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Alexander V Korovin, Nicolas L Dmitruk, Sergii V Mamykin, Viktor I Myn'ko, Mariya V Sosnova
A new approach to the formation of a 1D planar periodicity on the front of a plasmonic photodetector based on Schottky barrier is proposed. It allows forming a 1D planar periodicity with corrugation at the "metal/environment" interface by laser interference lithography using embedded chalcogenide wires, whereas the "metal/semiconductor" interface is flat that leads to reducing of surface recombination losses at Shottky barrier in contrary to the conventional technology for forming corrugated metal films on the semiconductor surface requiring chemical etching of the semiconductor substrate...
December 2017: Nanoscale Research Letters
J Ma, D A Pesin
We develop an effective medium theory for electromagnetic wave propagation through gapless nonuniform systems with a dynamic chiral magnetic effect. The theory allows us to calculate macroscopic-disorder-induced corrections to the values of optical, as well as chiral magnetic conductivities. In particular, we show that spatial fluctuations of the optical conductivity induce corrections to the effective value of the chiral magnetic conductivity. The absolute value of the effect varies strongly depending on the system parameters, but yields the leading frequency dependence of the polarization rotation and circular dichroism signals...
March 10, 2017: Physical Review Letters
Dongdong Liu, Jicheng Wang, Feng Zhang, Yuewu Pan, Jian Lu, Xiaowu Ni
A wavelength band-pass filter with asymmetric dual circular ring resonators in a metal-insulator-metal (MIM) structure is proposed and numerically simulated. For the interaction of the local discrete state and the continuous spectrum caused by the side-coupled resonators and the baffle, respectively, the transmission spectrum exhibits a sharp and asymmetric profile. By adjusting the radius and material imbedded in one ring cavity, the off-to-on plasmon-induced absorption (PIA) optical response can be tunable achieved...
March 13, 2017: Sensors
Jayachandran Venkatesan, Se-Kwon Kim, Min Suk Shim
Green synthesis of silver nanoparticles (AgNPs) has gained great interest as a simple and eco-friendly alternative to conventional chemical methods. In this study, AgNPs were synthesized by using extracts of marine algae Ecklonia cava as reducing and capping agents. The formation of AgNPs using aqueous extract of Ecklonia cava was confirmed visually by color change and their surface plasmon resonance peak at 418 nm, measured by UV-visible spectroscopy. The size, shape, and morphology of the biosynthesized AgNPs were observed by transmission electron microscopy and dynamic light scattering analysis...
December 6, 2016: Nanomaterials
Jin-Ho Lee, Taek Lee, Jeong-Woo Choi
In tissue engineering and regenerative medicine, monitoring the status of stem cell differentiation is crucial to verify therapeutic efficacy and optimize treatment procedures. However, traditional methods, such as cell staining and sorting, are labor-intensive and may damage the cells. Therefore, the development of noninvasive methods to monitor the differentiation status in situ is highly desirable and can be of great benefit to stem cell-based therapies. Toward this end, nanotechnology has been applied to develop highly-sensitive biosensors to noninvasively monitor the neural differentiation of stem cells...
November 28, 2016: Nanomaterials
Pingping Qiu, Weibin Qiu, Zhili Lin, Houbo Chen, Yixin Tang, Jia-Xian Wang, Qiang Kan, Jiao-Qing Pan
In this paper, one-dimensional (1D) and two-dimensional (2D) graphene-based plasmonic photonic crystals (PhCs) are proposed. The band structures and density of states (DOS) have been numerically investigated. Photonic band gaps (PBGs) are found in both 1D and 2D PhCs. Meanwhile, graphene-based plasmonic PhC nanocavity with resonant frequency around 175 THz, is realized by introducing point defect, where the chemical potential is from 0.085 to 0.25 eV, in a 2D PhC. Also, the bending wvaguide and the beam splitter are realized by introducing the line defect into the 2D PhC...
September 9, 2016: Nanomaterials
Wenbin Liu, Jianfa Zhang, Zhihong Zhu, Xiaodong Yuan, Shiqiao Qin
In this paper, anisotropic graphene plasmonic structures are explored for light trapping and absorption enhancement in surrounding media. It is shown that electrically tunable and versatile spectral and polarization selectivity can be realized. Particularly, it is possible to control absorption of the incident light's polarization component at a specific wavelength by varying the Fermi energy with suitable geometric designs. It may find applications for new types of infrared and THz photodetectors and will promote the research of other novel polarization devices...
August 23, 2016: Nanomaterials
Boxuan Shen, Kosti Tapio, Veikko Linko, Mauri A Kostiainen, Jari Jussi Toppari
Metallic nanostructures have inspired extensive research over several decades, particularly within the field of nanoelectronics and increasingly in plasmonics. Due to the limitations of conventional lithography methods, the development of bottom-up fabricated metallic nanostructures has become more and more in demand. The remarkable development of DNA-based nanostructures has provided many successful methods and realizations for these needs, such as chemical DNA metallization via seeding or ionization, as well as DNA-guided lithography and casting of metallic nanoparticles by DNA molds...
August 10, 2016: Nanomaterials
Won-Yeop Rho, Myeung-Hwan Chun, Ho-Sub Kim, Hyung-Mo Kim, Jung Sang Suh, Bong-Hyun Jun
Dye-sensitized solar cells (DSSCs) were fabricated using open-ended freestanding TiO₂ nanotube arrays functionalized with Ag nanoparticles (NPs) in the channel to create a plasmonic effect, and then coated with large TiO₂ NPs to create a scattering effect in order to improve energy conversion efficiency. Compared to closed-ended freestanding TiO₂ nanotube array-based DSSCs without Ag or large TiO₂ NPs, the energy conversion efficiency of closed-ended DSSCs improved by 9.21% (actual efficiency, from 5...
June 15, 2016: Nanomaterials
Antonella Gentile, Francesco Ruffino, Maria Grazia Grimaldi
Due to their peculiar qualities, metal-based nanostructures have been extensively used in applications such as catalysis, electronics, photography, and information storage, among others. New applications for metals in areas such as photonics, sensing, imaging, and medicine are also being developed. Significantly, most of these applications require the use of metals in the form of nanostructures with specific controlled properties. The properties of nanoscale metals are determined by a set of physical parameters that include size, shape, composition, and structure...
June 6, 2016: Nanomaterials
Yiming Bai, Lingling Yan, Jun Wang, Lin Su, Zhigang Yin, Nuofu Chen, Yuanyuan Liu
A way to increase the photocurrent of top-cell is crucial for current-matched and highly-efficient GaInP/GaInAs/Ge triple-junction solar cells. Herein, we demonstrate that ellipsoidal silver nanoparticles (Ag NPs) with better extinction performance and lower fabrication temperature can enhance the light harvest of GaInP/GaInAs/Ge solar cells compared with that of spherical Ag NPs. In this method, appropriate thermal treatment parameters for Ag NPs without inducing the dopant diffusion of the tunnel-junction plays a decisive role...
May 25, 2016: Nanomaterials
Yinan Zhang, Boyuan Cai, Baohua Jia
Plasmonic metal nanoparticles supporting localized surface plasmon resonances have attracted a great deal of interest in boosting the light absorption in solar cells. Among the various plasmonic materials, the aluminium nanoparticles recently have become a rising star due to their unique ultraviolet plasmonic resonances, low cost, earth-abundance and high compatibility with the complementary metal-oxide semiconductor (CMOS) manufacturing process. Here, we report some key factors that determine the light incoupling of aluminium nanoparticles located on the front side of silicon solar cells...
May 24, 2016: Nanomaterials
Kondareddy Cherukula, Kamali Manickavasagam Lekshmi, Saji Uthaman, Kihyun Cho, Chong-Su Cho, In-Kyu Park
Nanotechnology has enabled the development of many alternative anti-cancer approaches, such as thermal therapies, which cause minimal damage to healthy cells. Current challenges in cancer treatment are the identification of the diseased area and its efficient treatment without generating many side effects. Image-guided therapies can be a useful tool to diagnose and treat the diseased tissue and they offer therapy and imaging using a single nanostructure. The present review mainly focuses on recent advances in the field of thermal therapy and imaging integrated with multifunctional inorganic nanoparticles...
April 18, 2016: Nanomaterials
Muhammad Akram Raza, Zakia Kanwal, Anum Rauf, Anjum Nasim Sabri, Saira Riaz, Shahzad Naseem
Silver nanoparticles (AgNPs) of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC) and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP) was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM), UV-visible spectroscopy (UV-VIS), and X-ray diffraction (XRD) techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm...
April 15, 2016: Nanomaterials
Van-Duong Dao, Ho-Suk Choi
Plasmon-assisted energy conversion is investigated in a comparative study of dye-sensitized solar cells (DSCs) equipped with photo-anodes, which are fabricated by forming gold (Au) and silver (Ag) nanoparticles (NPs) on an fluorine-doped tin oxide (FTO) glass surface by means of dry plasma reduction (DPR) and coating TiO₂ paste onto the modified FTO glass through a screen printing method. As a result, the FTO/Ag-NPs/TiO₂ photo-anode showed an enhancement of its photocurrent, whereas the FTO/Au-NPs/TiO₂ photo-anode showed less photocurrent than even a standard photo-anode fabricated by simply coating TiO₂ paste onto the modified FTO glass through screen printing...
April 14, 2016: Nanomaterials
Yangyang Zhao, Jing Zhao, Guiye Shan, Dongmei Yan, Yanwei Chen, Yichun Liu
It is important to control drug release and detect the distribution of drug molecules before and after release. In this work, liposome@AgAu nanocomposite is prepared for drug delivery, which not only can control drug release by near infrared laser irradiation but also can monitor drug molecules by surface enhanced Raman scattering (SERS) and fluorescence signal during the release process. The liposome@AgAu core/shell nanocomposite prepared by the galvanic replacement reaction (GRR) shows tunable localized surface plasmon resonance (LSPR) absorption peaks from visible to near-infrared region and good biocompatibility...
March 8, 2017: Colloids and Surfaces. B, Biointerfaces
Jun Lu, Yi-Xin Chang, Ning-Ning Zhang, Ying Wei, Ai-Ju Li, Jia Tai, Yao Xue, Zhao-Yi Wang, Yang Yang, Li Zhao, Zhong-Yuan Lu, Kun Liu
Gold nanorods are excellent anisotropic building blocks for plasmonic chiral nanostructures. The near-infrared plasmonic band of nanorods makes them highly desirable for biomedical applications such as chiral bioimaging and sensing, in which a strong circular dichroism (CD) signal is required. Chiral assemblies of gold nanorods induced by self-associating peptides are especially attractive for this purpose as they exhibit plasmonic-enhanced chiroptical activity. Here, we showed that the presence of cetyltrimethylammonium bromide (CTAB) micelles in a gold nanorod solution promoted the self-association of l-/d-glutathione (GSH) and significantly enhanced the chirality of the resulting plasmonic nanochains...
March 23, 2017: ACS Nano
Dong Wu, Yumin Liu, Li Yu, Zhongyuan Yu, Lei Chen, Ruifang Li, Rui Ma, Chang Liu, Jinqiannan Zhang, Han Ye
In this work, using finite-difference time-domain method, we propose and numerically demonstrate a novel way to achieve electromagnetically induced transparency (EIT) phenomenon in the reflection spectrum by stacking two different types of coupling effect among different elements of the designed metamaterial. Compared with the conventional EIT-like analogues coming from only one type of coupling effect between bright and dark meta-atoms on the same plane, to our knowledge the novel approach is the first to realize the optically active and precise control of the wavelength position of EIT-like phenomenon using optical metamaterials...
March 23, 2017: Scientific Reports
Andreas Polywka, Christian Tückmantel, Patrick Görrn
Metal nanoparticles show a particularly strong interaction with light, which is the basis for nanoparticle plasmonics. One of the main goals of this emerging research field is the alignment of nanoparticles and their integration into sophisticated nanostructures providing a tailored interaction with light. This assembly of nanoparticles at well-controlled substrate sites often involves expensive technological approaches, such as electron beam lithography in order to fabricate the nanoparticle structures. Furthermore difficult numerical simulations are needed to predict their optical properties...
March 23, 2017: Scientific Reports
Maureen J Lagos, Andreas Trügler, Ulrich Hohenester, Philip E Batson
Imaging of vibrational excitations in and near nanostructures is essential for developing low-loss infrared nanophotonics, controlling heat transport in thermal nanodevices, inventing new thermoelectric materials and understanding nanoscale energy transport. Spatially resolved electron energy loss spectroscopy has previously been used to image plasmonic behaviour in nanostructures in an electron microscope, but hitherto it has not been possible to map vibrational modes directly in a single nanostructure, limiting our understanding of phonon coupling with photons and plasmons...
March 22, 2017: Nature
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