OECT-based amplifiers. In a monolithically integrated two-stage configuration, these complementary voltage amplifiers reach voltage gains of 193\ua0V/V, which are among the highest for emerging complementary metal-oxide-semiconductor-like technologies operating at supply voltages below 1 V. These flexible complementary circuits based on printed OECTs define a new power-efficient platform for sensing and amplifying low-amplitude voltage signals in several emerging beyond-silicon applications

Synergistic Effect of Multi-Walled Carbon Nanotubes and Ladder-Type Conjugated Polymers on the Performance of N-Type Organic Electrochemical Transistors

Organic electrochemical transistors (OECTs) have the potential to revolutionize the field of organic bioelectronics. To date, most of the reported OECTs include p-type (semi-)conducting polymers as the channel material, while n-type OECTs are yet at an early stage of development, with the best performing electron-transporting materials still suffering from low transconductance, low electron mobility, and slow response time. Here, the high electrical conductivity of multi-walled carbon nanotubes (MWCNTs) and the large volumetric capacitance of the ladder-type π-conjugated redox polymer poly(benzimidazobenzophenanthroline) (BBL) are leveraged to develop n-type OECTs with record-high performance. It is demonstrated that the use of MWCNTs enhances the electron mobility by more than one order of magnitude, yielding fast transistor transient response (down to 15\ua0ms) and high μC* (electron mobility 7 volumetric capacitance) of about 1 F cm−1\ua0V−1 s−1. This enables the development of complementary inverters with a voltage gain of &gt;16 and a large worst-case noise margin at a supply voltage of &lt;0.6\ua0V, while consuming less than 1 \ub5W of power

Stereoselective lithiation of N-Boc cyclic amines in natural product synthesis

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Mixed ion-electron transport in organic electrochemical transistors

Organic electrochemical transistors (OECTs) have shown great promise in a variety of applications ranging from digital logic circuits to biosensors and artificial synapses for neuromorphic computing. The working mechanism of OECTs relies on the mixed transport of ionic and electronic charge carriers, extending throughout the bulk of the organic channel. This attribute renders OECTs fundamentally different from conventional field effect transistors and endows them with unique features, including large gate-to-channel capacitance, low operating voltage, and high transconductance. Owing to the complexity of the mixed ion-electron coupling and transport processes, the OECT device physics is sophisticated and yet to be fully unraveled. Here, we give an account of the one- and two-dimensional drift-diffusion models that have been developed to describe the mixed transport of ions and electrons by finite-element methods and identify key device parameters to be tuned for the next developments in the field.Funding Agencies|Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research [SE13-0045]; Swedish Research CouncilSwedish Research Council [2016-03979]; AForsk [18-313, 19-310]; Olle Engkvists Stiftelse [204-0256]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]</p

Mixed ion-electron transport in organic electrochemical transistors

Organic electrochemical transistors (OECTs) have shown great promise in a variety of applications ranging from digital logic circuits to biosensors and artificial synapses for neuromorphic computing. The working mechanism of OECTs relies on the mixed transport of ionic and electronic charge carriers, extending throughout the bulk of the organic channel. This attribute renders OECTs fundamentally different from conventional field effect transistors and endows them with unique features, including large gate-to-channel capacitance, low operating voltage, and high transconductance. Owing to the complexity of the mixed ion-electron coupling and transport processes, the OECT device physics is sophisticated and yet to be fully unraveled. Here, we give an account of the one- and two-dimensional drift-diffusion models that have been developed to describe the mixed transport of ions and electrons by finite-element methods and identify key device parameters to be tuned for the next developments in the field.Funding Agencies|Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research [SE13-0045]; Swedish Research CouncilSwedish Research Council [2016-03979]; AForsk [18-313, 19-310]; Olle Engkvists Stiftelse [204-0256]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]</p