Pub Date : 2023-08-09DOI: 10.1088/2058-8585/acee93
Yan Wang, Yingjie Tang, Yitong Chen, Dingwei Li, Huihui Ren, Guolei Liu, Fanfan Li, Ran Jin, Bowen Zhu
Amorphous oxide semiconductors, especially indium gallium zinc oxide (IGZO), have been widely studied and obtained significant progress in flexible thin-film transistors (TFTs) due to the high carrier mobility and low deposition temperature. However, a further annealing step is generally required to activate electrical properties and improve the device performance, which limited their applications in flexible electronics. In this study, we achieved flexible TFTs and arrays using co-sputtered IGZO and indium tin oxide (ITO) as channels deposited at room temperature without post-annealing. It was found that better transistor switching properties could be effectively achieved by regulating the sputtering power of ITO in the co-sputtered deposition. The device performance is comparable to that of the conventional oxide TFTs with high annealing temperatures (⩾300 °C), exhibiting a high saturation mobility (μ sat) of 15.3 cm2 V−1s−1, a small subthreshold swing (SS) of 0.21 V dec−1, and a very high on–off ratio (I on/off) of 1011. In addition, a 12 × 12 flexible TFT array was achieved with uniform performance owing to the low-temperature processing advantage of this technique. The flexible TFTs exhibited robust mechanical flexibility with a minimum bending radius of 5 mm and bending cycles up to 1000. Furthermore, an inverter based on co-sputtered IGZO and ITO was demonstrated with the maximum gain of 22. All these achievements based on the proposed TFTs without post-annealing process are expected to promote the applications in advanced flexible displays and large-area integrated circuits.
非晶氧化物半导体，特别是铟镓锌氧化物（IGZO），由于其高载流子迁移率和低沉积温度，在柔性薄膜晶体管（TFT）中得到了广泛的研究并取得了重大进展。然而，通常需要进一步的退火步骤来激活电性能并提高器件性能，这限制了它们在柔性电子器件中的应用。在这项研究中，我们使用共溅射IGZO和氧化铟锡（ITO）作为通道在室温下沉积而无需后退火，实现了柔性TFT和阵列。研究发现，在共溅射沉积中，通过调节ITO的溅射功率可以有效地获得更好的晶体管开关性能。该器件性能与具有高退火温度（⩾300°C）的传统氧化物TFT相当，表现出15.3 cm2 V−1s−1的高饱和迁移率（μsat）、0.21 V dec−1的小亚阈值摆动（SS）和1011的非常高的导通/关断比（I on/off）。此外，由于该技术的低温加工优势，实现了性能均匀的12×12柔性TFT阵列。柔性TFT表现出强大的机械柔性，最小弯曲半径为5mm，弯曲周期高达1000。此外，基于共溅射IGZO和ITO的逆变器被证明具有22的最大增益。基于所提出的无后退火工艺的TFT的所有这些成果有望促进其在先进柔性显示器和大面积集成电路中的应用。
{"title":"Room-temperature fabrication of flexible oxide TFTs by co-sputtering of IGZO and ITO","authors":"Yan Wang, Yingjie Tang, Yitong Chen, Dingwei Li, Huihui Ren, Guolei Liu, Fanfan Li, Ran Jin, Bowen Zhu","doi":"10.1088/2058-8585/acee93","DOIUrl":"https://doi.org/10.1088/2058-8585/acee93","url":null,"abstract":"Amorphous oxide semiconductors, especially indium gallium zinc oxide (IGZO), have been widely studied and obtained significant progress in flexible thin-film transistors (TFTs) due to the high carrier mobility and low deposition temperature. However, a further annealing step is generally required to activate electrical properties and improve the device performance, which limited their applications in flexible electronics. In this study, we achieved flexible TFTs and arrays using co-sputtered IGZO and indium tin oxide (ITO) as channels deposited at room temperature without post-annealing. It was found that better transistor switching properties could be effectively achieved by regulating the sputtering power of ITO in the co-sputtered deposition. The device performance is comparable to that of the conventional oxide TFTs with high annealing temperatures (⩾300 °C), exhibiting a high saturation mobility (μ sat) of 15.3 cm2 V−1s−1, a small subthreshold swing (SS) of 0.21 V dec−1, and a very high on–off ratio (I on/off) of 1011. In addition, a 12 × 12 flexible TFT array was achieved with uniform performance owing to the low-temperature processing advantage of this technique. The flexible TFTs exhibited robust mechanical flexibility with a minimum bending radius of 5 mm and bending cycles up to 1000. Furthermore, an inverter based on co-sputtered IGZO and ITO was demonstrated with the maximum gain of 22. All these achievements based on the proposed TFTs without post-annealing process are expected to promote the applications in advanced flexible displays and large-area integrated circuits.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45139899","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 : 2023-08-07DOI: 10.1088/2058-8585/acedbe
X. Wu, K. Yin, M. Yang, Yufeng Hu, Hongshang Peng
All-inorganic perovskite quantum dots (PQDs) have received considerable attentions due to their fascinating optical properties. However, the mainstream preparation methods rely on toxic solvents, raising significant environmental and safety concerns. In this work, ethyl acetate was chosen as the environmentally friendly anti-solvent to prepare silica-coated CsPbBr3 PQDs using a aminoalkoxysilane-assisted reprecipitation–encapsulation method. The as-prepared PQDs exhibited tunable emission wavelength and a medium photoluminescence quantum yield (PLQY) of 60%. Furthermore, CsPbBr3 PQDs were post-treated by different ligands with the aim of passivating surface defects. This strategy successfully mitigated the presence of surface defects and minimized non-radiative recombination losses in PQDs. As a result, the PLQY (achieving up to 73%) and stability of PQDs were substantially enhanced (luminescence stability improved by about 40% under the same test conditions). Our studies offer a novel approach for the environmentally friendly large-scale production of PQDs, opening up new possibilities for their practical applications.
{"title":"Green synthesis of highly luminescent CsPbBr3 quantum dots through silica coating and post-treatment with ligands","authors":"X. Wu, K. Yin, M. Yang, Yufeng Hu, Hongshang Peng","doi":"10.1088/2058-8585/acedbe","DOIUrl":"https://doi.org/10.1088/2058-8585/acedbe","url":null,"abstract":"All-inorganic perovskite quantum dots (PQDs) have received considerable attentions due to their fascinating optical properties. However, the mainstream preparation methods rely on toxic solvents, raising significant environmental and safety concerns. In this work, ethyl acetate was chosen as the environmentally friendly anti-solvent to prepare silica-coated CsPbBr3 PQDs using a aminoalkoxysilane-assisted reprecipitation–encapsulation method. The as-prepared PQDs exhibited tunable emission wavelength and a medium photoluminescence quantum yield (PLQY) of 60%. Furthermore, CsPbBr3 PQDs were post-treated by different ligands with the aim of passivating surface defects. This strategy successfully mitigated the presence of surface defects and minimized non-radiative recombination losses in PQDs. As a result, the PLQY (achieving up to 73%) and stability of PQDs were substantially enhanced (luminescence stability improved by about 40% under the same test conditions). Our studies offer a novel approach for the environmentally friendly large-scale production of PQDs, opening up new possibilities for their practical applications.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44085035","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 : 2023-08-07DOI: 10.1088/2058-8585/acedbf
H. Le, Aamir Minhas-Khan, S. Nambi, Gerd Grau, Wen Shen, Dazhong Wu
While laser-induced graphitic carbon (LIGC) has been used to fabricate cost-effective conductive carbon on flexible substrates for applications such as sensors and energy storage devices, predicting the resistance of the component fabricated via LIGC remains challenging. In this study, a two-step machine learning-based modeling framework is developed to predict the sheet resistance of the materials fabricated using LIGC. The two-step modeling framework consists of classification and regression. First, random forest (RF) is used to classify successful and failed trials. Second, extreme gradient boosting (XGBoost), RF, support vector machine with radial basis function, multivariate adaptive spline regression, and multilayer perceptron are used to predict the sheet resistance in each successful trial. In addition, an analysis of the change in sheet resistance with respect to laser energy per unit area is conducted to remove data points with high sheet resistance. XGBoost is also used to determine the importance of each process parameter. We demonstrate the modeling framework on datasets collected from experiments where LIGC lines (1D) and LIGC squares (2D) are engraved. For the 1D dataset, the RF classification model achieves a 95% accuracy. For both 1D and 2D datasets, a comparative study shows that XGBoost outperforms other algorithms. XGBoost predicts the sheet resistance of the LIGC lines and squares with a MAPE of 7.08% and 8.75%, respectively. XGBoost also identifies laser resolution as the most significant parameter. Moreover, experimental results show that models built on the dataset merging the 1D and 2D datasets result in lower prediction accuracy than those built on the 1D and 2D datasets separately. The modeling framework allows one to determine the sheet resistance of LIGC with varying laser processing conditions without conducting expensive and time-consuming experiments.
{"title":"Predicting the sheet resistance of laser-induced graphitic carbon using machine learning","authors":"H. Le, Aamir Minhas-Khan, S. Nambi, Gerd Grau, Wen Shen, Dazhong Wu","doi":"10.1088/2058-8585/acedbf","DOIUrl":"https://doi.org/10.1088/2058-8585/acedbf","url":null,"abstract":"While laser-induced graphitic carbon (LIGC) has been used to fabricate cost-effective conductive carbon on flexible substrates for applications such as sensors and energy storage devices, predicting the resistance of the component fabricated via LIGC remains challenging. In this study, a two-step machine learning-based modeling framework is developed to predict the sheet resistance of the materials fabricated using LIGC. The two-step modeling framework consists of classification and regression. First, random forest (RF) is used to classify successful and failed trials. Second, extreme gradient boosting (XGBoost), RF, support vector machine with radial basis function, multivariate adaptive spline regression, and multilayer perceptron are used to predict the sheet resistance in each successful trial. In addition, an analysis of the change in sheet resistance with respect to laser energy per unit area is conducted to remove data points with high sheet resistance. XGBoost is also used to determine the importance of each process parameter. We demonstrate the modeling framework on datasets collected from experiments where LIGC lines (1D) and LIGC squares (2D) are engraved. For the 1D dataset, the RF classification model achieves a 95% accuracy. For both 1D and 2D datasets, a comparative study shows that XGBoost outperforms other algorithms. XGBoost predicts the sheet resistance of the LIGC lines and squares with a MAPE of 7.08% and 8.75%, respectively. XGBoost also identifies laser resolution as the most significant parameter. Moreover, experimental results show that models built on the dataset merging the 1D and 2D datasets result in lower prediction accuracy than those built on the 1D and 2D datasets separately. The modeling framework allows one to determine the sheet resistance of LIGC with varying laser processing conditions without conducting expensive and time-consuming experiments.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44631330","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 : 2023-08-03DOI: 10.1088/2058-8585/aced15
Subham Das, M. Bhattacharjee, K. Thiyagarajan, S. Kodagoda
Humans can perceive surface properties of an unfamiliar object without relying solely on vision. One way to achieve it is by physically touching the object. This human-inspired tactile perception is a complementary skill for robotic tactile perception. Robot perception depends on the informational quality of the tactile sensor; thus, packaging sensors and integrating them with robots plays a crucial role. In this work, we investigate the influence of conformable packaging designs on soft polydimethylsiloxane-based flexible pressure sensors that work in a variety of surface conditions and load levels. Four different 3D printed packaging designs capable of maintaining sensor trends have been developed. The low detection limits of 0.7 kPa and 0.1 kPa in the piezoresistive and piezocapacitive sensors, respectively, remain unaffected, and a performance variation as low as 30% is observed. Coefficient of variation and sensitivity studies have also been performed. Limit tests show that the designs can handle large forces ranging from 500 N to more than a 1000 N. Lastly, a qualitative study was performed, which covered prospective use-case scenarios as well as the advantages and downsides of each sensor casing design. Overall, the findings indicate that each sensor casing is distinct and best suited for tactile perception when interacting with objects, depending on surface properties.
{"title":"Conformable packaging of a soft pressure sensor for tactile perception","authors":"Subham Das, M. Bhattacharjee, K. Thiyagarajan, S. Kodagoda","doi":"10.1088/2058-8585/aced15","DOIUrl":"https://doi.org/10.1088/2058-8585/aced15","url":null,"abstract":"Humans can perceive surface properties of an unfamiliar object without relying solely on vision. One way to achieve it is by physically touching the object. This human-inspired tactile perception is a complementary skill for robotic tactile perception. Robot perception depends on the informational quality of the tactile sensor; thus, packaging sensors and integrating them with robots plays a crucial role. In this work, we investigate the influence of conformable packaging designs on soft polydimethylsiloxane-based flexible pressure sensors that work in a variety of surface conditions and load levels. Four different 3D printed packaging designs capable of maintaining sensor trends have been developed. The low detection limits of 0.7 kPa and 0.1 kPa in the piezoresistive and piezocapacitive sensors, respectively, remain unaffected, and a performance variation as low as 30% is observed. Coefficient of variation and sensitivity studies have also been performed. Limit tests show that the designs can handle large forces ranging from 500 N to more than a 1000 N. Lastly, a qualitative study was performed, which covered prospective use-case scenarios as well as the advantages and downsides of each sensor casing design. Overall, the findings indicate that each sensor casing is distinct and best suited for tactile perception when interacting with objects, depending on surface properties.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44826555","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 : 2023-07-31DOI: 10.1088/2058-8585/acebff
Chenyu Zhang, Jiaqi Guo, Shilin Lian, Zongtao Chi, Zhongsen Sun, Yu-Yi Zheng, B. Sun, Tian Liu
Flexible transparent antennas have broad potential applications in wireless communication and RF energy harvesting, providing visualization, small size, and integration functions for electronic devices. The use of optically transparent materials is an essential direction in the development of flexible transparent antennas. In this paper, a flexible and transparent antenna is designed by indium tin oxide material and photolithography process, which is suitable for wideband communication field. The broadband characteristics of the antenna are realized by using irregular slots and rectangular microstrip lines on the ground plane. The antenna operates in the frequency range of 1.73–20 GHz with a relative bandwidth of 168%, which is suitable for ultra-wideband (UWB) applications. The antenna has a compact structure and the relative size of 0.33 λ 0 × 0.28 λ 0. The measured results of the antenna are in good agreement with the simulated results, and the bending and folding tests show that the antenna has good mechanical flexibility and can cover the surface of irregular objects. This pliers-shaped antenna is applicable to a variety of UWB and wireless applications, such as LTE, Wi Max, 5G network, IoT, WIFI, mobile phone keys, and mobile payment.
{"title":"A flexible and transparent pliers shaped antenna for ultra-wideband applications","authors":"Chenyu Zhang, Jiaqi Guo, Shilin Lian, Zongtao Chi, Zhongsen Sun, Yu-Yi Zheng, B. Sun, Tian Liu","doi":"10.1088/2058-8585/acebff","DOIUrl":"https://doi.org/10.1088/2058-8585/acebff","url":null,"abstract":"Flexible transparent antennas have broad potential applications in wireless communication and RF energy harvesting, providing visualization, small size, and integration functions for electronic devices. The use of optically transparent materials is an essential direction in the development of flexible transparent antennas. In this paper, a flexible and transparent antenna is designed by indium tin oxide material and photolithography process, which is suitable for wideband communication field. The broadband characteristics of the antenna are realized by using irregular slots and rectangular microstrip lines on the ground plane. The antenna operates in the frequency range of 1.73–20 GHz with a relative bandwidth of 168%, which is suitable for ultra-wideband (UWB) applications. The antenna has a compact structure and the relative size of 0.33 λ 0 × 0.28 λ 0. The measured results of the antenna are in good agreement with the simulated results, and the bending and folding tests show that the antenna has good mechanical flexibility and can cover the surface of irregular objects. This pliers-shaped antenna is applicable to a variety of UWB and wireless applications, such as LTE, Wi Max, 5G network, IoT, WIFI, mobile phone keys, and mobile payment.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49448521","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 : 2023-07-19DOI: 10.1088/2058-8585/ace8a6
Meltem Tekçin, Damla Rabia Tuzer Hamzaoglu, S. Kursun
In order to meet the increasing food demand, sensors that measure the ambient temperature and humidity in greenhouses are needed for more efficient vegetable and fruit production. For this purpose, two different flexible and resistant textile-based humidity sensors that can measure the humidity at higher levels (80%, 90%, and 100% relative humidity (RH)) were designed and printed directly on the four different greenhouse fabrics using silver and carbon conductive inks. Depending on the humidity value in the environment, the sensor performance was tested based on sensor electrical resistance measurements with respect to repeated bending/cyclic tests, rubbing, ultraviolet (UV) exposure/ weatherability (against UV and raining) tests in order to simulate greenhouse conditions for smart agriculture. Despite applying 1024 bending cycles, up to 20 rubbing cycles, and 10 times UV and rain exposure to the humidity sensors at high RH, no significant change was detected in the resistance values of the humidity sensors. Moreover, some important features of the sensors such as hysteresis, repeatability, response time have been also examined. According to hysteresis test results, humidity sensors show acceptable dynamic response and response time of the sensors are 15.8, 17.3, 24.8, and 25 s at 100% RH for G2S, W1S, B2C, and W1C, respectively. Statistical analyses showed that the sensor designs and type of conductive inks had significant effects on the performance of the humidity sensors and the best sensor performance was obtained with the polypropylene coated fabric using design II and silver based conductive ink. The fabricated textile based flexible humidity sensors detect the change in RH levels from 80% RH to 100% RH and achieve good durability, and repeatability even after prolonged UV exposure and raining. Thus, the developed textile-based flexible humidity sensor might be useful for future smart agricultural applications.
{"title":"Flexible humidity sensor for smart agricultural applications","authors":"Meltem Tekçin, Damla Rabia Tuzer Hamzaoglu, S. Kursun","doi":"10.1088/2058-8585/ace8a6","DOIUrl":"https://doi.org/10.1088/2058-8585/ace8a6","url":null,"abstract":"In order to meet the increasing food demand, sensors that measure the ambient temperature and humidity in greenhouses are needed for more efficient vegetable and fruit production. For this purpose, two different flexible and resistant textile-based humidity sensors that can measure the humidity at higher levels (80%, 90%, and 100% relative humidity (RH)) were designed and printed directly on the four different greenhouse fabrics using silver and carbon conductive inks. Depending on the humidity value in the environment, the sensor performance was tested based on sensor electrical resistance measurements with respect to repeated bending/cyclic tests, rubbing, ultraviolet (UV) exposure/ weatherability (against UV and raining) tests in order to simulate greenhouse conditions for smart agriculture. Despite applying 1024 bending cycles, up to 20 rubbing cycles, and 10 times UV and rain exposure to the humidity sensors at high RH, no significant change was detected in the resistance values of the humidity sensors. Moreover, some important features of the sensors such as hysteresis, repeatability, response time have been also examined. According to hysteresis test results, humidity sensors show acceptable dynamic response and response time of the sensors are 15.8, 17.3, 24.8, and 25 s at 100% RH for G2S, W1S, B2C, and W1C, respectively. Statistical analyses showed that the sensor designs and type of conductive inks had significant effects on the performance of the humidity sensors and the best sensor performance was obtained with the polypropylene coated fabric using design II and silver based conductive ink. The fabricated textile based flexible humidity sensors detect the change in RH levels from 80% RH to 100% RH and achieve good durability, and repeatability even after prolonged UV exposure and raining. Thus, the developed textile-based flexible humidity sensor might be useful for future smart agricultural applications.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44365418","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 : 2023-07-11DOI: 10.1088/2058-8585/ace26b
Halil Tetik, Emmy Markgraf, Kohya Kato, Valerie N Chan, M. Malakooti
The rapid and simple fabrication process of laser-induced graphene (LIG) has enabled the creation of flexible sensors for emerging applications such as wearable electronics and intelligent systems. Although LIG can be designed to be a sensitive strain sensor due to the large change in its resistance under deformation, this property can also limit its use as a printed conductor on flexible substrates. Here, we present a versatile technique to enhance the electrical conductivity and resistive heating ability of LIG for use as flexible conductors in printed electronics. The highly conductive traces are prepared by direct writing of LIG onto a polyimide film using a CO2 laser, upon which the functionalized liquid metal (LM)—eutectic gallium indium (EGaIn)—particles are deposited and activated. This results in a ∼400 times increase in electrical conductivity of LIG traces while maintaining mechanical flexibility and manufacturing scalability without the need for soldering. Electromechanical characterization of the LIG-LM traces shows low resistance change (less than 0.3 Ω) under large bending deformations. At the same time, the enhanced electrical conductivity contributes to the resistive heating performance as it reduces the input voltage requirement by ∼15 times to achieve similar surface temperatures compared to pure LIG traces. By combining EGaIn LM with laser-synthesized graphene, we can fabricate flexible hybrid electronics. We demonstrate the practicality of this technique by fabrication of flexible conductors and heating devices with highly customizable patterns.
{"title":"Highly conductive laser-induced graphene through the deposition of liquid metal particles for flexible electronics","authors":"Halil Tetik, Emmy Markgraf, Kohya Kato, Valerie N Chan, M. Malakooti","doi":"10.1088/2058-8585/ace26b","DOIUrl":"https://doi.org/10.1088/2058-8585/ace26b","url":null,"abstract":"The rapid and simple fabrication process of laser-induced graphene (LIG) has enabled the creation of flexible sensors for emerging applications such as wearable electronics and intelligent systems. Although LIG can be designed to be a sensitive strain sensor due to the large change in its resistance under deformation, this property can also limit its use as a printed conductor on flexible substrates. Here, we present a versatile technique to enhance the electrical conductivity and resistive heating ability of LIG for use as flexible conductors in printed electronics. The highly conductive traces are prepared by direct writing of LIG onto a polyimide film using a CO2 laser, upon which the functionalized liquid metal (LM)—eutectic gallium indium (EGaIn)—particles are deposited and activated. This results in a ∼400 times increase in electrical conductivity of LIG traces while maintaining mechanical flexibility and manufacturing scalability without the need for soldering. Electromechanical characterization of the LIG-LM traces shows low resistance change (less than 0.3 Ω) under large bending deformations. At the same time, the enhanced electrical conductivity contributes to the resistive heating performance as it reduces the input voltage requirement by ∼15 times to achieve similar surface temperatures compared to pure LIG traces. By combining EGaIn LM with laser-synthesized graphene, we can fabricate flexible hybrid electronics. We demonstrate the practicality of this technique by fabrication of flexible conductors and heating devices with highly customizable patterns.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48546083","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 : 2023-07-07DOI: 10.1088/2058-8585/ace53a
Y. Chang, H. Liu, Bo-Jhang Chen
Potential applications of natural materials in environmentally friendly electronics include for information storage. In this work, natural material–agar was used to fabricate a flexible resistive memory device. Agar is one of the most widely used biomaterials for tissue engineering, medicine and other biotechnological applications. Agar is a suitable material for flexible electronics due to its good film formation, biocompatibility, low-temperature solution processability, transparency and flexibility. The flexible agar memory device described in this article exhibits an ON/OFF ratio of 103 under a bending radius of 5 mm, good bending endurance and a stable data retention time of over 104 s. Moreover, the agar could easily use a leaf as a substrate to make a fully biodegradable device. Agar, due to its exceptional flexibility, is emerging as a promising candidate for wearable and skin-compatible electronics, particularly in memory devices.
{"title":"Flexible resistive memory device based on agar","authors":"Y. Chang, H. Liu, Bo-Jhang Chen","doi":"10.1088/2058-8585/ace53a","DOIUrl":"https://doi.org/10.1088/2058-8585/ace53a","url":null,"abstract":"Potential applications of natural materials in environmentally friendly electronics include for information storage. In this work, natural material–agar was used to fabricate a flexible resistive memory device. Agar is one of the most widely used biomaterials for tissue engineering, medicine and other biotechnological applications. Agar is a suitable material for flexible electronics due to its good film formation, biocompatibility, low-temperature solution processability, transparency and flexibility. The flexible agar memory device described in this article exhibits an ON/OFF ratio of 103 under a bending radius of 5 mm, good bending endurance and a stable data retention time of over 104 s. Moreover, the agar could easily use a leaf as a substrate to make a fully biodegradable device. Agar, due to its exceptional flexibility, is emerging as a promising candidate for wearable and skin-compatible electronics, particularly in memory devices.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47796820","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}
Paper-based analytical devices are a strong candidate for development due to the global need for accurate, easy-to-use, and cost-effective tools. Paper offers potential as a substrate for biomedical diagnostic devices, but on its own it is limited in versatility. By combining paper with hydrogel, researchers are able to improve automation, sensitivity, affordability, flexibility, and speed. Hydrogel, a highly biocompatible material, enhances fluid flow control and the biocompatibility of paper for functional interaction with biomolecules. Hydrogel-coated paper has been utilized for various applications, including separation and detection, microfluidics, and cell culture. Here we summarize the paper-based analytical tools with hydrogel incorporated into the paper substrate for biomedical purposes. The use of hydrogel-coated paper offers new opportunities for advanced analytical tools with improved sensitivity and functionality.
{"title":"Extended functionalities of paper-based analytical devices using hydrogels for biomedical applications","authors":"Ignasia Handipta Mahardika, Sarath Kin, Oh-Sun Kwon, Kwanwoo Shin","doi":"10.1088/2058-8585/ace4da","DOIUrl":"https://doi.org/10.1088/2058-8585/ace4da","url":null,"abstract":"Paper-based analytical devices are a strong candidate for development due to the global need for accurate, easy-to-use, and cost-effective tools. Paper offers potential as a substrate for biomedical diagnostic devices, but on its own it is limited in versatility. By combining paper with hydrogel, researchers are able to improve automation, sensitivity, affordability, flexibility, and speed. Hydrogel, a highly biocompatible material, enhances fluid flow control and the biocompatibility of paper for functional interaction with biomolecules. Hydrogel-coated paper has been utilized for various applications, including separation and detection, microfluidics, and cell culture. Here we summarize the paper-based analytical tools with hydrogel incorporated into the paper substrate for biomedical purposes. The use of hydrogel-coated paper offers new opportunities for advanced analytical tools with improved sensitivity and functionality.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45285949","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}
In this study, software and hardware that supported automatic optical inspection (AOI) for printed circuit board production line was proposed and demonstrated. The proposed method showed an effective solution that predicts off-line electromagnetic (EM) characteristic of manufactured components through in-line pattern integrity. A spiral antenna that represented complex patterns was used as the evaluation target with imitated production variations. Numerical evaluation on EM properties, batch fabrication, hardware setup and optimization, algorithm and graphical user interface development, machine learning and artificial intelligence modeling, and data verification and analysis were thoroughly conducted in this study. Results indicated that when the antenna showed pattern distortion, its passive capacitance, active intensity, and active frequency increased, decreased, and decreased, respectively. These results proved that the developed system and method overcame the inability of in-line EM measurement in conventional setup. The results also showed high estimation accuracy that was not yet achieved in the past. Compared to existing or similar AOI ideas, the proposed method supports analyses on complex pattern, provides solutions on target design, and efficient algorithm generation. This work also proved active and passive EM signals with evidences, and exhibited outstanding confidence levels for characteristic estimations. The proposed system and method indicated their potential in smart manufacturing.
{"title":"Machine-learning based characteristic estimation method in printed circuit board production lines","authors":"Mu-Lin Tsai, Rong-Qing Qiu, Kuan-Yi Wu, Tzu-Hsuan Hsu, Ming-Huang Li, Cheng-Yao Lo","doi":"10.1088/2058-8585/ace4db","DOIUrl":"https://doi.org/10.1088/2058-8585/ace4db","url":null,"abstract":"In this study, software and hardware that supported automatic optical inspection (AOI) for printed circuit board production line was proposed and demonstrated. The proposed method showed an effective solution that predicts off-line electromagnetic (EM) characteristic of manufactured components through in-line pattern integrity. A spiral antenna that represented complex patterns was used as the evaluation target with imitated production variations. Numerical evaluation on EM properties, batch fabrication, hardware setup and optimization, algorithm and graphical user interface development, machine learning and artificial intelligence modeling, and data verification and analysis were thoroughly conducted in this study. Results indicated that when the antenna showed pattern distortion, its passive capacitance, active intensity, and active frequency increased, decreased, and decreased, respectively. These results proved that the developed system and method overcame the inability of in-line EM measurement in conventional setup. The results also showed high estimation accuracy that was not yet achieved in the past. Compared to existing or similar AOI ideas, the proposed method supports analyses on complex pattern, provides solutions on target design, and efficient algorithm generation. This work also proved active and passive EM signals with evidences, and exhibited outstanding confidence levels for characteristic estimations. The proposed system and method indicated their potential in smart manufacturing.","PeriodicalId":51335,"journal":{"name":"Flexible and Printed Electronics","volume":" ","pages":""},"PeriodicalIF":3.1,"publicationDate":"2023-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43208080","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}
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