Frontiers in electronics最新文献

{"title":"Morphological and Optical Tuning of Lead-Free Cs 2 SnX 6 (X = I, Br) Perovskite Nanocrystals by Ligand Engineering","authors":"A. Veronese, Carlo Ciarrocchi, M. Marelli, P. Quadrelli, M. Patrini, L. Malavasi","doi":"10.3389/felec.2021.703182","DOIUrl":"https://doi.org/10.3389/felec.2021.703182","url":null,"abstract":"In order to overcome the toxicity of lead halide perovskites, in recent years the research has focused on replacing lead with more environmentally friendly metals like tin, germanium, bismuth or antimony. However, lead-free perovskites still present instability issues and low performances that do not make them competitive when compared to their lead-based counterparts. Here we report the synthesis of lead-free Cs2SnX6 (X = Br, I) nanostructures of different shapes by using various surface ligands. These compounds are a promising alternative to lead halide perovskites in which the replacement of divalent lead (Pb(II)) with tetravalent tin (Sn(IV)) causes a modification of the standard perovskite structure. We investigate the effects of different amines on the morphology and size of Cs2SnX6 (X = Br, I) nanocrystals, presenting a facile hot-infection method to directly synthesize three-dimensional (3D) nanoparticles as well as two-dimensional (2D) nanoplatelets. The amines not only modify the shape of the crystals, but also affect their optical properties: increasing the length of the amine carbon chain we observe a widening in the bandgap of the compounds and a blue-shift of their emission peak. Alongside the tuning of the chemical composition and the reduction of the crystal size, our study offers a new insight in controlling the physical properties of perovskite nanocrystals by means of the capping ligands, paving the way for future research on lead-free materials.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46391973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Motion Artifact Removal Techniques for Wearable EEG and PPG Sensor Systems","authors":"D. Seok, Sanghyun Lee, Minjae Kim, Jaeouk Cho, Chul Kim","doi":"10.3389/felec.2021.685513","DOIUrl":"https://doi.org/10.3389/felec.2021.685513","url":null,"abstract":"Removal of motion artifacts is a critical challenge, especially in wearable electroencephalography (EEG) and photoplethysmography (PPG) devices that are exposed to daily movements. Recently, the significance of motion artifact removal techniques has increased since EEG-based brain–computer interfaces (BCI) and daily healthcare usage of wearable PPG devices were spotlighted. In this article, the development on EEG and PPG sensor systems is introduced. Then, understanding of motion artifact and its reduction methods implemented by hardware and/or software fashions are reviewed. Various electrode types, analog readout circuits, and signal processing techniques are studied for EEG motion artifact removal. In addition, recent in-ear EEG techniques with motion artifact reduction are also introduced. Furthermore, techniques compensating independent/dependent motion artifacts are presented for PPG.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48961614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grand Challenges in Wearable Electronics","authors":"E. Sazonov, W. Daoud","doi":"10.3389/felec.2021.668619","DOIUrl":"https://doi.org/10.3389/felec.2021.668619","url":null,"abstract":"Wearable technology has deep roots in history, with eyeglasses and wrist and pocket watches being two of the most prolific technologies still being in use today. These technologies developed and evolved over the centuries. For example, watches started as decorative pieces based on an oscillating wheel and gear mechanism, later acquiring a primitive form of energy harvesting (selfwinding), progressing to electromechanical and then to fully electronic devices (McCrossen, 2013). Future watches may integrate sophisticated electronics, solar or thermal energy harvesting, carry a huge variety of functions beyond timekeeping and still be a decoration and a fashion statement. Eyeglasses is another vivid example, starting as assistive technology (Letocha and Dreyfus, 2002), also evolving to become a fashion accessory, frequently used by individuals who do not need vision correction. Eyeglasses are rapidly becoming a high-tech electronic device, with Google Glass, Alexa Frames, and the likes paving the way to everyday use of augmented reality. The long-term success of these two technologies is based on their utility, deep integration with daily activities, and social acceptance by the population (Degerli and Ozkan Yildirim, 2020). These examples are very valuable when we consider the challenges facing wearable electronics today. Future growth in wearable devices is tightly coupled with advances in semiconductor technology and electronics. Wearables integrate a power source, sensors, data processing and storage core, actuators and displays, and a communication interface, packaged in a small, lightweight device that is worn on the body or integrated with everyday wear items, such as clothing, footwear, or accessories. Such wearables exemplify the cutting edge of the electronics, demanding the highest performance for the least amount of power, in the least amount of space, and in a challenging operating environment. Here wearables may gain a valuable lesson from a recent success story– the emergence of the smartphone as a ubiquitous communication device. The demands of modern smartphones closely match those of wearable devices, albeit in a larger package. The driving force behind the innovation andminiaturization of smartphones is high acceptability and demand across different cultures, generations, and societies. Resonating with the success of watches and eyeglasses, smartphones have a great utility that is tightly integrated into our life. Wearables may just as well become the next success story if they find an application that is demanded by the masses and if the electronic technology can support the effortless integration of wearables into the daily routine. Looking into the electronic technologies that form the foundation of wearable devices, we can highlight several distinct areas:","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45090165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved Stability of Organic Photovotlaic Devices With FeCl3 Intercalated Graphene Electrodes","authors":"Kieran K. Walsh, Conor N. Murphy, S. Russo, M. Craciun","doi":"10.3389/felec.2021.643687","DOIUrl":"https://doi.org/10.3389/felec.2021.643687","url":null,"abstract":"In this paper, we present the first organic photovoltaic (OPV) devices fabricated with FeCl3 intercalated few layer graphene (i-FLG) electrodes. i-FLG electrodes were first fabricated and characterized by electrical and spectroscopic means, showing enhanced conductive properties compared to pristine graphene. These electrodes were then used in the fabrication of OPV devices and tested against devices made with commercially available Indium Tin Oxide (ITO) electrodes. Both types of device achieved similar efficiencies, while the i-FLG based device exhibited superior charge transport properties due to the increase in work function characterizing i-FLG. Both types of device underwent a stability study using both periodic and continuous illumination measurements, which revealed i-FLG based OPVs to be significantly more stable than those based on ITO. These improvements are expected to translate to increased device lifetimes and a greater total energy payback from i-FLG based photovoltaic devices. These results highlight the potential benefits of using intercalated graphene materials as an alternative to ITO in photovoltaic devices.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45472902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-Time Dispatching Performance Improvement of Multiple Multi-Energy Supply Microgrids Using Neural Network Based Approximate Dynamic Programming","authors":"Bei Li, R. Roche","doi":"10.3389/felec.2021.637736","DOIUrl":"https://doi.org/10.3389/felec.2021.637736","url":null,"abstract":"In the multi-energy supply microgrid, different types of energy can be scheduled from a “global” view, which can improve the energy utilization efficiency. In addition, hydrogen storage system performs as the long-term storage is considered, which can promote more renewable energy installed in the local consumer side. However, when there are large numbers of grid-connected multi-energy microgrids, the scheduling of these multiple microgrids in real-time is a problem. Because different types of devices, three types of energy, and three types of utility grid networks are considered, which make the dispatching problem difficult. In this paper, a two-stage coordinated algorithm is adopted to operate the microgrids: day-ahead scheduling and real-time dispatching. In order to reduce the time taken to solve the scheduling problem, and improve the scheduling performance, approximate dynamic programming (ADP) is used in real-time operation. Different types of value function approximations (VFA), i.e., linear function, nonlinear function, and neural network are compared to study about the influence of the VFA on the decision results. Offline and online processes are developed to study the impact of the historical data on the regression of VFA. The results show that the neural network based ADP one-step decision algorithm has almost the same performance as the Global optimization algorithm, and the highest performance among all others Local optimization algorithms. The total operation cost relative error is less than 3%, while the running time is only 31% of the Global algorithm. In the neural network based ADP, the key technology is continuously updating the training dataset online, and adopting an appropriate neural network structure, which can at last improve the scheduling performance.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44944335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flexible Electronics: Status, Challenges and Opportunities","authors":"Daniel Corzo, Guillermo Tostado-Blázquez, D. Baran","doi":"10.3389/felec.2020.594003","DOIUrl":"https://doi.org/10.3389/felec.2020.594003","url":null,"abstract":"The concept of flexible electronics has been around for several decades. In principle, anything thin or very long can become flexible. While cables and wiring are the prime example for flexibility, it was not until the space race that silicon wafers used for solar cells in satellites were thinned to increase their power per weight ratio, thus allowing a certain degree of warping. This concept permitted the first flexible solar cells in the 1960s (Crabb and Treble, 1967). The development of conductive polymers (Shirakawa et al., 1977), organic semiconductors, and amorphous silicon (Chittick et al., 1969; Okaniwa et al., 1983) in the following decades meant huge strides toward flexibility and processability, and thus these materials became the base for electronic devices in applications that require bending, rolling, folding, and stretching, among other properties that cannot be fulfilled by conventional electronics (Cheng and Wagner, 2009) (Figure 1). Presently there is great interest in new materials and fabrication techniques which allow for highperformance scalable electronic devices to be manufactured directly onto flexible substrates. This interest has also extended to not only flexibility but also properties like stretchability and healability which can be achieved by utilizing elastomeric substrates with strong molecular interactions (Oh et al., 2016; Kang et al., 2018). Likewise, biocompatibility and biodegradability has been achieved through polymers that do not cause adverse effect to the body and can be broken down into smaller constituent pieces after utilization (Bettinger and Bao, 2010; Irimia-Vladu et al., 2010; Liu H. et al., 2019). This new progress is now enabling devices which can conform to complex and dynamic surfaces, such as those found in biological systems and bioinspired soft robotics. These next-generation flexible electronics open up a wide range of exciting new applications such as flexible lighting and display technologies for consumer electronics, architecture, and textiles, wearables with sensors that help monitor our health and habits, implantable electronics for improved medical imaging and diagnostics, as well as extending the functionality of robots and unmanned aircraft through lightweight and conformable energy harvesting devices and sensors. While conventional electronics are very capable of these functions, flexible electronics are intended to expand the mechanical features to adhere to novel form factors through hybrid strategies, or as standalone solutions where the application does not require high computation power, intended to be highly robust to deformation, low cost, thin, or disposable. The definition of flexibility differs from application to application. From bending and rolling for easier handling of large area photovoltaics, to conforming onto irregular shapes, folding, twisting, stretching, and deforming required for devices in electronic skin, all while maintaining device performance and reliab","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3389/felec.2020.594003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41421304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Specialty Grand Challenges in Optoelectronics","authors":"A. Abate","doi":"10.3389/felec.2020.579890","DOIUrl":"https://doi.org/10.3389/felec.2020.579890","url":null,"abstract":"In 1638, the Italian astronomer Galileo Galilei designed one of the first experiments attempting to measure the speed of light (Foschi and Leone, 2009). Although the test was not conclusive, it reinforced the hypothesis that light could have a finite speed. The speed limit was one of the key steps toward understanding the elusive nature of light and the complex phenomena that surrounds lightmatter interaction. Much later, it was demonstrated that when light (and any electromagnetic radiation in general) interacts with matter, it might induce a flow of electrons. Symmetrically, a flow of electrons within matter might generate electromagnetic radiation. We call optoelectronics “the study and the application of the phenomena, materials, and devices involved with the interaction between electrons within a material or a device and the absorption or emission of electromagnetic radiation from the same” (Koch, 2014). Optoelectronic is essential in modern life, and it will become increasingly more important in future because technological development is relying more and more on the diffusion of devices that source, detect, and control electromagnetic radiation. X-ray, ultraviolet, visible, and infrared light optoelectronics are the most relevant. They are involved in a large number of applications in many relevant fields of technological development, including but not limited to Energy, Medicine, Architecture, Communication, Robotics, Transport, Security, and Entertainment. Below we report some examples of applications representative of the fields listed above (Figure 1).","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3389/felec.2020.579890","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48566846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance and Signal Quality Analysis of Electrocardiogram Textile Electrodes for Smart Apparel Applications","authors":"Katherine Le, A. Servati, S. Soltanian, P. Servati, F. Ko","doi":"10.1109/IFETC46817.2019.9073686","DOIUrl":"https://doi.org/10.1109/IFETC46817.2019.9073686","url":null,"abstract":"Electronic textile (e-textile) systems applied to biological signal monitoring are of great interest to the healthcare industry, given the potential to provide continuous and long-term monitoring of healthy individuals and patients. Most developments in e-textiles have focused on novel materials and systems without systematic considerations into how the hierarchical structure of fibrous assemblies may influence performance and compatibility of the materials during use. This study examines mechanisms underlying the stability and quality of textile-based electrocardiogram (ECG) electrodes used in a smart bra. Signal quality of the biometric data obtained affects feedback and user experience and may be influenced by characteristics and properties of the material. Under stationary and dynamic conditions, analysis of the raw ECG signal and heart rate, with respect to textile-electrode material properties have been performed. Currently, there is no standardized procedure to compare the ECG signal between electrode materials. In this study, several methods have been applied to compare differences between silver-based textile electrodes and silver/silver-chloride gel electrodes. The comparison methods serve to complement visual observations of the ECG signal acquired, as possible quantitative means to differentiate electrode materials and their performance. From the results obtained, signal quality, and heart rate (HR) detection were found to improve with increased skin contact, and textile structures with lower stretch and surface resistance, especially under dynamic/movement test conditions. It was found that the performance of the textile electrode materials compared exceeded ECG signal quality thresholds previously established for acceptable signal quality, specifically for the kurtosis (K > 5), and Pearson correlation coefficients (r ≥ 0.66) taken from average ECG waveforms calculated.","PeriodicalId":73081,"journal":{"name":"Frontiers in electronics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/IFETC46817.2019.9073686","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42818856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}