Pub Date : 2023-03-16DOI: 10.1088/2058-8585/acc4d7
Aqsa Javaid, Muhammad Hamza Zulfiqar, Muhammad Shoaib Saleem, Muhammad Atif Khan, Muhammad Zubair, M. Q. Mehmood, Y. Massoud
Emerging technologies that exhibit features of biodegradability and eco-friendliness are potential game changers. Paper is a cost-effective and easily available material that has proved itself a promising candidate for manufacturing strain sensors due to its easy integration into flexible electronics. In this work, an ultra-sensitive and highly stable strain sensor is presented. Easily available materials are used for sensors development and very easy and simple fabrication. The modified interdigital capacitor structure is fabricated on a simple printing paper, whereas copper tape is used as an electrode material. In the anticipated work, the milestones of high sensitivity, durability, and fast response time are achieved. The proposed flexible strain sensor is eco-friendly, bio-degradable, inexpensive, and responds well to applied strain. The proposed work exhibits a fast response time of 0.56 s. The high gauge factor value of 3040.26 and stability up to 5000 cycles. The proposed prototype has been also implemented on the human body for monitoring physical activities and fitness exercises. The proposed strain sensor is an outstandingly good option for assimilation into wearable systems like remote healthcare systems, electromechanical sensing, and human physical monitoring.
{"title":"Paper-based wearable ultra-sensitive strain sensors for fitness monitoring","authors":"Aqsa Javaid, Muhammad Hamza Zulfiqar, Muhammad Shoaib Saleem, Muhammad Atif Khan, Muhammad Zubair, M. Q. Mehmood, Y. Massoud","doi":"10.1088/2058-8585/acc4d7","DOIUrl":"https://doi.org/10.1088/2058-8585/acc4d7","url":null,"abstract":"Emerging technologies that exhibit features of biodegradability and eco-friendliness are potential game changers. Paper is a cost-effective and easily available material that has proved itself a promising candidate for manufacturing strain sensors due to its easy integration into flexible electronics. In this work, an ultra-sensitive and highly stable strain sensor is presented. Easily available materials are used for sensors development and very easy and simple fabrication. The modified interdigital capacitor structure is fabricated on a simple printing paper, whereas copper tape is used as an electrode material. In the anticipated work, the milestones of high sensitivity, durability, and fast response time are achieved. The proposed flexible strain sensor is eco-friendly, bio-degradable, inexpensive, and responds well to applied strain. The proposed work exhibits a fast response time of 0.56 s. The high gauge factor value of 3040.26 and stability up to 5000 cycles. The proposed prototype has been also implemented on the human body for monitoring physical activities and fitness exercises. The proposed strain sensor is an outstandingly good option for assimilation into wearable systems like remote healthcare systems, electromechanical sensing, and human physical monitoring.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44487605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-08DOI: 10.1088/2058-8585/acc25c
Thennarasi Govindan, S. Palaniswamy, M. Kanagasabai, Sachin Kumar, M. Alsath
This paper presents the design and analysis of a multiple-input-multiple-output (MIMO) textile antenna for wireless body area network (WBAN) applications. The MIMO antenna is comprised of four identical modified rhombus-shaped monopole antenna elements of size of 0.57 λ0× 0.57λ0× 0.015λ0 , where λ0 is the wavelength calculated at the lowest operating frequency. The antenna is backed by a 6 ×6 frequency selective surface (FSS) of dimensions of 0.84 λ0× 0.84λ0× 0.015λ0 to improve gain and to reduce specific absorption rate (SAR). The antenna has an impedance bandwidth (S 11 ⩽ −10 dB) of 8.8 GHz (2.8–11.6 GHz) and isolation of >19 dB between the resonating elements. In order to assess the MIMO antenna’s flexibility, the bending analysis is performed for various bending radii. The obtained diversity metrics are: envelope correlation coefficient <0.5 dB, diversity gain <10 dB, channel capacity loss <0.4 bits s−1 Hz−1, and total active reflection coefficient <−10 dB. The performance of the antenna with and without FSS is investigated for gain enhancement and SAR reduction. With the help of FSS, the antenna gain is increased to 8.44 dBi, and the SAR reduced from 6.99 Watt kg−1 to 0.0273 Watt kg−1. The FSS achieves the highest efficiency of 96%. The designed antenna is suitable for smart textile applications due to its low SAR, high gain, and wider impedance bandwidth.
{"title":"Low specific absorption rate quad-port multiple-input-multiple-output limber antenna integrated with flexible frequency selective surface for WBAN applications","authors":"Thennarasi Govindan, S. Palaniswamy, M. Kanagasabai, Sachin Kumar, M. Alsath","doi":"10.1088/2058-8585/acc25c","DOIUrl":"https://doi.org/10.1088/2058-8585/acc25c","url":null,"abstract":"This paper presents the design and analysis of a multiple-input-multiple-output (MIMO) textile antenna for wireless body area network (WBAN) applications. The MIMO antenna is comprised of four identical modified rhombus-shaped monopole antenna elements of size of 0.57 λ0× 0.57λ0× 0.015λ0 , where λ0 is the wavelength calculated at the lowest operating frequency. The antenna is backed by a 6 ×6 frequency selective surface (FSS) of dimensions of 0.84 λ0× 0.84λ0× 0.015λ0 to improve gain and to reduce specific absorption rate (SAR). The antenna has an impedance bandwidth (S 11 ⩽ −10 dB) of 8.8 GHz (2.8–11.6 GHz) and isolation of >19 dB between the resonating elements. In order to assess the MIMO antenna’s flexibility, the bending analysis is performed for various bending radii. The obtained diversity metrics are: envelope correlation coefficient <0.5 dB, diversity gain <10 dB, channel capacity loss <0.4 bits s−1 Hz−1, and total active reflection coefficient <−10 dB. The performance of the antenna with and without FSS is investigated for gain enhancement and SAR reduction. With the help of FSS, the antenna gain is increased to 8.44 dBi, and the SAR reduced from 6.99 Watt kg−1 to 0.0273 Watt kg−1. The FSS achieves the highest efficiency of 96%. The designed antenna is suitable for smart textile applications due to its low SAR, high gain, and wider impedance bandwidth.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41672520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-03DOI: 10.1088/2058-8585/acc114
Joana Figueira, Renato Miguel Bonito, José Tiago Carvalho, E. Vieira, Cristina Gaspar, Joana Loureiro, J. Correia, E. Fortunato, R. Martins, Luís Pereira
Despite the undoubtable interest in energy conversion, thermoelectric (TE) materials can be approached from a temperature-sensitive perspective, as they can detect small thermal stimuli, such as a human touch or contact with cold/hot objects. This feature offers possibilities for different applications one of them being the integration with scalable and cost-effective, biocompatible, flexible, and lightweight thermal sensing solutions, exploring the combination of sustainable Seebeck coefficient-holding materials with printing techniques and flexible substrates. In this work, ethyl cellulose and graphite flakes inks were optimized to be used as functional material for flexible thermal touch sensors produced by screen-printing. Graphite concentrations of 10, 20 and 30 wt% were tested, with 1, 2 and 3 printed layers on four different substrates—office paper, sticker label paper, standard cotton, and organic cotton. The conjugation of these variables was assessed in terms of printability, sheet resistance and TE response. The best electrical-TE output combination is achieved by printing two layers of the ink with 20 wt% of graphite on an office paper substrate. Subsequently, thermal touch sensors with up to 48 TE elements were produced to increase the output voltage response (>4.5 mV) promoted by a gloved finger touch. Fast and repeatable touch recognition were obtained in optimized devices with a signal-to-noise ratio up to 340 and rise times bellow 0.5 s. The results evidence that the screen-printed graphite-based inks are highly suitable for flexible TE sensing applications.
{"title":"Screen-printed, flexible, and eco-friendly thermoelectric touch sensors based on ethyl cellulose and graphite flakes inks","authors":"Joana Figueira, Renato Miguel Bonito, José Tiago Carvalho, E. Vieira, Cristina Gaspar, Joana Loureiro, J. Correia, E. Fortunato, R. Martins, Luís Pereira","doi":"10.1088/2058-8585/acc114","DOIUrl":"https://doi.org/10.1088/2058-8585/acc114","url":null,"abstract":"Despite the undoubtable interest in energy conversion, thermoelectric (TE) materials can be approached from a temperature-sensitive perspective, as they can detect small thermal stimuli, such as a human touch or contact with cold/hot objects. This feature offers possibilities for different applications one of them being the integration with scalable and cost-effective, biocompatible, flexible, and lightweight thermal sensing solutions, exploring the combination of sustainable Seebeck coefficient-holding materials with printing techniques and flexible substrates. In this work, ethyl cellulose and graphite flakes inks were optimized to be used as functional material for flexible thermal touch sensors produced by screen-printing. Graphite concentrations of 10, 20 and 30 wt% were tested, with 1, 2 and 3 printed layers on four different substrates—office paper, sticker label paper, standard cotton, and organic cotton. The conjugation of these variables was assessed in terms of printability, sheet resistance and TE response. The best electrical-TE output combination is achieved by printing two layers of the ink with 20 wt% of graphite on an office paper substrate. Subsequently, thermal touch sensors with up to 48 TE elements were produced to increase the output voltage response (>4.5 mV) promoted by a gloved finger touch. Fast and repeatable touch recognition were obtained in optimized devices with a signal-to-noise ratio up to 340 and rise times bellow 0.5 s. The results evidence that the screen-printed graphite-based inks are highly suitable for flexible TE sensing applications.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47158707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-02DOI: 10.1088/2058-8585/acc07f
A. Roy, Catherine Beaumont, Mario Leclerc, Konrad Walus
Polythiophenes comprise a class of emerging materials with potential applications in the field of temperature sensing. In this article, we validate and apply an integrated blending and printing methodology to combinatorially study libraries of pristine and compositionally graded blends of polythiophenes PEDOT:PSS and P(S-EDOT) (a PEDOT-like self-doped conjugated polymer) to understand their intrinsic electrical conductivity behaviour and along with its temperature dependence on blend composition and ambient temperature. Hypothesis testing is conducted to identify optima in electrical conductivity from combinations of input material proportions intended to meet multiple requirements otherwise difficult to achieve in any single-component solution-processable material. We chose PEDOT:PSS as a commercial developed intrinsically conductive polythiophene and with it, compared a novel self-doped polythiophene P(S-EDOT) as its potential replacement or complement as a sensor material. The electrical and morphological characteristics for both polymers and their blends were investigated for use as different components of temperature sensing applications. Different error sources within the process flow were considered for statistically significant conclusions regarding the utility of different compositions for different aspects of temperature sensing.
{"title":"Evaluating polythiophenes as temperature sensing materials using combinatorial inkjet printing","authors":"A. Roy, Catherine Beaumont, Mario Leclerc, Konrad Walus","doi":"10.1088/2058-8585/acc07f","DOIUrl":"https://doi.org/10.1088/2058-8585/acc07f","url":null,"abstract":"Polythiophenes comprise a class of emerging materials with potential applications in the field of temperature sensing. In this article, we validate and apply an integrated blending and printing methodology to combinatorially study libraries of pristine and compositionally graded blends of polythiophenes PEDOT:PSS and P(S-EDOT) (a PEDOT-like self-doped conjugated polymer) to understand their intrinsic electrical conductivity behaviour and along with its temperature dependence on blend composition and ambient temperature. Hypothesis testing is conducted to identify optima in electrical conductivity from combinations of input material proportions intended to meet multiple requirements otherwise difficult to achieve in any single-component solution-processable material. We chose PEDOT:PSS as a commercial developed intrinsically conductive polythiophene and with it, compared a novel self-doped polythiophene P(S-EDOT) as its potential replacement or complement as a sensor material. The electrical and morphological characteristics for both polymers and their blends were investigated for use as different components of temperature sensing applications. Different error sources within the process flow were considered for statistically significant conclusions regarding the utility of different compositions for different aspects of temperature sensing.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41728536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-27DOI: 10.1088/2058-8585/acbf65
Fei Liu, A. Sneck, A. Alastalo, J. Leppäniemi
Besides the metal oxide thin film transistors (TFTs) in flat-panel displays that are fabricated using vacuum-processes, there is a growing interest in the fabrication of metal oxide TFTs by means of scalable, low-cost solution and printing processes for applications such as flexible displays and biosensors. Although devices with printed semiconductor and gate insulator can exhibit good electrical performance, source/drain-contacts (S/D) printed from silver (Ag) nanoparticles (NPs) typically suffer from deteriorated electrical characteristics and stability problems. On the other hand, metals providing good contacts, such as aluminum (Al), titanium (Ti) and molybdenum (Mo), cannot be formed as air-stable NPs. To overcome these issues, we have developed a patterning method based on high-resolution reverse-offset printing (ROP) of a sacrificial polymer resist layer. ROP delivers patterns with micrometer-level resolution and steep sidewalls, which are ideal for patterning vacuum-deposited metal contacts at high resolution via lift-off process. Solution-processed indium oxide (In2O3) TFTs were successfully fabricated by using ROP lift-off process for patterning of gate and S/D-electrodes using Al. The fabricated In2O3-based TFTs with Al S/D-contacts exhibit good uniformity, constant mobility (μ sat) ∼ 2 cm2 (V s)−1 over a wide range of width/length-ratios (W/L) and almost zero turn-on voltage (V on) ∼ −0.2 V. TFTs down to 5 µm channel lengths were successfully patterned. Further development of the fabrication process could lead to flexible fully-print-patterned high-resolution TFT backplanes for flexible displays, biosensors, photosensors and x-ray detectors.
{"title":"Oxide TFTs with S/D-contacts patterned by high-resolution reverse-offset printed resist layers","authors":"Fei Liu, A. Sneck, A. Alastalo, J. Leppäniemi","doi":"10.1088/2058-8585/acbf65","DOIUrl":"https://doi.org/10.1088/2058-8585/acbf65","url":null,"abstract":"Besides the metal oxide thin film transistors (TFTs) in flat-panel displays that are fabricated using vacuum-processes, there is a growing interest in the fabrication of metal oxide TFTs by means of scalable, low-cost solution and printing processes for applications such as flexible displays and biosensors. Although devices with printed semiconductor and gate insulator can exhibit good electrical performance, source/drain-contacts (S/D) printed from silver (Ag) nanoparticles (NPs) typically suffer from deteriorated electrical characteristics and stability problems. On the other hand, metals providing good contacts, such as aluminum (Al), titanium (Ti) and molybdenum (Mo), cannot be formed as air-stable NPs. To overcome these issues, we have developed a patterning method based on high-resolution reverse-offset printing (ROP) of a sacrificial polymer resist layer. ROP delivers patterns with micrometer-level resolution and steep sidewalls, which are ideal for patterning vacuum-deposited metal contacts at high resolution via lift-off process. Solution-processed indium oxide (In2O3) TFTs were successfully fabricated by using ROP lift-off process for patterning of gate and S/D-electrodes using Al. The fabricated In2O3-based TFTs with Al S/D-contacts exhibit good uniformity, constant mobility (μ sat) ∼ 2 cm2 (V s)−1 over a wide range of width/length-ratios (W/L) and almost zero turn-on voltage (V on) ∼ −0.2 V. TFTs down to 5 µm channel lengths were successfully patterned. Further development of the fabrication process could lead to flexible fully-print-patterned high-resolution TFT backplanes for flexible displays, biosensors, photosensors and x-ray detectors.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43834467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-14DOI: 10.1088/2058-8585/acbbdc
G. Volpes, Simone Valenti, Hima Zafar, Riccardo Pernice, Goran M. Stojanović
In recent years, the importance of flexible and textile electronics in the field of wearable devices has continuously increased, as they are expected to replace conventional wires that exhibit limited resistance to the mechanical stress occurring in on-body applications. Wearable health devices (WHDs) can provide physiological information about various body parts and employ distributed sensor networks. Among the sensors typically integrated within WHDs, those based on the I2C communication protocol are very common and exploit signals transmitted at frequencies up to hundreds of kilohertz. Therefore, robust communication is required to guarantee a proper transmission of the signal at those frequencies. In this context, we have realized embroidered conductive threads exhibiting a lower resistance, appositely designed to replace conventional wires in a microcontroller-based wearable device employing I2C sensors. A commercial conductive thread (silver coated polyamide) was used to embroider the conductive lines on to cotton fabric. Preliminary measurements were performed to characterize the response of these materials to signals typically operated within the I2C communication protocol at different path lengths. Resistive measurements have also been performed to stimulate different environmental conditions, that is, temperature, the effect of sweating, and repeated washing cycles, also apply mechanical stress, i.e. twisting, with promising results that validate our conductive paths for digital signal communication.
{"title":"Feasibility of conductive embroidered threads for I2C sensors in microcontroller-based wearable electronics","authors":"G. Volpes, Simone Valenti, Hima Zafar, Riccardo Pernice, Goran M. Stojanović","doi":"10.1088/2058-8585/acbbdc","DOIUrl":"https://doi.org/10.1088/2058-8585/acbbdc","url":null,"abstract":"In recent years, the importance of flexible and textile electronics in the field of wearable devices has continuously increased, as they are expected to replace conventional wires that exhibit limited resistance to the mechanical stress occurring in on-body applications. Wearable health devices (WHDs) can provide physiological information about various body parts and employ distributed sensor networks. Among the sensors typically integrated within WHDs, those based on the I2C communication protocol are very common and exploit signals transmitted at frequencies up to hundreds of kilohertz. Therefore, robust communication is required to guarantee a proper transmission of the signal at those frequencies. In this context, we have realized embroidered conductive threads exhibiting a lower resistance, appositely designed to replace conventional wires in a microcontroller-based wearable device employing I2C sensors. A commercial conductive thread (silver coated polyamide) was used to embroider the conductive lines on to cotton fabric. Preliminary measurements were performed to characterize the response of these materials to signals typically operated within the I2C communication protocol at different path lengths. Resistive measurements have also been performed to stimulate different environmental conditions, that is, temperature, the effect of sweating, and repeated washing cycles, also apply mechanical stress, i.e. twisting, with promising results that validate our conductive paths for digital signal communication.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43965974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-14DOI: 10.1088/2058-8585/acbbdd
Chun Liu, Lei Zhou, Zhao-Hua Zhou, Fei-Fan Li, Xiao-Qin Wei, Miao Xu, L. Wang, Weijing Wu, Junbiao Peng
Foldable displays have become increasingly used as a solution to the portability-practicality trade-off. A new scan driver integrated with metal oxide thin film transistors (MO TFTs) is proposed for foldable displays to overcome the effects of threshold voltage shifts on the scan driver output. In the scan driver, a feedback section and two series to transistor structures are used to keep the voltage of the key node to sustain a normal output, with this structure, the lower the voltage of the negative supply, the more stable the scan driver will be. Some flexible MO TFTs and 60 stage scan drivers are fabricated by etch stop layer structures on the polyimide substrate. Under different strains and 100 000 times bending with the minimum 3.5 mm bending radius, the characteristics of MO TFTs and the output waveform of the scan driver are measured. Experimental results show that the proposed scan driver shows high reliability since only a little voltage fluctuation occurs at the outputs after the bending test and has a better output waveform with a lower voltage of the negative supply.
{"title":"A high-reliability scan driver integrated circuit by MO TFTs for a foldable display","authors":"Chun Liu, Lei Zhou, Zhao-Hua Zhou, Fei-Fan Li, Xiao-Qin Wei, Miao Xu, L. Wang, Weijing Wu, Junbiao Peng","doi":"10.1088/2058-8585/acbbdd","DOIUrl":"https://doi.org/10.1088/2058-8585/acbbdd","url":null,"abstract":"Foldable displays have become increasingly used as a solution to the portability-practicality trade-off. A new scan driver integrated with metal oxide thin film transistors (MO TFTs) is proposed for foldable displays to overcome the effects of threshold voltage shifts on the scan driver output. In the scan driver, a feedback section and two series to transistor structures are used to keep the voltage of the key node to sustain a normal output, with this structure, the lower the voltage of the negative supply, the more stable the scan driver will be. Some flexible MO TFTs and 60 stage scan drivers are fabricated by etch stop layer structures on the polyimide substrate. Under different strains and 100 000 times bending with the minimum 3.5 mm bending radius, the characteristics of MO TFTs and the output waveform of the scan driver are measured. Experimental results show that the proposed scan driver shows high reliability since only a little voltage fluctuation occurs at the outputs after the bending test and has a better output waveform with a lower voltage of the negative supply.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46923118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-10DOI: 10.1088/2058-8585/acbb17
Li Wang, Yang Geng
A conductive layer deposited on a rough surface can effectively improve the performance of a pressure sensor; however, its further application requires patterning of the conductive layer to obtain the corresponding electrical layout. In this paper, a facile patterning method with few steps was proposed for patterning silver nanowires on sandpaper. This method employed a photocurable resin as the key material to define the pattern using a photomask under UV exposure. It was found that greater cure depths and narrower light-transmitting areas require longer exposure times. A pattern with linewidth of approximately 40 μm was obtained on M-400 sandpaper (M-400 stands for the mesh number). Based on this method, pressure sensors consisting of interdigital electrodes with rough surfaces and sponge-sensing layers were fabricated. The best resulting sensor exhibited a high-pressure sensitivity of 21.89 kPa−11 for less than 2 kPa, a low detection limit (24.5 Pa), low operating voltage (0.01 V), and short response time (84 ms). Moreover, this patterning method has no special requirements for materials and substrates and thus can be applied to pattern other materials on rough or smooth surface substrates.
{"title":"A facile method to pattern silver nanowires on sandpaper and its application in pressure sensors","authors":"Li Wang, Yang Geng","doi":"10.1088/2058-8585/acbb17","DOIUrl":"https://doi.org/10.1088/2058-8585/acbb17","url":null,"abstract":"A conductive layer deposited on a rough surface can effectively improve the performance of a pressure sensor; however, its further application requires patterning of the conductive layer to obtain the corresponding electrical layout. In this paper, a facile patterning method with few steps was proposed for patterning silver nanowires on sandpaper. This method employed a photocurable resin as the key material to define the pattern using a photomask under UV exposure. It was found that greater cure depths and narrower light-transmitting areas require longer exposure times. A pattern with linewidth of approximately 40 μm was obtained on M-400 sandpaper (M-400 stands for the mesh number). Based on this method, pressure sensors consisting of interdigital electrodes with rough surfaces and sponge-sensing layers were fabricated. The best resulting sensor exhibited a high-pressure sensitivity of 21.89 kPa−11 for less than 2 kPa, a low detection limit (24.5 Pa), low operating voltage (0.01 V), and short response time (84 ms). Moreover, this patterning method has no special requirements for materials and substrates and thus can be applied to pattern other materials on rough or smooth surface substrates.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41812643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-10DOI: 10.1088/2058-8585/acbb18
Yongqing Zhang, Yizhou Jiang, Feng Ge, Yunbo Li
A safe and high-performance electrothermal heater needs a lower operating voltage to produce heat for a long time and with high efficiency. The graphene-carbon nanotubes composite films and the AgNWs (siliver nanowires) dispersions were prepared and the AgNWs were successfully coated on to the composite films. The electrothermal performance of composite films with different carbon nanotubes (CNTs) contents, polymer additions and coating AgNWs were investigated. The maximum heating temperature decreases when the content of the polymer increases. In addition, the maximum temperature increases with the addition of CNTs. The sheet resistance gradually decreases with improving AgNWs coated amount and the sheet resistance changes little with the bending times on the whole. The microstructure of composite films coated with AgNWs revealed that AgNWs filled the holes on the surface of the composite films. Besides, the electrothermal efficiency, heating rate and cooling rate were significantly improved. For the electrothermal performance of the composite film coated with AgNWs only on the contact surface, the electrothermal efficiency, heating rate and cooling rate were also significantly improved compared with those of the composite films without an AgNWs coating. Therefore, composite film coating with AgNWs is one effective method to significantly improve the electrothermal performance for Gr composite film.
{"title":"Improved electrothermal performance of graphene-carbon nanotubes composite films utilizing AgNWs coating method","authors":"Yongqing Zhang, Yizhou Jiang, Feng Ge, Yunbo Li","doi":"10.1088/2058-8585/acbb18","DOIUrl":"https://doi.org/10.1088/2058-8585/acbb18","url":null,"abstract":"A safe and high-performance electrothermal heater needs a lower operating voltage to produce heat for a long time and with high efficiency. The graphene-carbon nanotubes composite films and the AgNWs (siliver nanowires) dispersions were prepared and the AgNWs were successfully coated on to the composite films. The electrothermal performance of composite films with different carbon nanotubes (CNTs) contents, polymer additions and coating AgNWs were investigated. The maximum heating temperature decreases when the content of the polymer increases. In addition, the maximum temperature increases with the addition of CNTs. The sheet resistance gradually decreases with improving AgNWs coated amount and the sheet resistance changes little with the bending times on the whole. The microstructure of composite films coated with AgNWs revealed that AgNWs filled the holes on the surface of the composite films. Besides, the electrothermal efficiency, heating rate and cooling rate were significantly improved. For the electrothermal performance of the composite film coated with AgNWs only on the contact surface, the electrothermal efficiency, heating rate and cooling rate were also significantly improved compared with those of the composite films without an AgNWs coating. Therefore, composite film coating with AgNWs is one effective method to significantly improve the electrothermal performance for Gr composite film.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43449756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-09DOI: 10.1088/2058-8585/acbaab
Qiushi Li, Euichul Chung, Antonia Antoniou, Olivier N Pierron
The electrical performance of stretchable electronic inks degrades as they undergo cyclic deformation during use, posing a major challenge to their reliability. The experimental characterization of ink fatigue behavior can be a time-consuming process, and models allowing accurate resistance evolution and life estimates are needed. Here, a model is proposed for determining the electrical resistance evolution during cyclic loading of a screen-printed composite conductive ink. The model relies on two input specimen-characteristic curves, assumes a constant rate of normalized resistance increase for a given strain amplitude, and incorporates the effects of both mean strain and strain amplitude. The model predicts the normalized resistance evolution of a cyclic test with reasonable accuracy. The mean strain effects are secondary compared to strain amplitude, except for large strain amplitudes (>10%) and mean strains (>30%). A trace width effect is found for the fatigue behavior of 1 mm vs 2 mm wide specimens. The input specimen-characteristic curves are trace-width dependent, and the model predicts a decrease in N f by a factor of up to 2 for the narrower trace width, in agreement with the experimental results. Two different methods are investigated to generate the rate of normalized resistance increase curves: uninterrupted fatigue tests (requiring ∼6–7 cyclic tests), and a single interrupted cyclic test (requiring only one specimen tested at progressively higher strain amplitude values). The results suggest that the initial decrease in normalized resistance rate only occurs for specimens with no prior loading. The minimum-rate curve is therefore recommended for more accurate fatigue estimates.
{"title":"Modeling resistance increase in a composite ink under cyclic loading","authors":"Qiushi Li, Euichul Chung, Antonia Antoniou, Olivier N Pierron","doi":"10.1088/2058-8585/acbaab","DOIUrl":"https://doi.org/10.1088/2058-8585/acbaab","url":null,"abstract":"The electrical performance of stretchable electronic inks degrades as they undergo cyclic deformation during use, posing a major challenge to their reliability. The experimental characterization of ink fatigue behavior can be a time-consuming process, and models allowing accurate resistance evolution and life estimates are needed. Here, a model is proposed for determining the electrical resistance evolution during cyclic loading of a screen-printed composite conductive ink. The model relies on two input specimen-characteristic curves, assumes a constant rate of normalized resistance increase for a given strain amplitude, and incorporates the effects of both mean strain and strain amplitude. The model predicts the normalized resistance evolution of a cyclic test with reasonable accuracy. The mean strain effects are secondary compared to strain amplitude, except for large strain amplitudes (>10%) and mean strains (>30%). A trace width effect is found for the fatigue behavior of 1 mm vs 2 mm wide specimens. The input specimen-characteristic curves are trace-width dependent, and the model predicts a decrease in N f by a factor of up to 2 for the narrower trace width, in agreement with the experimental results. Two different methods are investigated to generate the rate of normalized resistance increase curves: uninterrupted fatigue tests (requiring ∼6–7 cyclic tests), and a single interrupted cyclic test (requiring only one specimen tested at progressively higher strain amplitude values). The results suggest that the initial decrease in normalized resistance rate only occurs for specimens with no prior loading. The minimum-rate curve is therefore recommended for more accurate fatigue estimates.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42456873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：