Motivated by a greater need for increased performance in modern-day technology, this paper shows the results of theoretical calculations for the optical properties of Al/SiO2 nano-layered metamaterial with hyperbolic dispersion. Our main focus is on designing a metamaterial with low losses, since losses might outweigh any increase in speed of photonic devices. We have investigated the effect of three major variables (number/thickness of the Al layers and Al fill fraction) on inherent losses and hyperbolic dispersion using the effective medium approximation with non-local corrections. Our model predicts a variation of the dielectric permittivity only in the perpendicular direction as the number of Al layers changes. First, we present the results of the detailed study of varying the number of Al layers, N, in attempt to find the “saturation limit” of non-local corrections in Al/SiO2 layers. Next, we changed Al fill fraction in a sample of N= 20 layers to find parameters for the material with minimized losses. We found that both of these effects determine the transition wavelength to hyperbolic dispersion, which allows for fine-tuning of the optical properties for future applications.
{"title":"Theoretical design of nano-layered Al/SiO2 metamaterial with hyperbolic dispersion with minimum losses","authors":"P. Kelly, D. White, L. Kuznetsova","doi":"10.1117/12.2187137","DOIUrl":"https://doi.org/10.1117/12.2187137","url":null,"abstract":"Motivated by a greater need for increased performance in modern-day technology, this paper shows the results of theoretical calculations for the optical properties of Al/SiO2 nano-layered metamaterial with hyperbolic dispersion. Our main focus is on designing a metamaterial with low losses, since losses might outweigh any increase in speed of photonic devices. We have investigated the effect of three major variables (number/thickness of the Al layers and Al fill fraction) on inherent losses and hyperbolic dispersion using the effective medium approximation with non-local corrections. Our model predicts a variation of the dielectric permittivity only in the perpendicular direction as the number of Al layers changes. First, we present the results of the detailed study of varying the number of Al layers, N, in attempt to find the “saturation limit” of non-local corrections in Al/SiO2 layers. Next, we changed Al fill fraction in a sample of N= 20 layers to find parameters for the material with minimized losses. We found that both of these effects determine the transition wavelength to hyperbolic dispersion, which allows for fine-tuning of the optical properties for future applications.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132087760","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}
AgInS2-ZnS (ZAIS) quaternary semiconductors nanocrystals are versatile cadmium-free luminescent nanomaterials. Their broad emission spectrum and strong absorption make them ideal for the development of new white-LED devices taking advantage of nano-optical phenomena. We recently found strategies to increase the photoluminescence quantum yield of ZAIS nanocrystals up to 80%. In a second step toward high efficiency luminescent materials, we aim at increasing the net conversion efficiency of ZAIS nanocrystals by coupling them with metallic nano-antennae. Indeed, by grafting ZAIS nanocrystals onto carefully chosen metal/dielectric core/shell nanoparticles, both the absorption and emission processes can be tuned and enhanced. A finite-element simulation based on the discrete dipole approximation (DDA) was used to predict the nano-optical behavior of silver@oxide@ZAIS nanostructures. Desirable combinations of materials and geometry for the antennae were identified. A chemical method for the synthesis of the simulated nanostructures was developed. The coupling of ZAIS nanocrystals emission with the plasmonic structure is experimentally observed and is in accordance with our predictions.
{"title":"Design of metal/dielectric/nanocrystals core/shell/shell nano-structures for the fluorescence enhancement of cadmium-free semiconductor nanocrystals","authors":"T. Chevallier, G. Le Blevennec, F. Chandezon","doi":"10.1117/12.2186529","DOIUrl":"https://doi.org/10.1117/12.2186529","url":null,"abstract":"AgInS2-ZnS (ZAIS) quaternary semiconductors nanocrystals are versatile cadmium-free luminescent nanomaterials. Their broad emission spectrum and strong absorption make them ideal for the development of new white-LED devices taking advantage of nano-optical phenomena. We recently found strategies to increase the photoluminescence quantum yield of ZAIS nanocrystals up to 80%. In a second step toward high efficiency luminescent materials, we aim at increasing the net conversion efficiency of ZAIS nanocrystals by coupling them with metallic nano-antennae. Indeed, by grafting ZAIS nanocrystals onto carefully chosen metal/dielectric core/shell nanoparticles, both the absorption and emission processes can be tuned and enhanced. A finite-element simulation based on the discrete dipole approximation (DDA) was used to predict the nano-optical behavior of silver@oxide@ZAIS nanostructures. Desirable combinations of materials and geometry for the antennae were identified. A chemical method for the synthesis of the simulated nanostructures was developed. The coupling of ZAIS nanocrystals emission with the plasmonic structure is experimentally observed and is in accordance with our predictions.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131217194","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}
Porous silica nanoparticles are considering good systems for drug cargo and liquid separation. In this work we studied the release of rhodamine 6G (Rh6G) from solid and porous silica nanoparticles. Solid and porous SiO2 spheres were prepared by sol-gel method. Nanoporous channels were produced by using a surfactant that was removed by chemical procedure. Rh6G was incorporated into the channels by impregnation. The hexagonal structure of the pores was detected by XRD and confirmed by HRTEM micrographs. Rh6G released from the particles by stirring them in water at controlled speed was studied as function of time by photoluminescence. Released ratio was faster in the solid nanoparticles than in the porous ones. In the last case, a second release mechanism was observed. It was related with rhodamine coming out from the porous.
{"title":"Rh6G released from solid and nanoporous SiO2 spheres prepared by sol-gel route","authors":"J. García-Macedo, P. Francisco S., A. Franco","doi":"10.1117/12.2188976","DOIUrl":"https://doi.org/10.1117/12.2188976","url":null,"abstract":"Porous silica nanoparticles are considering good systems for drug cargo and liquid separation. In this work we studied the release of rhodamine 6G (Rh6G) from solid and porous silica nanoparticles. Solid and porous SiO2 spheres were prepared by sol-gel method. Nanoporous channels were produced by using a surfactant that was removed by chemical procedure. Rh6G was incorporated into the channels by impregnation. The hexagonal structure of the pores was detected by XRD and confirmed by HRTEM micrographs. Rh6G released from the particles by stirring them in water at controlled speed was studied as function of time by photoluminescence. Released ratio was faster in the solid nanoparticles than in the porous ones. In the last case, a second release mechanism was observed. It was related with rhodamine coming out from the porous.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"103 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127854630","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}
Colloidal quantum dots present an opportunity as infrared and liquid processed materials. Initial results in 2011 showed mid-infrared detection with HgTe colloidal quantum dots in the mi-IR range, 3-5 microns. This has been now extended to the long-wave IR, 8-12 microns. The infrared response from the HgTe colloidal quantum dots arises from the absorption of light across the gap created by the confinement. The large dots absorbing the LWIR are about 20 nm in size and the size dispersion will need improvements. While Interband absorption requires the material to be zero or small-gap semiconductors, intraband transitions have no such limitations. However, this requires doped colloidal quantum dots. Two colloidal quantum dot materials, the small gap (0.6 eV) b-HgS and the zero-gap HgSe turn out to be stably doped with electrons. This has led to the observation of Mid-IR intraband photoconduction in both systems and alternative materials for IR detection. There are several basic challenges, besides fabrication and reliability. The proximity of the surface from the excitation leads to very short excited lifetimes due to nonradiative processes. Controlling the surface will be the avenue to lengthen the lifetime, while plasmonic coupling may lead to shorter radiative lifetime. Since the surface is easily chemically modified, it also leads to strong changes in the Fermi level and this will need to be controlled. In this talk, I will describe my understanding of the potential and limitations of this material approach to infrared detection, while discussing aspects of transport, photoluminescence, doping and photovoltaic responses.
{"title":"Colloidal quantum dots for mid-infrared detection (Presentation Recording)","authors":"P. Guyot-Sionnest","doi":"10.1117/12.2186437","DOIUrl":"https://doi.org/10.1117/12.2186437","url":null,"abstract":"Colloidal quantum dots present an opportunity as infrared and liquid processed materials. Initial results in 2011 showed mid-infrared detection with HgTe colloidal quantum dots in the mi-IR range, 3-5 microns. This has been now extended to the long-wave IR, 8-12 microns. The infrared response from the HgTe colloidal quantum dots arises from the absorption of light across the gap created by the confinement. The large dots absorbing the LWIR are about 20 nm in size and the size dispersion will need improvements. While Interband absorption requires the material to be zero or small-gap semiconductors, intraband transitions have no such limitations. However, this requires doped colloidal quantum dots. Two colloidal quantum dot materials, the small gap (0.6 eV) b-HgS and the zero-gap HgSe turn out to be stably doped with electrons. This has led to the observation of Mid-IR intraband photoconduction in both systems and alternative materials for IR detection. There are several basic challenges, besides fabrication and reliability. The proximity of the surface from the excitation leads to very short excited lifetimes due to nonradiative processes. Controlling the surface will be the avenue to lengthen the lifetime, while plasmonic coupling may lead to shorter radiative lifetime. Since the surface is easily chemically modified, it also leads to strong changes in the Fermi level and this will need to be controlled. In this talk, I will describe my understanding of the potential and limitations of this material approach to infrared detection, while discussing aspects of transport, photoluminescence, doping and photovoltaic responses.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134464733","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}
J. Kumar, F. Ouchen, Devin A. Smarra, G. Subramanyam, J. Grote
In this study, we demonstrated the use of DNA-CTMA (DC) in combination with PolyVinylidene Fluoride (PVDF) as a host matrix or separator for Lithium based electrolyte to form solid polymer/gel like electrolyte for potential application in Li-ion batteries. The addition of DC provided a better thermal stability of the composite electrolyte as shown by the thermos-gravimetric analysis (TGA). The AC conductivity measurements suggest that the addition of DC to the gel electrolyte had no effect on the overall ionic conductivity of the composite. The obtained films are flexible with high mechanical stretch-ability as compared to the gel type electrolytes only.
{"title":"DNA based electrolyte/separator for lithium battery application","authors":"J. Kumar, F. Ouchen, Devin A. Smarra, G. Subramanyam, J. Grote","doi":"10.1117/12.2193780","DOIUrl":"https://doi.org/10.1117/12.2193780","url":null,"abstract":"In this study, we demonstrated the use of DNA-CTMA (DC) in combination with PolyVinylidene Fluoride (PVDF) as a host matrix or separator for Lithium based electrolyte to form solid polymer/gel like electrolyte for potential application in Li-ion batteries. The addition of DC provided a better thermal stability of the composite electrolyte as shown by the thermos-gravimetric analysis (TGA). The AC conductivity measurements suggest that the addition of DC to the gel electrolyte had no effect on the overall ionic conductivity of the composite. The obtained films are flexible with high mechanical stretch-ability as compared to the gel type electrolytes only.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133424117","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}
Recently, the use of phased array metasurfaces to control the phase and amplitude of electromagnetic waves at subwavelength dimensions have led to large number of devices ranging from flat optical elements to holographic projections. Here we analytically (and numerically using FDTD techniques) develop a design principle to form reconfigurable metasurfaces that control the phase of transmitted beam between 0 and 2π in a lossless manner. For a linearly polarized plane wave incident on a sub-wavelength array of dielectric resonators, we engineer the size of the individual resonators and the array periodicity such that the fundamental Electric and Magnetic dipole resonances of the device cross each other. This mode crossing caused by coupling of individual resonator modes with the surface lattice resonances, constructively interferes with the incident plane wave enabling us to form lossless metasurfaces. By optically pumping charge carriers into the resonators, we can tune the refractive index of the individual resonators leading to arbitrary control over the phase of the transmitted beam between 0 and 2π with less than 3dB loss in intensity. Further, we extend these strategies by redesigning the resonator elements by forming core-shell (metal-dielectric) resonators to cause the resonance matching within each resonator. This enables the mode crossing to be independent of the periodicity of the resonator elements while preserving the arbitrary control over the phase through charge carrier modulation. Such metasurfaces with spectrally overlapping electric and magnetic dipole modes may form the basis for a range of metadevices with unprecedented control over the Electromagnetic wave front.
{"title":"Dynamically reconfigurable metasurfaces (Presentation Recording)","authors":"P. Iyer, N. Butakov, J. Schuller","doi":"10.1117/12.2187811","DOIUrl":"https://doi.org/10.1117/12.2187811","url":null,"abstract":"Recently, the use of phased array metasurfaces to control the phase and amplitude of electromagnetic waves at subwavelength dimensions have led to large number of devices ranging from flat optical elements to holographic projections. Here we analytically (and numerically using FDTD techniques) develop a design principle to form reconfigurable metasurfaces that control the phase of transmitted beam between 0 and 2π in a lossless manner. For a linearly polarized plane wave incident on a sub-wavelength array of dielectric resonators, we engineer the size of the individual resonators and the array periodicity such that the fundamental Electric and Magnetic dipole resonances of the device cross each other. This mode crossing caused by coupling of individual resonator modes with the surface lattice resonances, constructively interferes with the incident plane wave enabling us to form lossless metasurfaces. By optically pumping charge carriers into the resonators, we can tune the refractive index of the individual resonators leading to arbitrary control over the phase of the transmitted beam between 0 and 2π with less than 3dB loss in intensity. Further, we extend these strategies by redesigning the resonator elements by forming core-shell (metal-dielectric) resonators to cause the resonance matching within each resonator. This enables the mode crossing to be independent of the periodicity of the resonator elements while preserving the arbitrary control over the phase through charge carrier modulation. Such metasurfaces with spectrally overlapping electric and magnetic dipole modes may form the basis for a range of metadevices with unprecedented control over the Electromagnetic wave front.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127444586","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}
Imaging is an effective tool in scientific research, manufacturing, and medical practice. However, despite its importance, it is not easy to observe dynamical events that occur much faster or slower than the human time scale (found in photochemistry, phononics, fluidics, MEMS, and tribology). Unfortunately, traditional methods for imaging fall short in visualizing them due to their technical limitations. In this talk, I will introduce radically different approaches to imaging. I will first discuss ultrafast imaging and then talk about ultraslow imaging. I will show how these imaging tools help us better understand dynamical processes.
{"title":"Extreme Imaging and Beyond (Presentation Recording)","authors":"K. Goda","doi":"10.1117/12.2192905","DOIUrl":"https://doi.org/10.1117/12.2192905","url":null,"abstract":"Imaging is an effective tool in scientific research, manufacturing, and medical practice. However, despite its importance, it is not easy to observe dynamical events that occur much faster or slower than the human time scale (found in photochemistry, phononics, fluidics, MEMS, and tribology). Unfortunately, traditional methods for imaging fall short in visualizing them due to their technical limitations. In this talk, I will introduce radically different approaches to imaging. I will first discuss ultrafast imaging and then talk about ultraslow imaging. I will show how these imaging tools help us better understand dynamical processes.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126191881","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}
Self assembly driven by complicated but systematic hierarchical interactions offers a qualified alternative for fabricating functional micron or nanometer scale pattern structures that have been potentially useful for various organic and nanotechnological devices. Self assembled nanostructures generated from synthetic polymer systems such as controlled polymer blends, semi-crystalline polymers and block copolymers have gained a great attention not only because of the variety of nanostructures they can evolve but also because of the controllability of these structures by external stimuli. In this presentation, various novel photo-electronic materials and devices are introduced based on the solution-processed low dimensional nanomaterials such as networked carbon nanotubes (CNTs), reduced graphene oxides (rGOs) and 2 dimensional transition metal dichalcogenides (TMDs) with self assembled polymers including field effect transistor, electroluminescent device, non-volatile memory and photodetector. For instance, a nanocomposite of networked CNTs and a fluorescent polymer turned out an efficient field induced electroluminescent layer under alternating current (AC) as a potential candidate for next generation displays and lightings. Furthermore, scalable and simple strategies employed for fabricating rGO as well as TMD nanohybrid films allowed for high performance and mechanically flexible non-volatile resistive polymer memory devices and broad band photo-detectors, respectively.
{"title":"Solution-processed low dimensional nanomaterials with self-assembled polymers for flexible photo-electronic devices (Presentation Recording)","authors":"Cheolmin Park","doi":"10.1117/12.2190637","DOIUrl":"https://doi.org/10.1117/12.2190637","url":null,"abstract":"Self assembly driven by complicated but systematic hierarchical interactions offers a qualified alternative for fabricating functional micron or nanometer scale pattern structures that have been potentially useful for various organic and nanotechnological devices. Self assembled nanostructures generated from synthetic polymer systems such as controlled polymer blends, semi-crystalline polymers and block copolymers have gained a great attention not only because of the variety of nanostructures they can evolve but also because of the controllability of these structures by external stimuli. In this presentation, various novel photo-electronic materials and devices are introduced based on the solution-processed low dimensional nanomaterials such as networked carbon nanotubes (CNTs), reduced graphene oxides (rGOs) and 2 dimensional transition metal dichalcogenides (TMDs) with self assembled polymers including field effect transistor, electroluminescent device, non-volatile memory and photodetector. For instance, a nanocomposite of networked CNTs and a fluorescent polymer turned out an efficient field induced electroluminescent layer under alternating current (AC) as a potential candidate for next generation displays and lightings. Furthermore, scalable and simple strategies employed for fabricating rGO as well as TMD nanohybrid films allowed for high performance and mechanically flexible non-volatile resistive polymer memory devices and broad band photo-detectors, respectively.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125333651","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}
Earlier, our group proposed a lens made of metallic nanorods, stacked in 3D arrays tapered in a conical shape. This nanolens could theoretically realize super-resolution color imaging in the visible range. The image could be magnified and transferred through metallic nanorods array. Lithography or self-assembly are common ways to fabricate such nanostructured devices. However, to precisely arrange nanorods is challenging due to the limitations to scale down components, and to increase accuracy of assembling particles in large area. Here we experimentally demonstrated 2D nanolens with long chains of metallic nanorods placed at tapered angles in a fan-like shape to magnify images. In the fabrication, we chemically synthesized gold nanorods coated with CTAB surfactant to ensure a 10 nm gap between the rods for the resonance control of nanolens. And we prepared trenches patterned by FIB lithography on a PMMA coated glass substrate. The different hydrophobicity of PMMA and CTAB coats enabled to optimize capillary force in gold nanorod solution and selectively assemble nanorods into hydrophilic trenches. Finally, we obtained 2D nanolens after lift-off of the PMMA layer. We numerically estimated the resonance property of nanorods chain and found a broad peak in the visible range located at a wavelength of 727 nm. The broadness of this peak (~178 nm) confirms that a broad range of wavelength can be resonant with this structure. This phenomenon was also confirmed experimentally by optical measurements. These results show that the combination of lithography and self-assembly has the potential to realize plasmonic nanolens.
{"title":"Metallic nanorods array for magnified subwavelength imaging (Presentation Recording)","authors":"Y. Ohashi, Bikas Ranjan, Y. Saito, P. Verma","doi":"10.1117/12.2187716","DOIUrl":"https://doi.org/10.1117/12.2187716","url":null,"abstract":"Earlier, our group proposed a lens made of metallic nanorods, stacked in 3D arrays tapered in a conical shape. This nanolens could theoretically realize super-resolution color imaging in the visible range. The image could be magnified and transferred through metallic nanorods array. Lithography or self-assembly are common ways to fabricate such nanostructured devices. However, to precisely arrange nanorods is challenging due to the limitations to scale down components, and to increase accuracy of assembling particles in large area. Here we experimentally demonstrated 2D nanolens with long chains of metallic nanorods placed at tapered angles in a fan-like shape to magnify images. In the fabrication, we chemically synthesized gold nanorods coated with CTAB surfactant to ensure a 10 nm gap between the rods for the resonance control of nanolens. And we prepared trenches patterned by FIB lithography on a PMMA coated glass substrate. The different hydrophobicity of PMMA and CTAB coats enabled to optimize capillary force in gold nanorod solution and selectively assemble nanorods into hydrophilic trenches. Finally, we obtained 2D nanolens after lift-off of the PMMA layer. We numerically estimated the resonance property of nanorods chain and found a broad peak in the visible range located at a wavelength of 727 nm. The broadness of this peak (~178 nm) confirms that a broad range of wavelength can be resonant with this structure. This phenomenon was also confirmed experimentally by optical measurements. These results show that the combination of lithography and self-assembly has the potential to realize plasmonic nanolens.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"304 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114588782","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}
The high optical transmittance, electrical conductivity, flexibility and chemical stability of graphene have triggered great interest in its application as a transparent conducting electrode material and as a potential replacement for indium doped tin oxide. However, currently available large scale production methods such as chemical vapor deposition produce polycrystalline graphene, and require additional transfer process which further introduces defects and impurities resulting in a significant increase in its sheet resistance. Doping of graphene with foreign atoms has been a popular route for reducing its sheet resistance which typically comes at a significant loss in optical transmission. Herein, we report the successful bromine doping of graphene resulting in air-stable transparent conducting electrodes with up to 80% reduction of sheet resistance reaching ~180 Ω/ at the cost of 2-3% loss of optical transmission in case of few layer graphene and 0.8% in case of single layer graphene. The remarkably low tradeoff in optical transparency leads to the highest enhancements in figure of merit reported thus far. Furthermore, our results show a controlled increase in the workfunction up to 0.3 eV with the bromine content. These results should help pave the way for further development of graphene as potentially a highly transparent substitute to other transparent conducting electrodes in optoelectronic devices.
{"title":"Bromination of graphene: a new route to making high performance transparent conducting electrodes with low optical losses (Presentation Recording)","authors":"A. Mansour, A. Amassian, M. Tanielian","doi":"10.1117/12.2187273","DOIUrl":"https://doi.org/10.1117/12.2187273","url":null,"abstract":"The high optical transmittance, electrical conductivity, flexibility and chemical stability of graphene have triggered great interest in its application as a transparent conducting electrode material and as a potential replacement for indium doped tin oxide. However, currently available large scale production methods such as chemical vapor deposition produce polycrystalline graphene, and require additional transfer process which further introduces defects and impurities resulting in a significant increase in its sheet resistance. Doping of graphene with foreign atoms has been a popular route for reducing its sheet resistance which typically comes at a significant loss in optical transmission. Herein, we report the successful bromine doping of graphene resulting in air-stable transparent conducting electrodes with up to 80% reduction of sheet resistance reaching ~180 Ω/ at the cost of 2-3% loss of optical transmission in case of few layer graphene and 0.8% in case of single layer graphene. The remarkably low tradeoff in optical transparency leads to the highest enhancements in figure of merit reported thus far. Furthermore, our results show a controlled increase in the workfunction up to 0.3 eV with the bromine content. These results should help pave the way for further development of graphene as potentially a highly transparent substitute to other transparent conducting electrodes in optoelectronic devices.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116595130","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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