나노메쉬 유기 전계효과 트랜지스터 제작 및 분석

나노 섬유 기반의 소자, 유기 전계효과 트랜지스터, 생체적합성, 등각 접촉NⅠ. Introduction 1 1.1 Background of Research 1 1.1.1 Technologies for Realizing Soft Electronics 1 1.1.2 Soft Nanomesh Electronics 3 1.2 Organic Field-effect Transistors 6 1.2.1 Device Architecture 6 1.2.2 Organic Semiconductor Materials 7 1.2.3 Working principles and parameters 10 1.2.4 Energy band diagram of organic transistor 14 Ⅱ. Experimental procedure 16 2.1 Fabrication of Nanomesh Organic Field-effect Transistors 16 2.2 Characterization of Nanomesh Organic Field-effect Transistors 18 Ⅲ. Results and discussion 19 3.1 Typical Electrical Performance of Nanomesh Organic Field-effect Transistors 19 3.2 Device Characteristics of Nanomesh Organic Field-effect Transistors 24 3.2.1 DSC Analysis 24 3.2.2 Morphology Studies 25 3.2.3 Water-vapor Permeability Test · 26 3.2.4 Mechanical Robustness 27 3.2.5 Investigation of Cracks Formation in Nanomesh Organic Field-effect Transistor 29 Ⅳ. Conclusion 32MasterdCollectio

An All-Nanofiber-Based Substrate-Less, Extremely Conformal, and Breathable Organic Field Effect Transistor for Biomedical Applications

Nanofiber-based electronic devices have attracted considerable interest owing to their conformal integration on complicated surfaces, flexibility, and sweat permeability. However, building complicated electronics on nanomesh structure has not been successful because of their inferior mechanical properties and processability. This limits their practical application. To achieve system-level device applications, organic field-effect transistors are one of the key components to be integrated with various sensors. Herein, a successful method for fabricating a biocompatible, ultrathin (≈1.5 µm), lightweight (1.85 g m–2), and mechanically durable all-nanofiber-based organic transistor is reported that can be in conformal contact with curved skin. Furthermore, it is the first development with a substrate-less nanomesh organic field effect transistor. The devices exhibit satisfactory electrical performance, including an on/off value of 3.02 × 104 ± 0.9 × 104, saturation mobility of 0.05 ± 0.02 cm2 V− 1 s− 1, subthreshold slope of 1.7 ± 0.2 V dec–1, and threshold voltage of −6 ± 0.5 V. The mechanism of crack initiation is analyzed, via simulation, to understand the deformation of the nanomesh transistors. Furthermore, active matrix integrated tactile sensors entirely on the nanomeshes is successfully demonstrated, indicating their potential applicability in the field of biomedical electronics. © 2022 Wiley-VCH GmbH.FALS

All-Organic, Solution-Processed, Extremely Conformal, Mechanically Biocompatible, and Breathable Epidermal Electrodes

Conformal integration of an epidermal device with the skin, as well as sweat and air permeability, are crucial to reduce stress on biological tissues. Nanofiber-based porous mesh structures (breathable devices) are commonly utilized to prevent skin problems. Noble metals are normally deposited on nanomesh substrates to form breathable electrodes. However, these are expensive and require high-vacuum processes involving time-consuming multistep procedures. Organic materials are suitable alternatives that can be simply processed in solution. We report a simple, cost-effective, mechanically biocompatible, and breathable organic epidermal electrode for biometric devices. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is sprayed on a nanofiber-mesh structure, treated using only heat and water to enhance its biocompatibility and conductivity, and used as the electrode. The treatment is accomplished using an autoclave, simultaneously reducing the electrical resistance and sterilizing the electrode for practical use. This research can lead to affordable and biocompatible epidermal electrodes with improved suitability for various biomedical applications. © 2020 American Chemical Society.FALS

Enhancing the conductivity of PEDOT:PSS films for biomedical applications via hydrothermal treatment

This paper reports a new biocompatible conductivity enhancement of poly (3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) films for biomedical applications. Conductivity of PEDOT:PSS layer was reproducibly from 0.495 to 125.367 S cm(-1) by hydrothermal (HT) treatment. The HT treatment employs water (relative humidity > 80%) and heat (temperature > 61 degrees C) instead of organic solvent doping and post treatments, which can leave undesirable residue. The treatment can be performed using the sterilizing conditions of an autoclave. Additionally, it is possible to simultaneously reduce the electrical resistance, and sterilize the electrode for practical use. The key to conductivity enhancement was the structural rearrangement of PEDOT: PSS, which was determined using atomic force microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy. It was found that PEDOT inter-bridging occurred as a result of the structural rearrangement. Therefore, the conductivity increased on account of the continuous conductive pathways of the PEDOT chains. To test the biocompatible enhancement technique for biomedical applications, certain demonstrations, such as the monitoring of joint movements and skin temperature, and measuring electrocardiogram signals were conducted with the hydrothermal-treated PEDOT:PSS electrode. This simple, biocompatible treatment exhibited significant potential for use in other biomedical applications as well

Multi-deformable piezoelectric energy nano-generator with high conversion efficiency for subtle body movements

Wearable devices for remote medical systems require a reliable power supply to enable full operation during long-term processes. Piezoelectric generators are promising energy sources that use human body movements to generate energy. The wearable device should be able to easily deform with tiny skin deformations to achieve continual energy generation from standard body movements. However, conventional piezoelectric devices cannot deform sufficiently in response to small movements, resulting in an extremely low energy-conversion efficiency when mounted on the human skin. In this study, we report on an ultrathin piezoelectric energy nano-generator (U-PENG) based on poly(vinylidene fluoride-trifluoroethylene). Owing to their thin structure (4 µm), the proposed U-PENGs conformally adhere to soft human skin and generate energy from subtle movements, such as eye blinking and breathing. These novel devices provide energy conversion efficiency of ~18.85%, which is ~971% higher than thicker samples with identical structures. Owing to their ultrathin structure, high efficiency, and excellent skin attachability, U-PENGs can be integrated with biodevices for use as power sources. © 2022FALS