Yue Liu, Huayu Xu, Ming Dong, Renhou Han, J. Tao, Rongrong Bao, Caofeng Pan
Flexible electronic equipment is an emerging field in recent years, which attaches more attention to be researched and applied in health monitoring and human–machine interface. However, for the existing pressure sensors, even a very slight pressure will greatly reduce their sensitivity, so it is an urgent problem to be solved for achieving high sensitivity and wide application range simultaneously. Hence, a high‐performance piezoresistive pressure sensor based on PAN nanofiber films (PAN NFs) and MXene (Ti3C2Tx) is proposed. The realization of high sensitivity and wide sensing range is based on the microstructure of accordion‐like MXene and the macrostructure of fluffy porous blowing spinning PAN nanofibers, which exhibits a high sensitivity of 81.89 kPa−1 over a wide sensing range of 0.83–38.13 kPa and the dynamic responses to external pressures can reach 98.73 kPa. The pressure sensors based on skin surface‐like 3D patterned interwoven structure are used for health monitoring and tiny pressure detecting. Moreover, the application in human–machine interface is demonstrated. Additionally, to meet the requirement of long‐term wearing, the structure of the sensor is optimized and endowed with excellent breathability and conformal properties, which promotes the further development of flexible electronic equipment.
{"title":"Highly Sensitive Wearable Pressure Sensor Over a Wide Sensing Range Enabled by the Skin Surface‐Like 3D Patterned Interwoven Structure","authors":"Yue Liu, Huayu Xu, Ming Dong, Renhou Han, J. Tao, Rongrong Bao, Caofeng Pan","doi":"10.1002/admt.202200504","DOIUrl":"https://doi.org/10.1002/admt.202200504","url":null,"abstract":"Flexible electronic equipment is an emerging field in recent years, which attaches more attention to be researched and applied in health monitoring and human–machine interface. However, for the existing pressure sensors, even a very slight pressure will greatly reduce their sensitivity, so it is an urgent problem to be solved for achieving high sensitivity and wide application range simultaneously. Hence, a high‐performance piezoresistive pressure sensor based on PAN nanofiber films (PAN NFs) and MXene (Ti3C2Tx) is proposed. The realization of high sensitivity and wide sensing range is based on the microstructure of accordion‐like MXene and the macrostructure of fluffy porous blowing spinning PAN nanofibers, which exhibits a high sensitivity of 81.89 kPa−1 over a wide sensing range of 0.83–38.13 kPa and the dynamic responses to external pressures can reach 98.73 kPa. The pressure sensors based on skin surface‐like 3D patterned interwoven structure are used for health monitoring and tiny pressure detecting. Moreover, the application in human–machine interface is demonstrated. Additionally, to meet the requirement of long‐term wearing, the structure of the sensor is optimized and endowed with excellent breathability and conformal properties, which promotes the further development of flexible electronic equipment.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78555900","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}
Peikai Zhang, Bicheng Zhu, Yufei Luo, J. Travas-sejdic
Electrically driven actuators have found widespread applications in biomimetics and soft robotics. Among different actuation materials, conducting polymers (CPs) have stood out due to their unique doping‐based actuation mechanism. Fabricating actuators at the microscale is particularly important, not only in the manufacturing of delicate biomimetic/robotic devices but also in advanced microphysiological studies. However, the choice for microfabrication techniques is limited, with the reported CP microactuators being mainly planar. To overcome this issue, a new micropipette‐based method is developed for the fabrication of free‐standing 3D CP actuators. The two‐layer actuator consists of a layer of PPy:CF3SO3, fabricated by localized electropolymerization, and a layer of PEDOT:PSS, fabricated by a “direct writing” technique. Due to the opposite contraction and expansion behavior of these two CPs, determined by the size of dopants, the electrically driven bending actuators have been demonstrated. This fabrication approach provides unprecedented capability for fabricating high aspect ratio microactuators: the 360° bending orientation of the actuators can be controlled by the relative position of the two layers. As a proof‐of‐principle, we demonstrate CP “micro‐tweezers” and the manipulation of a PDMS microsphere. The technique developed in this work opens exciting opportunities to manufacture advanced artificial muscles and sophisticated soft microrobotics.
{"title":"Micropipette‐Based Fabrication of Free‐Standing, Conducting Polymer Bilayer Actuators","authors":"Peikai Zhang, Bicheng Zhu, Yufei Luo, J. Travas-sejdic","doi":"10.1002/admt.202200686","DOIUrl":"https://doi.org/10.1002/admt.202200686","url":null,"abstract":"Electrically driven actuators have found widespread applications in biomimetics and soft robotics. Among different actuation materials, conducting polymers (CPs) have stood out due to their unique doping‐based actuation mechanism. Fabricating actuators at the microscale is particularly important, not only in the manufacturing of delicate biomimetic/robotic devices but also in advanced microphysiological studies. However, the choice for microfabrication techniques is limited, with the reported CP microactuators being mainly planar. To overcome this issue, a new micropipette‐based method is developed for the fabrication of free‐standing 3D CP actuators. The two‐layer actuator consists of a layer of PPy:CF3SO3, fabricated by localized electropolymerization, and a layer of PEDOT:PSS, fabricated by a “direct writing” technique. Due to the opposite contraction and expansion behavior of these two CPs, determined by the size of dopants, the electrically driven bending actuators have been demonstrated. This fabrication approach provides unprecedented capability for fabricating high aspect ratio microactuators: the 360° bending orientation of the actuators can be controlled by the relative position of the two layers. As a proof‐of‐principle, we demonstrate CP “micro‐tweezers” and the manipulation of a PDMS microsphere. The technique developed in this work opens exciting opportunities to manufacture advanced artificial muscles and sophisticated soft microrobotics.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89361045","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}
Longsheng Lu, D. Zhang, Yingxi Xie, Heng-fei He, Wentao Wang
Latest advances have witnessed the laser scribing of various active materials from synthetic polymers to natural sources without masks, post‐treatment, or toxic substances. However, laser induced graphene (LIG) on renewable precursors usually requires flame‐retardant pretreatment and multistep pulsed or defocused irradiation. Laser scribing of silicon carbide (SiC) from polydimethylsiloxane (PDMS) is limited by its high transparency over a broad wavelength range. Here, a structural design strategy is adopted to solve these two dilemmas at the same time, that is, laser scribing of carbonized cloth/PDMS to prepare LIG/SiC composites. Natural cotton cloth is precarbonized and inserted in PDMS substrate to facilitate heat absorption for the in situ formation of SiC, while the soft PDMS attached to the carbonized cloth absorbs heat and isolates oxygen, enabling the conversion of amorphous carbon to LIG. Under these multifield coupling effects, a core–shell LIG/SiC electrode is formed on the carbonized cloth with tunable mass ratio, morphology, and graphene defects. Experimentally, the LIG/SiC pressure sensor exhibits a good sensitivity of 1.91 kPa−1 in the super‐wide sensing range of 0–226.7 kPa. By demonstrating different scenarios such as real‐time monitoring of large body movements, tiny pulses and heartbeats, the flexible pressure sensors hold great promise in wearable electronics.
{"title":"Laser Induced Graphene/Silicon Carbide: Core–Shell Structure, Multifield Coupling Effects, and Pressure Sensor Applications","authors":"Longsheng Lu, D. Zhang, Yingxi Xie, Heng-fei He, Wentao Wang","doi":"10.1002/admt.202200441","DOIUrl":"https://doi.org/10.1002/admt.202200441","url":null,"abstract":"Latest advances have witnessed the laser scribing of various active materials from synthetic polymers to natural sources without masks, post‐treatment, or toxic substances. However, laser induced graphene (LIG) on renewable precursors usually requires flame‐retardant pretreatment and multistep pulsed or defocused irradiation. Laser scribing of silicon carbide (SiC) from polydimethylsiloxane (PDMS) is limited by its high transparency over a broad wavelength range. Here, a structural design strategy is adopted to solve these two dilemmas at the same time, that is, laser scribing of carbonized cloth/PDMS to prepare LIG/SiC composites. Natural cotton cloth is precarbonized and inserted in PDMS substrate to facilitate heat absorption for the in situ formation of SiC, while the soft PDMS attached to the carbonized cloth absorbs heat and isolates oxygen, enabling the conversion of amorphous carbon to LIG. Under these multifield coupling effects, a core–shell LIG/SiC electrode is formed on the carbonized cloth with tunable mass ratio, morphology, and graphene defects. Experimentally, the LIG/SiC pressure sensor exhibits a good sensitivity of 1.91 kPa−1 in the super‐wide sensing range of 0–226.7 kPa. By demonstrating different scenarios such as real‐time monitoring of large body movements, tiny pulses and heartbeats, the flexible pressure sensors hold great promise in wearable electronics.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90524580","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}
Barbara Wilk, S. Sahayaraj, M. Ziółek, Vivek Babu, R. Kudrawiec, K. Wojciechowski
Metal halide perovskites of reduced dimensionality constitute an interesting subcategory of the perovskite semiconductor family, which attract a lot of attention, primarily due to their excellent moisture resistance and peculiar optoelectronic properties. Specifically, quasi‐2D materials of the Ruddlesden–Popper (RP) type, are intensely investigated as photoactive layers in perovskite solar cells. Here, a scalable deposition of quasi‐2D perovskite thin films, with a nominal composition of 4F‐PEA2MA4Pb5I16 (4‐FPEA+‐4‐fluoro‐phenethylammonium, applied as a spacer cation), using an inkjet printing technique, is developed. An optimized precursor formulation, and appropriate post‐printing treatment, which enable good control over nucleation and crystal growth steps, result in highly crystalline and uniform perovskite layers. Particularly, vacuum with nitrogen flushing provides an optimal drying treatment, which produces a more uniform distribution of low dimensional phases, and a high level of vertical (out‐of‐plane) alignment, which is beneficial for charge carrier transport. Solar cells reaching 13% of power conversion efficiency for the rigid, and 10.6% for the flexible, large area (1 cm2) devices are presented.
{"title":"Inkjet Printing of Quasi‐2D Perovskite Layers with Optimized Drying Protocol for Efficient Solar Cells","authors":"Barbara Wilk, S. Sahayaraj, M. Ziółek, Vivek Babu, R. Kudrawiec, K. Wojciechowski","doi":"10.1002/admt.202200606","DOIUrl":"https://doi.org/10.1002/admt.202200606","url":null,"abstract":"Metal halide perovskites of reduced dimensionality constitute an interesting subcategory of the perovskite semiconductor family, which attract a lot of attention, primarily due to their excellent moisture resistance and peculiar optoelectronic properties. Specifically, quasi‐2D materials of the Ruddlesden–Popper (RP) type, are intensely investigated as photoactive layers in perovskite solar cells. Here, a scalable deposition of quasi‐2D perovskite thin films, with a nominal composition of 4F‐PEA2MA4Pb5I16 (4‐FPEA+‐4‐fluoro‐phenethylammonium, applied as a spacer cation), using an inkjet printing technique, is developed. An optimized precursor formulation, and appropriate post‐printing treatment, which enable good control over nucleation and crystal growth steps, result in highly crystalline and uniform perovskite layers. Particularly, vacuum with nitrogen flushing provides an optimal drying treatment, which produces a more uniform distribution of low dimensional phases, and a high level of vertical (out‐of‐plane) alignment, which is beneficial for charge carrier transport. Solar cells reaching 13% of power conversion efficiency for the rigid, and 10.6% for the flexible, large area (1 cm2) devices are presented.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79944519","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}
R. Granberry, Megan Clarke, R. Pettys-Baker, Heidi Woelfle, Crystal Compton, Amy Ross, Kirstyn M. Johnson, S. Padula, Surbhi Shah, J. Abel, B. Holschuh
New medical compression technologies that are simultaneously low‐profile, facile to don, and dynamic—applying medical compression only when needed—can expand the use of wearable compression, increase patient compliance, and lead to better medical outcomes. Dynamic and conformal wearable compression devices are presented that can be donned in a low‐stiffness state and transition into a high‐stiffness and, consequently, high‐compression state, on‐demand. These devices are enabled by active textiles developed from custom NiTi filaments that remain inactive at room temperature and accomplish actuation proximal to the human body surface. Further, these compression devices exploit NiTi material hysteresis to sustain a high‐compression state post‐heating and upon equilibrium with the body surface temperature for thermally‐comfortable, on‐body performance. Two case study examples—1) a consumer medical compression device and 2) a custom astronaut compression device—demonstrate the generalizability and flexibility of the engineering and design methods to develop a range of dynamic, tunable, and conformal compression devices with different goals and requirements. Further, this work demonstrates a roadmap for developing wearable systems that can accommodate a range of users without sacrificing system performance. This research opens doors for new NiTi‐based medical and consumer applications that interface with the body surface.
{"title":"Dynamic, Tunable, and Conformal Wearable Compression Using Active Textiles","authors":"R. Granberry, Megan Clarke, R. Pettys-Baker, Heidi Woelfle, Crystal Compton, Amy Ross, Kirstyn M. Johnson, S. Padula, Surbhi Shah, J. Abel, B. Holschuh","doi":"10.1002/admt.202200467","DOIUrl":"https://doi.org/10.1002/admt.202200467","url":null,"abstract":"New medical compression technologies that are simultaneously low‐profile, facile to don, and dynamic—applying medical compression only when needed—can expand the use of wearable compression, increase patient compliance, and lead to better medical outcomes. Dynamic and conformal wearable compression devices are presented that can be donned in a low‐stiffness state and transition into a high‐stiffness and, consequently, high‐compression state, on‐demand. These devices are enabled by active textiles developed from custom NiTi filaments that remain inactive at room temperature and accomplish actuation proximal to the human body surface. Further, these compression devices exploit NiTi material hysteresis to sustain a high‐compression state post‐heating and upon equilibrium with the body surface temperature for thermally‐comfortable, on‐body performance. Two case study examples—1) a consumer medical compression device and 2) a custom astronaut compression device—demonstrate the generalizability and flexibility of the engineering and design methods to develop a range of dynamic, tunable, and conformal compression devices with different goals and requirements. Further, this work demonstrates a roadmap for developing wearable systems that can accommodate a range of users without sacrificing system performance. This research opens doors for new NiTi‐based medical and consumer applications that interface with the body surface.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"78 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80811322","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}
Churong Ma, Fangrong Zhou, Pengfei Huang, Mengmeng Li, Feng Zhao, Yingqi Liu, Chun Du, Xiang Li, B. Guan, Kai Chen
High‐index all‐dielectric resonators have been developed into an important platform for light manipulation at the nanoscale over the past decade. Although they are widely used as 2D materials, transition metal dichalcogenides (TMDCs), as an emerging all‐dielectric material, have also been used to fabricate optical nanoantennas that support multipolar Mie resonances. However, their fabrication depends heavily on electron‐beam lithography (EBL) or focused ion beam (FIB), which is expensive and time‐consuming for practical applications. To address this issue, here, a fast low‐cost method is put forward which combines polystyrene (PS) nanospheres with physical vapor deposition by electron‐beam evaporation and magnetron sputtering to fabricate WS2 nanodisks in a mass‐production manner. After annealing, the A‐ and B‐exciton features as well as anapole states are observed in the scattering spectra of WS2 nanodisks. The light scattering anisotropy of individual WS2 nanodisks and spectral tunability of the anapole are studied. In addition, absorption enhancement due to the strong field localization of anapole states in hexagonal WS2 nanodisk arrays is numerically demonstrated. This work manifests that this etching‐free method is promising for fabrication of scalable TMDC nanodisks suitable for practical applications.
{"title":"Mass Fabrication of WS2 Nanodisks and their Scattering Properties","authors":"Churong Ma, Fangrong Zhou, Pengfei Huang, Mengmeng Li, Feng Zhao, Yingqi Liu, Chun Du, Xiang Li, B. Guan, Kai Chen","doi":"10.1002/admt.202200432","DOIUrl":"https://doi.org/10.1002/admt.202200432","url":null,"abstract":"High‐index all‐dielectric resonators have been developed into an important platform for light manipulation at the nanoscale over the past decade. Although they are widely used as 2D materials, transition metal dichalcogenides (TMDCs), as an emerging all‐dielectric material, have also been used to fabricate optical nanoantennas that support multipolar Mie resonances. However, their fabrication depends heavily on electron‐beam lithography (EBL) or focused ion beam (FIB), which is expensive and time‐consuming for practical applications. To address this issue, here, a fast low‐cost method is put forward which combines polystyrene (PS) nanospheres with physical vapor deposition by electron‐beam evaporation and magnetron sputtering to fabricate WS2 nanodisks in a mass‐production manner. After annealing, the A‐ and B‐exciton features as well as anapole states are observed in the scattering spectra of WS2 nanodisks. The light scattering anisotropy of individual WS2 nanodisks and spectral tunability of the anapole are studied. In addition, absorption enhancement due to the strong field localization of anapole states in hexagonal WS2 nanodisk arrays is numerically demonstrated. This work manifests that this etching‐free method is promising for fabrication of scalable TMDC nanodisks suitable for practical applications.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84000914","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}
Lei Zheng, N. Keppler, Huajun Zhang, Peter Behrens, B. Roth
An easily fabricated gas sensor based on planar polymer optical waveguides with an integrated zeolite imidazole framework‐8 (ZIF‐8) thin film is presented for carbon dioxide detection and sensing. The planar optical waveguides are made of polymethylmethacrylate and fabricated by hot embossing, which makes it flexible and cost‐efficient. Thin ZIF‐8 films are uniformly grown on the waveguides surface through a simple solution method, which is crucial for the envisioned production of metal organic framework‐based sensing devices on a large scale. Experimental results show that the produced optical elements exhibit a sensitivity of ≈2.5 μW/5 vol% toward carbon dioxide (CO2) with very rapid response time (≈6 s) and excellent reversibility of adsorption and desorption of the gas molecules. The demonstrated planar polymer sensing devices provide the potential to develop flexible on‐chip gas sensors in an inexpensive and reproducible way.
{"title":"Planar Polymer Optical Waveguide with Metal‐Organic Framework Coating for Carbon Dioxide Sensing","authors":"Lei Zheng, N. Keppler, Huajun Zhang, Peter Behrens, B. Roth","doi":"10.1002/admt.202200395","DOIUrl":"https://doi.org/10.1002/admt.202200395","url":null,"abstract":"An easily fabricated gas sensor based on planar polymer optical waveguides with an integrated zeolite imidazole framework‐8 (ZIF‐8) thin film is presented for carbon dioxide detection and sensing. The planar optical waveguides are made of polymethylmethacrylate and fabricated by hot embossing, which makes it flexible and cost‐efficient. Thin ZIF‐8 films are uniformly grown on the waveguides surface through a simple solution method, which is crucial for the envisioned production of metal organic framework‐based sensing devices on a large scale. Experimental results show that the produced optical elements exhibit a sensitivity of ≈2.5 μW/5 vol% toward carbon dioxide (CO2) with very rapid response time (≈6 s) and excellent reversibility of adsorption and desorption of the gas molecules. The demonstrated planar polymer sensing devices provide the potential to develop flexible on‐chip gas sensors in an inexpensive and reproducible way.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84701533","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}
V. Galstyan, N. Poli, V. Golovanov, A. D’arco, S. Macis, S. Lupi, E. Bolli, S. Kaciulis, A. Mezzi, E. Comini
Nowadays, there is a dramatically growing demand for nanocomposite materials with new functionalities for their application in chemical gas sensors and other catalytic devices. Moreover, green synthesis methods are intensively employed in the preparation of semiconductor nanostructures to reduce the hazardous effects on human health and the environment. Here the fabrication of a nanocomposite material based on WO3 and TiO2 (WO3/TiO2) with unusual electronic band alignment and novel gas sensing properties is reported. The material is synthesized by an eco‐friendly process based on the water vapor‐induced oxidation of tungsten/titanium metallic films. The pristine WO3 is highly sensitive to acetone, where the response of the material is enhanced by its operating temperature. Instead, WO3/TiO2 composite shows principally different sensing performance and it has a good selective response to carbon monoxide at a relatively low operating temperature. The obtained results indicate that the significant differences between the functionalities of pristine WO3 and WO3/TiO2 material can be attributed to the band alignment and the direction of charge transfer in the WO3/TiO2 heterojunction. Hence, an efficient way for the development of WO3/TiO2 nanocomposites, which can be useful for the engineering and optimization of gas sensing and catalytic properties of WO3, is presented.
{"title":"Tunable Chemical Reactivity and Selectivity of WO3/TiO2 Heterojunction for Gas Sensing Applications","authors":"V. Galstyan, N. Poli, V. Golovanov, A. D’arco, S. Macis, S. Lupi, E. Bolli, S. Kaciulis, A. Mezzi, E. Comini","doi":"10.1002/admt.202201751","DOIUrl":"https://doi.org/10.1002/admt.202201751","url":null,"abstract":"Nowadays, there is a dramatically growing demand for nanocomposite materials with new functionalities for their application in chemical gas sensors and other catalytic devices. Moreover, green synthesis methods are intensively employed in the preparation of semiconductor nanostructures to reduce the hazardous effects on human health and the environment. Here the fabrication of a nanocomposite material based on WO3 and TiO2 (WO3/TiO2) with unusual electronic band alignment and novel gas sensing properties is reported. The material is synthesized by an eco‐friendly process based on the water vapor‐induced oxidation of tungsten/titanium metallic films. The pristine WO3 is highly sensitive to acetone, where the response of the material is enhanced by its operating temperature. Instead, WO3/TiO2 composite shows principally different sensing performance and it has a good selective response to carbon monoxide at a relatively low operating temperature. The obtained results indicate that the significant differences between the functionalities of pristine WO3 and WO3/TiO2 material can be attributed to the band alignment and the direction of charge transfer in the WO3/TiO2 heterojunction. Hence, an efficient way for the development of WO3/TiO2 nanocomposites, which can be useful for the engineering and optimization of gas sensing and catalytic properties of WO3, is presented.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"1069 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77270295","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}
Amorphous oxide semiconductor thin‐film transistors (AOS TFTs) have shown significant potential in the applications of increasingly advanced transparent and flexible electronic devices, where high speed, high transparency, and low power consumption are highly demanded. Yet, typical back‐channel etch (BCE) configuration used in the majority of TFTs still suffers from poor gate controllability, severe electrical field dispersion, relatively large parasitic capacitance and contact resistance. Here, a new embedded structure for TFTs with self‐alignment and even simpler fabrication process, outperforming conventional BCE counterpart in above aspects, is proposed in this work. More concentrated electrical field, improved gate control ability accompanied with lower contact resistance are achieved in the embedded TFTs. Consequently, superior electrical characteristics with subthreshold swing of 106.7 mV dec−1 and mobility as high as 32.10 cm2 V−1 s−1 are obtained. In addition, leakage current as well as contact resistance evidently decline compared to that in traditional BCE TFTs. By the assistance of Silvaco TCAD simulation, the performance and mechanism behind are cross‐validated from another perspective. Overall, such embedded configuration has equipped TFTs with appealing performance and it is also possible to enable other devices exploiting such structure with new possibility and thus a broader application.
{"title":"Self‐Alignment Embedded Thin‐Film Transistor with High Transparency and Optimized Performance","authors":"Fei Zheng, Lei Li, Luodan Hu, Xiaoqing Huang, Tze-Peng Kuo, Kuan‐Chang Chang","doi":"10.1002/admt.202200879","DOIUrl":"https://doi.org/10.1002/admt.202200879","url":null,"abstract":"Amorphous oxide semiconductor thin‐film transistors (AOS TFTs) have shown significant potential in the applications of increasingly advanced transparent and flexible electronic devices, where high speed, high transparency, and low power consumption are highly demanded. Yet, typical back‐channel etch (BCE) configuration used in the majority of TFTs still suffers from poor gate controllability, severe electrical field dispersion, relatively large parasitic capacitance and contact resistance. Here, a new embedded structure for TFTs with self‐alignment and even simpler fabrication process, outperforming conventional BCE counterpart in above aspects, is proposed in this work. More concentrated electrical field, improved gate control ability accompanied with lower contact resistance are achieved in the embedded TFTs. Consequently, superior electrical characteristics with subthreshold swing of 106.7 mV dec−1 and mobility as high as 32.10 cm2 V−1 s−1 are obtained. In addition, leakage current as well as contact resistance evidently decline compared to that in traditional BCE TFTs. By the assistance of Silvaco TCAD simulation, the performance and mechanism behind are cross‐validated from another perspective. Overall, such embedded configuration has equipped TFTs with appealing performance and it is also possible to enable other devices exploiting such structure with new possibility and thus a broader application.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"174 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79630654","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}
Po-Yuen Ho, E. Dmitrieva, Ningwei Sun, O. Guskova, F. Lissel
Multilevel (or multistate) electrochromic devices have the potential to achieve highly compact memory capacity while instantaneously transferring data between memory and processing units. In this article, three novel solution‐processable ruthenium‐polymetallaynes (i.e., P1, P2, and P3), in which the redox‐addressable Ru center is covalently embedded into a conjugated organic polymer, are discussed. In pursuit of higher functionality (e.g., stable multistate behavior, low operating voltage), the organic ligand bridging the metal centers is systematically varied. The previously reported P1 has a bithiophene (BT) bridging ligand with a high degree of rotational freedom. By replacing BT with cyclopenta‐dithiophene in P2 and dithieno‐pyrrole (DTP) in P3, both of which are more planar than BT, the degree of freedom is decreased. By using DTP, redox‐matching is achieved between the metal center and organic ligand, leading to extra stability of the mixed‐valence (MV) state in P3. In‐depth experimental (i.e., in situ electron paramagnetic resonance and UV–vis–NIR spectroelectrochemistry) and theoretical studies (i.e., DFT calculations) are carried out on the polymer thin‐films, showing enhanced metal–metal (M–M) interaction in P2 and P3 and stable Robin–Day class III MV compound in P3. These polymers are also first time fabricated into solid‐state electrochromic devices and the stability of each oxidation state is characterized by tracing the change of transmittance over time, showing satisfactory cyclic stability and retention behavior (≈90% retention after 30 min).
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