G. K. K. Chik, Na Xiao, Xudong Ji, A. Tsang, G. Leung, Shiming Zhang, C. Tin, P. Chan
Miniaturization and minimization of mechanical mismatch in neural probes have been two well‐proven directions in suppressing immune response and improving spatial resolution for neuronal stimulations and recordings. While the high impedance brought by the miniaturization of electrodes has been addressed by using conductive polymers coatings in multiple reports, the stiffness of such coatings remains orders of magnitude higher than that of the brain tissue. Here, a flat neural probe based on a highly flexible microelectrode array with electrodeposited hydrogel coatings poly(2‐hydroxyethyl methacrylate) (pHEMA) and conductive polymer poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS), with a cross‐section area at only 300 µm × 2.5 µm is presented. The PEDOT/PSS coating provides a low interfacial impedance, and the pHEMA deposition bridges the mechanical mismatch between the probe and the brain tissues. The two layers of polymers modification enhance the signal‐to‐noise ratio and allow the microelectrodes array to be engineered for both recording and stimulation purposes. Besides, in vivo testing of microelectrode arrays implanted in rat hippocampus confirms a high senstivity in neural signal recording and excellent charge injection capacity which can induce long‐term potentiation in neural activities in the hippocampus. The probes provide a robust and low‐cost solution to the brain interfaces problem.
神经探针中机械失配的小型化和最小化已经被证明是抑制免疫反应和提高神经元刺激和记录的空间分辨率的两个很好的方向。虽然在多个报告中已经通过使用导电聚合物涂层解决了电极小型化带来的高阻抗问题，但这种涂层的硬度仍然比脑组织的硬度高几个数量级。本文提出了一种基于高柔性微电极阵列的平面神经探针，该微电极阵列具有电沉积的水凝胶涂层聚(2‐甲基丙烯酸羟乙酯)(pHEMA)和导电聚合物聚(3,4‐乙烯二氧噻吩)聚苯乙烯磺酸盐(PEDOT/PSS)，其横截面面积仅为300 μ m × 2.5 μ m。PEDOT/PSS涂层提供了低界面阻抗，pHEMA沉积弥补了探针和脑组织之间的机械不匹配。两层聚合物修饰提高了信噪比，并允许微电极阵列用于记录和刺激目的。此外，植入大鼠海马的微电极阵列的体内实验证实，微电极阵列具有高灵敏度的神经信号记录和良好的电荷注入能力，可以诱导海马神经活动的长时程增强。该探针为脑接口问题提供了一种强大且低成本的解决方案。
{"title":"Flexible Multichannel Neural Probe Developed by Electropolymerization for Localized Stimulation and Sensing","authors":"G. K. K. Chik, Na Xiao, Xudong Ji, A. Tsang, G. Leung, Shiming Zhang, C. Tin, P. Chan","doi":"10.1002/admt.202200143","DOIUrl":"https://doi.org/10.1002/admt.202200143","url":null,"abstract":"Miniaturization and minimization of mechanical mismatch in neural probes have been two well‐proven directions in suppressing immune response and improving spatial resolution for neuronal stimulations and recordings. While the high impedance brought by the miniaturization of electrodes has been addressed by using conductive polymers coatings in multiple reports, the stiffness of such coatings remains orders of magnitude higher than that of the brain tissue. Here, a flat neural probe based on a highly flexible microelectrode array with electrodeposited hydrogel coatings poly(2‐hydroxyethyl methacrylate) (pHEMA) and conductive polymer poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS), with a cross‐section area at only 300 µm × 2.5 µm is presented. The PEDOT/PSS coating provides a low interfacial impedance, and the pHEMA deposition bridges the mechanical mismatch between the probe and the brain tissues. The two layers of polymers modification enhance the signal‐to‐noise ratio and allow the microelectrodes array to be engineered for both recording and stimulation purposes. Besides, in vivo testing of microelectrode arrays implanted in rat hippocampus confirms a high senstivity in neural signal recording and excellent charge injection capacity which can induce long‐term potentiation in neural activities in the hippocampus. The probes provide a robust and low‐cost solution to the brain interfaces problem.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"07 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86022269","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}
Adrian T. Nash, Daniel A. N. Foster, Shyan Thompson, Seung-Su Han, Madison K. Fernandez, D. K. Hwang
Hydrogel‐based biosensing, based on antigen–antibody binding, has been utilized for various biomedical applications such as cancer monitoring. Hydrogels offer highly sensitive detection with the prevention of nonspecific binding because of 3D porous structure and hydrophilicity. However, these hydrogel‐based biosensing platforms require a time scale of hours to complete immunoassays because binding events are diffusion‐limited, where target biomolecules must diffuse into and throughout the 3D porous network. Here, a new rapid microfluidic platform is introduced utilizing a cross‐flow induced advective‐transportation of targets into a hydrogel membrane with fluorescent reporting. This flow enhanced delivery of target analytes significantly reduces their detection time to under 15 min. This flow effect is also numerically investigated on the detection process. Both numerical and experimental results show an exponential decrease in the detection time. More importantly, the cross‐flow configuration in our platform provides an additional size‐based filtration feature that effectively selects against larger components in a blood sample, such as red blood cells, during the detection process. This addition, not seen in conventional biosensing platforms, eliminates the need for blood sample prefiltration.
{"title":"A New Rapid Microfluidic Detection Platform Utilizing Hydrogel‐Membrane under Cross‐Flow","authors":"Adrian T. Nash, Daniel A. N. Foster, Shyan Thompson, Seung-Su Han, Madison K. Fernandez, D. K. Hwang","doi":"10.1002/admt.202101396","DOIUrl":"https://doi.org/10.1002/admt.202101396","url":null,"abstract":"Hydrogel‐based biosensing, based on antigen–antibody binding, has been utilized for various biomedical applications such as cancer monitoring. Hydrogels offer highly sensitive detection with the prevention of nonspecific binding because of 3D porous structure and hydrophilicity. However, these hydrogel‐based biosensing platforms require a time scale of hours to complete immunoassays because binding events are diffusion‐limited, where target biomolecules must diffuse into and throughout the 3D porous network. Here, a new rapid microfluidic platform is introduced utilizing a cross‐flow induced advective‐transportation of targets into a hydrogel membrane with fluorescent reporting. This flow enhanced delivery of target analytes significantly reduces their detection time to under 15 min. This flow effect is also numerically investigated on the detection process. Both numerical and experimental results show an exponential decrease in the detection time. More importantly, the cross‐flow configuration in our platform provides an additional size‐based filtration feature that effectively selects against larger components in a blood sample, such as red blood cells, during the detection process. This addition, not seen in conventional biosensing platforms, eliminates the need for blood sample prefiltration.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90153881","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}
Chao Ma, Meng Wang, Pierre Claver Uzabakiriho, G. Zhao
With the rapid advances in wearable technology, several excellent strain sensors have been developed. Recent strain sensors have met various requirements, such as mechanical applicability, rapid responsiveness, and high sensitivity. Nevertheless, the processing technology, wearing comfort, and safety of strain sensors, which have received inadequate attention, have greatly hindered their commercial development and large‐scale use. Through mature electrospinning and screen‐printing, a high‐performance, safe, comfortable, waterproof, breathable, economical, and reliable wearable strain sensor is simply and quickly prepared. This strain sensor has excellent repeatability and stability with remarkable sensitivity (maximum gauge factor = 520), a broad working strain range (500%), and an ultrafast response time (100 ms). Notably, the mechanical properties of the proposed strain sensor are similar to those of natural skin, making the sensor a good match to the skin. Additionally, the strain sensor has incomparable biofriendly, enabling long‐term harmless contact with the skin. To the best of the authors’ knowledge, this is the first report on the optimization of flexible electronic equipment in terms of the manufacturing process, sensing performance, and wearing experience. The results of this study have important implications for the development and practical application of flexible electronics.
{"title":"High Sensitivity, Broad Working Range, Comfortable, and Biofriendly Wearable Strain Sensor for Electronic Skin","authors":"Chao Ma, Meng Wang, Pierre Claver Uzabakiriho, G. Zhao","doi":"10.1002/admt.202200106","DOIUrl":"https://doi.org/10.1002/admt.202200106","url":null,"abstract":"With the rapid advances in wearable technology, several excellent strain sensors have been developed. Recent strain sensors have met various requirements, such as mechanical applicability, rapid responsiveness, and high sensitivity. Nevertheless, the processing technology, wearing comfort, and safety of strain sensors, which have received inadequate attention, have greatly hindered their commercial development and large‐scale use. Through mature electrospinning and screen‐printing, a high‐performance, safe, comfortable, waterproof, breathable, economical, and reliable wearable strain sensor is simply and quickly prepared. This strain sensor has excellent repeatability and stability with remarkable sensitivity (maximum gauge factor = 520), a broad working strain range (500%), and an ultrafast response time (100 ms). Notably, the mechanical properties of the proposed strain sensor are similar to those of natural skin, making the sensor a good match to the skin. Additionally, the strain sensor has incomparable biofriendly, enabling long‐term harmless contact with the skin. To the best of the authors’ knowledge, this is the first report on the optimization of flexible electronic equipment in terms of the manufacturing process, sensing performance, and wearing experience. The results of this study have important implications for the development and practical application of flexible electronics.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86019429","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}
Elaborate engineering of emitting wavelength of green down‐converter in the spectral range of ≈525–535 nm with narrow full‐width at half‐maximum (fwhm < 25 nm) is an essential prerequisite for faithfully reproducing colors in the quantum dot (QD)‐based backlit display. Herein, different from the previous complex synthesis for green films, FAPbBr3 perovskite QDs films are fabricated by a dual‐additive assisted in situ growth strategy. Both C6H5CH2CH2NH3+ and 1,4,7,10,13,16‐hexaoxacyclooctadecane additives are introduced to synergistically tune green emitting (≈525–535 nm) with the narrowest fwhm down to 21 nm and the highest photoluminescence quantum yield (PLQY) up to 99%. Improved nanocomposite film with excellent long‐term stability is used to construct a prototype liquid crystal display (LCD) with a wide color gamut (118% National Television System Committee and 88% Recommendation BT 2020), a high saturation, and a remarkable color rendition. The performance is superior to that of the commercial white‐LED‐based LCD, showing a great potential of the present green film for high‐definition display application in the future.
{"title":"In Situ Growth of Ultrapure Green‐Emitting FAPbBr3‐PVDF Films via a Synergetic Dual‐Additive Strategy for Wide Color Gamut Backlit Display","authors":"Changbin Yang, Weifan Niu, Renjing Chen, T. Pang, Jidong Lin, Yongping Zheng, Ruidan Zhang, Zhibin Wang, Ping Huang, Feng Huang, Daqin Chen","doi":"10.1002/admt.202200100","DOIUrl":"https://doi.org/10.1002/admt.202200100","url":null,"abstract":"Elaborate engineering of emitting wavelength of green down‐converter in the spectral range of ≈525–535 nm with narrow full‐width at half‐maximum (fwhm < 25 nm) is an essential prerequisite for faithfully reproducing colors in the quantum dot (QD)‐based backlit display. Herein, different from the previous complex synthesis for green films, FAPbBr3 perovskite QDs films are fabricated by a dual‐additive assisted in situ growth strategy. Both C6H5CH2CH2NH3+ and 1,4,7,10,13,16‐hexaoxacyclooctadecane additives are introduced to synergistically tune green emitting (≈525–535 nm) with the narrowest fwhm down to 21 nm and the highest photoluminescence quantum yield (PLQY) up to 99%. Improved nanocomposite film with excellent long‐term stability is used to construct a prototype liquid crystal display (LCD) with a wide color gamut (118% National Television System Committee and 88% Recommendation BT 2020), a high saturation, and a remarkable color rendition. The performance is superior to that of the commercial white‐LED‐based LCD, showing a great potential of the present green film for high‐definition display application in the future.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86233558","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}
Tuo Zhang, Cuicui Ling, Xiaomeng Wang, B. Feng, Min Cao, Xin Xue, Q. Xue, Jianqiang Zhang, Lei Zhu, Chuanke Wang, Haipeng Lu, Wenpeng Liu
The flexible photodetector plays an important role in improving human medical health status. However, the narrow spectral detection range, poor stress stability, and non‐degradation of traditional flexible photodetectors greatly hinder the further development of wearable medical devices. In this paper, a novel flexible infrared photodetector is proposed for intelligent healthcare monitoring using high purity lead sulfide (PbS) nanoparticles on paper‐based flexible substrate synthesized by hydrothermal method and physical friction. The excellent performance of the detector is attributed to the 1.01 eV band gap and six‐arm stellate dendritic structure of PdS, a good combination between PbS and paper substrate via physical friction. As a result, our photodetector demonstrates wide‐spectrum detection capabilities from 365 to 1550 nm. The photodetector at 980 nm (50.4 μW cm−2) shows responsivity of 6.45 mA W−1, detectivity of 6.4 × 1010 Jones, response recovery time of 0.36 s/0.41 s, with good mechanical stability. By comparison, our detector has a wider detection range, better weak signal detection performance, and shorter response time than the performance of the former paper‐based detector. Furthermore, the paper‐based PbS photodetector as a dual‐wavelength photoplethysmography sensor is applied to analyze the oxygen saturation and develop an intelligent bandage to monitor wound healing. This paper‐based PbS photodetector has tremendous potential in the field of wearable medical devices and intelligent medical applications are expected.
{"title":"Six‐arm Stellat Dendritic‐PbS Flexible Infrared Photodetector for Intelligent Healthcare Monitoring","authors":"Tuo Zhang, Cuicui Ling, Xiaomeng Wang, B. Feng, Min Cao, Xin Xue, Q. Xue, Jianqiang Zhang, Lei Zhu, Chuanke Wang, Haipeng Lu, Wenpeng Liu","doi":"10.1002/admt.202200250","DOIUrl":"https://doi.org/10.1002/admt.202200250","url":null,"abstract":"The flexible photodetector plays an important role in improving human medical health status. However, the narrow spectral detection range, poor stress stability, and non‐degradation of traditional flexible photodetectors greatly hinder the further development of wearable medical devices. In this paper, a novel flexible infrared photodetector is proposed for intelligent healthcare monitoring using high purity lead sulfide (PbS) nanoparticles on paper‐based flexible substrate synthesized by hydrothermal method and physical friction. The excellent performance of the detector is attributed to the 1.01 eV band gap and six‐arm stellate dendritic structure of PdS, a good combination between PbS and paper substrate via physical friction. As a result, our photodetector demonstrates wide‐spectrum detection capabilities from 365 to 1550 nm. The photodetector at 980 nm (50.4 μW cm−2) shows responsivity of 6.45 mA W−1, detectivity of 6.4 × 1010 Jones, response recovery time of 0.36 s/0.41 s, with good mechanical stability. By comparison, our detector has a wider detection range, better weak signal detection performance, and shorter response time than the performance of the former paper‐based detector. Furthermore, the paper‐based PbS photodetector as a dual‐wavelength photoplethysmography sensor is applied to analyze the oxygen saturation and develop an intelligent bandage to monitor wound healing. This paper‐based PbS photodetector has tremendous potential in the field of wearable medical devices and intelligent medical applications are expected.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81396350","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}
In this paper, a novel multimode waveguide implemented on a silicon‐on‐insulator (SOI) platform that supports several transverse (TE)/transverse magnetic (TM) modes across a broad range of wavelengths is experimentally demonstrated. The fully etched metamaterial design combines a gradient curvature bend with trapezoidal subwavelength grating segments and tapered concentric bridging strips. The simulations showed successful propagation of up to nine modes (5 TE and 4 TM) on the 340 nm SOI platform, with excess losses below 2.4 dB, and intermodal cross‐talk of less than −15.7 dB. Experimentally, a compact multimode bend with a radius of 10 µm on a 220 nm SOI platform is demonstrated that successfully supports four TE modes, with average signal‐to‐cross‐talk extinction ratio levels of 14.4 dB or better, across a wavelength band of 1500–1600 nm. This versatile multimode waveguide bend can be employed as a fundamental building block for densely integrated photonic circuits and mode multiplexing systems.
{"title":"Subwavelength Grating Metamaterial Multimode Bend for Silicon Waveguides","authors":"Kevan K. MacKay, Shurui Wang, P. Cheben, W. Ye","doi":"10.1002/admt.202200038","DOIUrl":"https://doi.org/10.1002/admt.202200038","url":null,"abstract":"In this paper, a novel multimode waveguide implemented on a silicon‐on‐insulator (SOI) platform that supports several transverse (TE)/transverse magnetic (TM) modes across a broad range of wavelengths is experimentally demonstrated. The fully etched metamaterial design combines a gradient curvature bend with trapezoidal subwavelength grating segments and tapered concentric bridging strips. The simulations showed successful propagation of up to nine modes (5 TE and 4 TM) on the 340 nm SOI platform, with excess losses below 2.4 dB, and intermodal cross‐talk of less than −15.7 dB. Experimentally, a compact multimode bend with a radius of 10 µm on a 220 nm SOI platform is demonstrated that successfully supports four TE modes, with average signal‐to‐cross‐talk extinction ratio levels of 14.4 dB or better, across a wavelength band of 1500–1600 nm. This versatile multimode waveguide bend can be employed as a fundamental building block for densely integrated photonic circuits and mode multiplexing systems.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84221690","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}
A light converter system with high light sensitivity that could sense the near‐infrared (NIR) signal is one of the prerequisites for the whole Internet of Things (IoT) field. Here, a NIR to visible light converter (NVLC) which could emit visible light according to external NIR is reported. The NVLC is an integration of an inverted perovskite quantum dot light emitting diodes and a hybrid lead sulfide quantum dots/graphene transistor. The latter acts as a photodetector to convert NIR signals into electrical signals, and the former emits visible light with an intensity controlled by the electrical signals. The luminous intensity of the device, which emits green light with a peak of 520 nm, is positively correlated with the intensity of the NIR. Further, the micron‐scale NVLCs are integrated into a matrix device that could sense NIR image and display it into visible light image. The NVLC with sensing, converting NIR to visible light is believed to have various promising applications in the IoT field.
{"title":"Near‐Infrared to Visible Light Converter by Integrating Graphene Transistor into Perovskite Quantum Dot Light Emitting Diodes","authors":"Wei Zhao, Sheng Bi, Chengming Jiang, Jinhui Song","doi":"10.1002/admt.202200043","DOIUrl":"https://doi.org/10.1002/admt.202200043","url":null,"abstract":"A light converter system with high light sensitivity that could sense the near‐infrared (NIR) signal is one of the prerequisites for the whole Internet of Things (IoT) field. Here, a NIR to visible light converter (NVLC) which could emit visible light according to external NIR is reported. The NVLC is an integration of an inverted perovskite quantum dot light emitting diodes and a hybrid lead sulfide quantum dots/graphene transistor. The latter acts as a photodetector to convert NIR signals into electrical signals, and the former emits visible light with an intensity controlled by the electrical signals. The luminous intensity of the device, which emits green light with a peak of 520 nm, is positively correlated with the intensity of the NIR. Further, the micron‐scale NVLCs are integrated into a matrix device that could sense NIR image and display it into visible light image. The NVLC with sensing, converting NIR to visible light is believed to have various promising applications in the IoT field.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"193 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74819683","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}
Sébastien Uzel, Robert D. Weeks, Michael Eriksson, Dimitri Kokkinis, J. Lewis
Direct ink writing is a facile method that enables biological, structural, and functional materials to be printed in three dimensions (3D). To date, this extrusion‐based method has primarily been used to soft materials in a layer‐wise manner on planar substrates. However, many emerging applications would benefit from the ability to conformally print materials of varying composition on substrates with arbitrary topography. Here, a high throughput platform based on multimaterial multinozzle adaptive 3D printing (MMA‐3DP) that provides independent control of nozzle height and seamless switching between inks is reported. To demonstrate the MMA‐3DP platform, conformally pattern viscoelastic inks composed of triblock copolymer, gelatin, and photopolymerizable polyacrylate materials onto complex substrates of varying topography, including those with surface defects that mimic skin abrasions or deep gouges. This platform opens new avenues for rapidly patterning soft materials for structural, functional, and biomedical applications.
{"title":"Multimaterial Multinozzle Adaptive 3D Printing of Soft Materials","authors":"Sébastien Uzel, Robert D. Weeks, Michael Eriksson, Dimitri Kokkinis, J. Lewis","doi":"10.1002/admt.202101710","DOIUrl":"https://doi.org/10.1002/admt.202101710","url":null,"abstract":"Direct ink writing is a facile method that enables biological, structural, and functional materials to be printed in three dimensions (3D). To date, this extrusion‐based method has primarily been used to soft materials in a layer‐wise manner on planar substrates. However, many emerging applications would benefit from the ability to conformally print materials of varying composition on substrates with arbitrary topography. Here, a high throughput platform based on multimaterial multinozzle adaptive 3D printing (MMA‐3DP) that provides independent control of nozzle height and seamless switching between inks is reported. To demonstrate the MMA‐3DP platform, conformally pattern viscoelastic inks composed of triblock copolymer, gelatin, and photopolymerizable polyacrylate materials onto complex substrates of varying topography, including those with surface defects that mimic skin abrasions or deep gouges. This platform opens new avenues for rapidly patterning soft materials for structural, functional, and biomedical applications.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"63 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90139575","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}
Lingying Li, Wanli Li, Xuying Liu, Mizuki Tenjimbayashi, H. Segawa, C. Niikura, T. Nakayama, T. Minari
Flexible transparent conductors (TCs) are the fundamental components for emerging soft optoelectronics because of their excellent optical, electrical, and mechanical properties. These properties are attributed to reasonable alignment of conductive functional nanomaterials, especially 1D inorganic nanowires. Although various patterning technologies are proposed, patterning highly transparent conductors with satisfactory conductivity and flexibility in a facile, scalable, and versatile manner remains an open issue. Here, a directed self‐assembly strategy is presented for patterning silver nanowires (AgNWs) into flexible TCs with a cross‐linked network structure using microflow velocity‐field‐induced alignment at a liquid–solid interface. Under dual‐surface architectonics, the periodically varying internal microflow in the overcoated AgNW suspension facilitates the spontaneous alignment of the AgNWs on the designated regions in a layer‐by‐layer manner, yielding highly ordered AgNW TCs with an ultrahigh transmittance (98.2%), low sheet resistance (29.7 Ω sq−1), and prominent mechanical deformability. The proposed strategy is further applied to fabricate high‐accuracy arbitrary AgNW circuits to realize flexible transparent heaters with adjustable localized heat sources. This is a universal and customizable method for producing functional nanomaterials with hardly any scale or shape limitations in a streamlined fashion and provides great freedom for prototyping and manufacturing high‐performance soft optoelectronics.
{"title":"Microflow Manipulation by Velocity Field Gradient: Spontaneous Patterning of Silver Nanowires for Tailored Flexible Transparent Conductors","authors":"Lingying Li, Wanli Li, Xuying Liu, Mizuki Tenjimbayashi, H. Segawa, C. Niikura, T. Nakayama, T. Minari","doi":"10.1002/admt.202101687","DOIUrl":"https://doi.org/10.1002/admt.202101687","url":null,"abstract":"Flexible transparent conductors (TCs) are the fundamental components for emerging soft optoelectronics because of their excellent optical, electrical, and mechanical properties. These properties are attributed to reasonable alignment of conductive functional nanomaterials, especially 1D inorganic nanowires. Although various patterning technologies are proposed, patterning highly transparent conductors with satisfactory conductivity and flexibility in a facile, scalable, and versatile manner remains an open issue. Here, a directed self‐assembly strategy is presented for patterning silver nanowires (AgNWs) into flexible TCs with a cross‐linked network structure using microflow velocity‐field‐induced alignment at a liquid–solid interface. Under dual‐surface architectonics, the periodically varying internal microflow in the overcoated AgNW suspension facilitates the spontaneous alignment of the AgNWs on the designated regions in a layer‐by‐layer manner, yielding highly ordered AgNW TCs with an ultrahigh transmittance (98.2%), low sheet resistance (29.7 Ω sq−1), and prominent mechanical deformability. The proposed strategy is further applied to fabricate high‐accuracy arbitrary AgNW circuits to realize flexible transparent heaters with adjustable localized heat sources. This is a universal and customizable method for producing functional nanomaterials with hardly any scale or shape limitations in a streamlined fashion and provides great freedom for prototyping and manufacturing high‐performance soft optoelectronics.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75451394","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}
AlGaN‐based deep ultraviolet light‐emitting diodes (UV LEDs) have gained rapidly growing attention due to their wide applications in water purification, air disinfection, and sensing as well as optical communication. Moreover, deep UV radiation has been verified as one of effective way to inactivate COVID‐19. However, although numerous efforts have been made in deep UV LED chips, the reported highest external quantum efficiency (EQE) of them is 20.3%, which is far lower than that of visible LEDs. The EQE of commercial packaged AlGaN‐based deep UV LEDs is usually lower than 5%, which will cause serious reliability problems as well. Therefore, it is very urgent to improve EQE and reliability of the devices from packaging level. In this review, a systematical summarization about the packaging technologies of AlGaN‐based deep UV LEDs has been analyzed and future prospects have been made as well. Firstly, this work provides a brief overview of the devices and analyzes why the packaging level reduces EQE and reliability in theory. Then, systematically reviews the recent advances in packaging technologies and deep UV micro‐LEDs. Finally, conclusions and outlooks are given as well. This review is of great significance for promoting the development of the packaging technologies for AlGaN‐based deep UV LEDs.
{"title":"Recent Advances in Packaging Technologies of AlGaN‐Based Deep Ultraviolet Light‐Emitting Diodes","authors":"Shenghua Liang, Wenhong Sun","doi":"10.1002/admt.202101502","DOIUrl":"https://doi.org/10.1002/admt.202101502","url":null,"abstract":"AlGaN‐based deep ultraviolet light‐emitting diodes (UV LEDs) have gained rapidly growing attention due to their wide applications in water purification, air disinfection, and sensing as well as optical communication. Moreover, deep UV radiation has been verified as one of effective way to inactivate COVID‐19. However, although numerous efforts have been made in deep UV LED chips, the reported highest external quantum efficiency (EQE) of them is 20.3%, which is far lower than that of visible LEDs. The EQE of commercial packaged AlGaN‐based deep UV LEDs is usually lower than 5%, which will cause serious reliability problems as well. Therefore, it is very urgent to improve EQE and reliability of the devices from packaging level. In this review, a systematical summarization about the packaging technologies of AlGaN‐based deep UV LEDs has been analyzed and future prospects have been made as well. Firstly, this work provides a brief overview of the devices and analyzes why the packaging level reduces EQE and reliability in theory. Then, systematically reviews the recent advances in packaging technologies and deep UV micro‐LEDs. Finally, conclusions and outlooks are given as well. This review is of great significance for promoting the development of the packaging technologies for AlGaN‐based deep UV LEDs.","PeriodicalId":7200,"journal":{"name":"Advanced Materials & Technologies","volume":"91 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83957019","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}
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