We propose an inverse method to determine the material parameters of a transparent device without any knowledge of the corresponding transformation function. The required parameters are independently obtained and expr...We propose an inverse method to determine the material parameters of a transparent device without any knowledge of the corresponding transformation function. The required parameters are independently obtained and expressed as functions of the introduced generator. Moreover, to remove the inhomogeneity and anisotropy of material parameters, a layered transparent device composed of only homogeneous and isotropic materials is presented based on the effective medium theory. The feasibility of using the layered device in antenna protection is also investigated. Full-wave simulation is carried out for verification. This work paves a new way toward designing metamaterial devices without specifying the underlying coordinate transformation, and has great guiding significance for the practical fabrication of transparent devices.展开更多
Arbitrarily shaped electromagnetic transparent devices with homogeneous, non-negative, anisotropic and generic constitutive parameters are proposed based on linear transformation optics, which provides the flexibility...Arbitrarily shaped electromagnetic transparent devices with homogeneous, non-negative, anisotropic and generic constitutive parameters are proposed based on linear transformation optics, which provides the flexibility for device design that is applicable for the practical fabrication. To remove the anisotropic property, a layered structure is developed based on effective medium theory. Simulation results show that with sufficient layers, the performance of the layered transparent device is nearly as perfect as an ideal device, and it is able to protect an antenna without sacrificing its performance. The feasibility of designing a transparent device by using natural isotropic materials instead of metamaterials would dramatically reduce the difficulty of fabrication and further promote the practicality of the device.展开更多
Traditional technologies for manufacturing microfluidic devices often involve the use of molds for polydimethylsiloxane(PDMS)casting generated from photolithography techniques,which are time-consuming,costly,and diffi...Traditional technologies for manufacturing microfluidic devices often involve the use of molds for polydimethylsiloxane(PDMS)casting generated from photolithography techniques,which are time-consuming,costly,and difficult to use in generating multilayered structure.As an alternative,3D printing allows rapid and cost-effective prototyping and customization of complex microfluidic structures.However,3Dprinted devices are typically opaque and are challenging to create small channels.Herein,we introduce a novel“programmable optical window bonding”3D printing method that incorporates the bonding of an optical window during the printing process,facilitating the fabrication of transparent microfluidic devices with high printing fidelity.Our approach allows direct and rapid manufacturing of complex microfluidic structure without the use of molds for PDMS casting.We successfully demonstrated the applications of this method by fabricating a variety of microfluidic devices,including perfusable chips for cell culture,droplet generators for spheroid formation,and high-resolution droplet microfluidic devices involving different channel width and height for rapid antibiotic susceptibility testing.Overall,our 3D printing method demonstrates a rapid and cost-effective approach for manufacturing microfluidic devices,particularly in the biomedical field,where rapid prototyping and high-quality optical analysis are crucial.展开更多
Embedding a third and/or fourth component into a binary blend active layer of organic photovoltaics (OPVs) is a promising approach to achieve high-performance photovoltaic cells and modules. This multicomponent strate...Embedding a third and/or fourth component into a binary blend active layer of organic photovoltaics (OPVs) is a promising approach to achieve high-performance photovoltaic cells and modules. This multicomponent strategy favors absorption broadening via additional components. Quaternary OPV (QOPV) blends have four components in three possible configurations: (i) a donor and three acceptors, (ii) two donors and two acceptors, or (iii) three donors and an acceptor. Although quaternary systems have only been relatively recently studied compared to other systems in OPVs, leveraging the synergistic effects of the four components leads to record power conversion efficiencies, currently approaching 20%. QOPVs provide ample material choices for compatibility and channels for charge transfer mechanisms, possibly leading to optimized morphology and orientation. Reviewing recent progress in advancing QOPVs is essential for understanding their contribution to the OPV field. The review mainly discusses research progress in QOPVs with a keen interest in their various configurations, semitransparency, and outdoor and indoor applications. It describes the not-well-understood QOPV's general working mechanism. This review explores high-performance QOPVs based on the fourth component's contribution as a donor, acceptor, or dye molecule and beyond in photovoltaic applications. Finally, there is a discussion around QOPV's outlook and projected future research directions in this field. This review intends to provide an overview of the quaternary systems approach to OPVs and inform current and future researchers on investigating the full spectrum of OPVs.展开更多
Transparent photovoltaic devices(TPVDs)have attracted increasing attention in emerging electronic devices.As the application scenarios extend,there raise higher requirements regarding the stability and operating tempe...Transparent photovoltaic devices(TPVDs)have attracted increasing attention in emerging electronic devices.As the application scenarios extend,there raise higher requirements regarding the stability and operating temperature range of TPVDs.In this work,a unique preparation strategy is proposed for air stable TPVD with a wide operating temperature range,i.e.,a nanoscale architecture termed as H-TPVD is constructed that integrates a free-standing and highly transparent conductive hybrid film of graphene and single-walled carbon nanotubes(G-SWNT TCF for short)with a metal oxide NiO/TiO_(2)heterojunction.The preparation approach is suitable for scaling up.Thanks to the excellent transparent conductivity of the freestanding G-SWNT hybrid film and the ultrathin NiO/TiO_(2)heterojunction(100 nm),H-TPVD selectively absorbs the ultraviolet(UV)band of sunlight and has a transparency of up to 71%in the visible light.The integrated nanoscale architecture manifests the significant holecollecting capability of the G-SWNT hybrid film and the efficient carrier generation and separation within the ultrathin NiO/TiO_(2)heterojunction,resulting in excellent performance of the H-TPVD with a specific detectivity of 2.7×10^(10) Jones.Especially,the freestanding G-SWNT TCF is a super stable and non-porous two-dimensional film that can insulate gas molecules,thereby protecting the surface properties of NiO/TiO_(2)heterojunctions and enhancing the stability of H-TPVD.Having subjected to 20,000 cycles and storage in air for three months,the performance parameters such as photo-response signal,output power,and specific detectivity show no noticeable degradation.In particular,the as-fabricated self-powered H-TPVD can operate over a wide temperature range from −180 to 300℃,and can carry out solar-blind UV optical communication in this range.In addition,the 4×4 array H-TPVD demonstrates clear optical imaging.These results make it possible for H-TPVD to expand its potential application scenarios.展开更多
Fast and uniform growth of high-quality graphene on conventional glass is of great importance for practical applications of graphene glass. We report herein a confined-flow chemical vapor deposition （CVD） approach f...Fast and uniform growth of high-quality graphene on conventional glass is of great importance for practical applications of graphene glass. We report herein a confined-flow chemical vapor deposition （CVD） approach for the high- efficiency fabrication of graphene glass. The key feature of our approach is the fabrication of a 2-4 μm wide gap above the glass substrate, with plenty of stumbling blocks; this gap was found to significantly increase the collision probability of the carbon precursors and reactive fragments between one another and with the glass surface. As a result, the growth rate of graphene glass increased remarkably, together with an improvement in the growth quality and uniformity as compared to those in the conventional gas flow CVD technique. These high-quality graphene glasses exhibited an excellent defogging performance with much higher defogging speed and higher stability compared to those previously reported. The graphene sapphire glass was found to be an ideal substrate for growing uniform and ultra-smooth aluminum nitride thin films without the tedious pre-deposition of a buffer layer. The presented confined- flow CVD approach offers a simple and low-cost route for the mass production of graphene glass, which is believed to promote the practical applications of various graphene glasses.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61161007 and 61261002)the Natural Science Foundation of Yunnan Province,China(Grant No.2011FB018)+2 种基金the Postdoctoral Science Foundation of China(Grant No.2013M531989)the Key Program of Natural Science of Yunnan Province,China(Grant No.2013FA006)the Fostering Foundation for the Excellent Ph.D.Dissertation of Yunnan University,China
文摘We propose an inverse method to determine the material parameters of a transparent device without any knowledge of the corresponding transformation function. The required parameters are independently obtained and expressed as functions of the introduced generator. Moreover, to remove the inhomogeneity and anisotropy of material parameters, a layered transparent device composed of only homogeneous and isotropic materials is presented based on the effective medium theory. The feasibility of using the layered device in antenna protection is also investigated. Full-wave simulation is carried out for verification. This work paves a new way toward designing metamaterial devices without specifying the underlying coordinate transformation, and has great guiding significance for the practical fabrication of transparent devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61461052 and 11564044)the Key Program of the Natural Science Foundation of Yunnan Province,China(Grant Nos.2013FA006 and 2015FA015)
文摘Arbitrarily shaped electromagnetic transparent devices with homogeneous, non-negative, anisotropic and generic constitutive parameters are proposed based on linear transformation optics, which provides the flexibility for device design that is applicable for the practical fabrication. To remove the anisotropic property, a layered structure is developed based on effective medium theory. Simulation results show that with sufficient layers, the performance of the layered transparent device is nearly as perfect as an ideal device, and it is able to protect an antenna without sacrificing its performance. The feasibility of designing a transparent device by using natural isotropic materials instead of metamaterials would dramatically reduce the difficulty of fabrication and further promote the practicality of the device.
文摘Traditional technologies for manufacturing microfluidic devices often involve the use of molds for polydimethylsiloxane(PDMS)casting generated from photolithography techniques,which are time-consuming,costly,and difficult to use in generating multilayered structure.As an alternative,3D printing allows rapid and cost-effective prototyping and customization of complex microfluidic structures.However,3Dprinted devices are typically opaque and are challenging to create small channels.Herein,we introduce a novel“programmable optical window bonding”3D printing method that incorporates the bonding of an optical window during the printing process,facilitating the fabrication of transparent microfluidic devices with high printing fidelity.Our approach allows direct and rapid manufacturing of complex microfluidic structure without the use of molds for PDMS casting.We successfully demonstrated the applications of this method by fabricating a variety of microfluidic devices,including perfusable chips for cell culture,droplet generators for spheroid formation,and high-resolution droplet microfluidic devices involving different channel width and height for rapid antibiotic susceptibility testing.Overall,our 3D printing method demonstrates a rapid and cost-effective approach for manufacturing microfluidic devices,particularly in the biomedical field,where rapid prototyping and high-quality optical analysis are crucial.
基金the support of the research commission of the Catholic University of Lille and its Foundationthe IEMN laboratory for the financial supportsupport from the Materials Research Institute (MRI) and the Institute of Energy and the Environment (IEE) of the Pennsylvania State University。
文摘Embedding a third and/or fourth component into a binary blend active layer of organic photovoltaics (OPVs) is a promising approach to achieve high-performance photovoltaic cells and modules. This multicomponent strategy favors absorption broadening via additional components. Quaternary OPV (QOPV) blends have four components in three possible configurations: (i) a donor and three acceptors, (ii) two donors and two acceptors, or (iii) three donors and an acceptor. Although quaternary systems have only been relatively recently studied compared to other systems in OPVs, leveraging the synergistic effects of the four components leads to record power conversion efficiencies, currently approaching 20%. QOPVs provide ample material choices for compatibility and channels for charge transfer mechanisms, possibly leading to optimized morphology and orientation. Reviewing recent progress in advancing QOPVs is essential for understanding their contribution to the OPV field. The review mainly discusses research progress in QOPVs with a keen interest in their various configurations, semitransparency, and outdoor and indoor applications. It describes the not-well-understood QOPV's general working mechanism. This review explores high-performance QOPVs based on the fourth component's contribution as a donor, acceptor, or dye molecule and beyond in photovoltaic applications. Finally, there is a discussion around QOPV's outlook and projected future research directions in this field. This review intends to provide an overview of the quaternary systems approach to OPVs and inform current and future researchers on investigating the full spectrum of OPVs.
基金supported by the National Key Research and Development Program of China(Nos.2018YFA0208402 and 2020YFA0714700)the National Natural Science Foundation of China(Nos.52172060,51820105002,11634014,and 51372269)X.J.W.thanks Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020005).
文摘Transparent photovoltaic devices(TPVDs)have attracted increasing attention in emerging electronic devices.As the application scenarios extend,there raise higher requirements regarding the stability and operating temperature range of TPVDs.In this work,a unique preparation strategy is proposed for air stable TPVD with a wide operating temperature range,i.e.,a nanoscale architecture termed as H-TPVD is constructed that integrates a free-standing and highly transparent conductive hybrid film of graphene and single-walled carbon nanotubes(G-SWNT TCF for short)with a metal oxide NiO/TiO_(2)heterojunction.The preparation approach is suitable for scaling up.Thanks to the excellent transparent conductivity of the freestanding G-SWNT hybrid film and the ultrathin NiO/TiO_(2)heterojunction(100 nm),H-TPVD selectively absorbs the ultraviolet(UV)band of sunlight and has a transparency of up to 71%in the visible light.The integrated nanoscale architecture manifests the significant holecollecting capability of the G-SWNT hybrid film and the efficient carrier generation and separation within the ultrathin NiO/TiO_(2)heterojunction,resulting in excellent performance of the H-TPVD with a specific detectivity of 2.7×10^(10) Jones.Especially,the freestanding G-SWNT TCF is a super stable and non-porous two-dimensional film that can insulate gas molecules,thereby protecting the surface properties of NiO/TiO_(2)heterojunctions and enhancing the stability of H-TPVD.Having subjected to 20,000 cycles and storage in air for three months,the performance parameters such as photo-response signal,output power,and specific detectivity show no noticeable degradation.In particular,the as-fabricated self-powered H-TPVD can operate over a wide temperature range from −180 to 300℃,and can carry out solar-blind UV optical communication in this range.In addition,the 4×4 array H-TPVD demonstrates clear optical imaging.These results make it possible for H-TPVD to expand its potential application scenarios.
基金This work was financially supported by the National Basic Research Program of China （Nos. 2016YFA0200103, 2013CB932603, 2012CB933404, and 2013CB934600）, the National Natural Science Foundation of China （Nos. 51520105003 and 51432002）, the Ministry of Education （No. 20120001130010）, and the Beijing Municipal Science and Technology Planning Project （No. Z151100003315013）.
文摘Fast and uniform growth of high-quality graphene on conventional glass is of great importance for practical applications of graphene glass. We report herein a confined-flow chemical vapor deposition （CVD） approach for the high- efficiency fabrication of graphene glass. The key feature of our approach is the fabrication of a 2-4 μm wide gap above the glass substrate, with plenty of stumbling blocks; this gap was found to significantly increase the collision probability of the carbon precursors and reactive fragments between one another and with the glass surface. As a result, the growth rate of graphene glass increased remarkably, together with an improvement in the growth quality and uniformity as compared to those in the conventional gas flow CVD technique. These high-quality graphene glasses exhibited an excellent defogging performance with much higher defogging speed and higher stability compared to those previously reported. The graphene sapphire glass was found to be an ideal substrate for growing uniform and ultra-smooth aluminum nitride thin films without the tedious pre-deposition of a buffer layer. The presented confined- flow CVD approach offers a simple and low-cost route for the mass production of graphene glass, which is believed to promote the practical applications of various graphene glasses.
