Effects of hydrophobic and electrostatic interactions on the self-assembling process of the ionic-complementary peptide EMK16-II are investigated by atomic force microscopy imaging, circular dichroism spectra, light scattering, and chromatography. It is found that the hydrophobicity of the peptide promotes the aggregation in pure water even at a very low concentration, resulting in a much lower critical aggregation concentration than that of another peptide, EAK16-II. The effect of anions in solution with different valences on electrostatic interactions is also important. Monovalent anions (Cl^- and Ac^-) with a proper concentration can facilitate the formation of peptide fibrils, with Cl^- of smaller size being more effective than Ac^- of larger size. However, only small amounts of fibrils, but plenty of large amorphous aggregates, are found when the peptide solution is incubated with multivalent anions, such as SO^2-₄, C₆H₅O^3-₇, and HPO^2-₄. More importantly, by gel filtration chromatography, the citrate anion, which induces a similar effect on the self-assembling process of EMK16-II as that of SO^2-₄ and HPO^2-₄, can interact with two or more positively charged residues of the peptide and reside in the amorphous aggregates. This implies a "salt bridge" effect of multivalent anions on the peptide self-assembling process, which can interpret a previous puzzle why divalent cations inhibit the formation of ordered nanofibrils of the ioniccomplementary peptides. Thus, our results clarify the important effects of hydrophobic and electrostatic interactions on the self-assembling process of the ioniccomplementary peptides. These are greatly helpful for us to understand the mechanism of peptides' self-assembling process and protein folding and aggregation.

Dawei Zou;Zuoxiu Tie;Chunmei Lu;Meng Qin;笑梅 吕;牧 王;炜 王;P. Chen

Biopolymers

2010-4

We demonstrate theoretically in this work the existence of dual Fano resonances in a silicon nanodimer, which result from the strong coupling between the magnetic dipole in one nanocylinder and the electric dipole in another. It is shown that the intensities of the Fano resonances can be controlled by changing the polarization of the incident light, and the wavelengths of the resonances can be shifted by varying the separation of nanocylinders. And a broadband scattering response is also presented. These results concerning the ohmic loss-less, easily fabricated silicon nanodimer may have promising applications in wave filters, solar cells, biosensing, etc.

Zhi Yong Jia;Jing Ning Li;Hong Wei Wu;Cheng Wang;Tian Yong Chen;茹雯 彭;牧 王

Journal of Applied Physics

2016-2-21

We demonstrate experimentally hybrid couplings among molecular excitons, plasmonic and photonic modes in the organic-dye-doped nanostructures. And multiple hybrid polariton bands are observed, which may achieve potential applications on multimode polariton lasers and optical spectroscopy.

茹雯 彭;Kun Zhang;Yue Xu;Wen Bo Shi;Ren Hao Fan;牧 王

2017

(Ba_0.5Sr_0.5)TiO₃ (BST) thin films were deposited on Si and plantinized Si substrates using sol-gel method with rapid thermal annealing (RTA). The films were characterized by inductive coupled plasma (ICP) analysis, X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM) and electrical measurements. BST get well crystallized after RTA at 700 °C for 5 min. Grain size, grain height, and thus, surface roughness and film density increase with the increase of annealing time. SEM cross-section results clearly demonstrate a better BST/substrate interface compared with conventional annealing. The dielectric constant and loss tangent of BST films at 10 kHz are 435 and 0.069, respectively. This good dielectric property is believed to arise from the better BST/substrate interface.

镝 吴;Aidong Li;Huiqin Ling;Xiaobo Yin;Chuanzhen Ge;牧 王;Naiben Ming

Applied Surface Science

2000-10-2

A fractal-featured metallic thin film with Sierpinski Carpet pattern is fabricated on silicon wafer by microfabrication techniques. Transmission infrared spectroscopy indicates that there exists extraordinary high transmission at specific wavelengths, which can be ascribed to the effect of surface plasmon resonance, and are determined by hierarchy of apertures of different sizes in the fractal structure. This patterned film provides a unique system to achieve enhanced transmission simultaneously at different selected frequencies of electromagnetic wave.

Yong Jun Bao;Bo Zhang;Zhe Wu;Jian Wen Si;牧 王;茹雯 彭;Xiang Lu;Jun Shao;志锋 李;Xi Ping Hao;Nai Ben Ming

Applied Physics Letters

2007

Using polymer droplets formed in dewetting of polymer film on silicon surface as template, the silicon columns capped with circular polymer plates are fabricated via plasma etching. By blanket deposition of a gold layer on the structure, an array of metallic microcavities featured by a metal circular plate separated by a silicon column with the bottom metallic film is achieved. The geometrical parameters of the stereo structures can be tuned. We show that the electric field at the edge of the cap is greatly enhanced, which can be used as the hot spot for trace amount of chemical detection.

Xiao Chun Chen;Yuan Wei Wu;Yu Hui Hu;Hong Min Li;茹雯 彭;Xi Ping Hao;牧 王

Applied Physics Letters

2013-1-14

The efficiency of photoluminescence (PL) of transition-metal dichalcogenides (TMDCs) significantly influences their practical applications in optoelectronic devices. In this work, we study multiple coupling among excitons, surface plasmons, and optical modes, and their effects on PL of monolayer MoS₂ atop plasmonic nanohole arrays. Under the illumination of visible light, strong intensity enhancement of PL from monolayer MoS₂ is observed in the system. We further demonstrate that there exist excitons induced from MoS₂, localized and propagating surface plasmons excited from nanoholes, and optical modes related to the incident laser. And hybrid coupling of those modes significantly improves the PL signals and also lightens the PL images of monolayer MoS₂. This work provides a unique way to improve the emission of monolayer TMDCs. The atomically thin TMDCs coupled to plasmonic metamaterials are also promising for advanced applications such as ultrathin integrated light-emission diodes, photodetection, and nanolasers.

Wen Bo Shi;Lei Zhang;Di Wang;Rui Li Zhang;Yingying Zhu;Li Heng Zhang;茹雯 彭;Wenzhong Bao;Ren Hao Fan;牧 王

Optics Letters

2018-9-1

We report here the experimental observations that the tip topography of ZnO nano-prisms sensitively depends on the percentage of oxygen in the flux of the carrying gas in vapor growth. At a relatively high oxygen concentration, a number of thin filaments can be nucleated atop nano-prisms, forming a unique fish-spear-like multi-tip morphology. The length and density of the "spear tines" depend on the flux of the carrying gas. The field emission properties of the nanorod array with different tip morphology are investigated. The structures with longer and denser spear tines possess lower turn-on electric field and higher electric current density. The cathodoluminescence properties of the ZnO nano-prisms have also been studied. The luminescence related to defects in multi-tip nano-prisms possesses the strongest intensity, and the nanorod without any tine structure possesses the lowest defect luminescence intensity. The intrinsic luminescence of ZnO around 385 nm, however, has the opposite tendency. We suggest that our observation is inspiring in optimizing the emission properties of the nanowire devices.

Ming Liu;Cong Meng;Zheng Hong Xue;Xiang Xiong;大军 舒;茹雯 彭;强 巫;征 胡;牧 王

Europhysics Letters

2013-10

Fei Chen;Jingning Li;Fangfang Yu;Di Zhao;Fan Wang;Yanbin Chen;茹雯 彭;牧 王

Advanced Materials

2016-9

Surface plasmon polaritons (SPPs) propagating on a metal-dielectric interface suffer from inevitable energy losses originating from metals, especially in a visible regime, which degrades the quality of SPP-based devices. However, if the size of the devices is sufficiently miniaturized, we can thereby limit the propagation length of the signals and effectively circumvent the problems of large propagation losses. Anderson localization is a possible approach to squeeze SPPs. In this Letter, we experimentally demonstrate the Anderson localization of SPPs at optical frequencies in two-dimensional (2D) nanostructures. By increasing the positional disorder of the silver nanohole arrays on a glass substrate, strong 2D localization of SPPs appears with an exponentially decreased electric field, reduced propagation length, and the rapid disappearance of the autocorrelation coefficient. Moreover, we manage to realize the localized SPP-exciton interactions in the 2D disordered silver nanoarrays combined with fluorescent dye molecules. Due to the disorder in the nanoarray, the collected photoluminescence from fluorescent dye molecules is enhanced by over three orders of magnitude compared to that on the silver film without nanostructures. Our study extends Anderson localization of SPPs at the visible regime to 2D disordered systems and provides a unique way to enhance light-matter interaction in SPP-based nanodevices.

Yingying Zhu;Hao Jing;茹雯 彭;Cheng Yao Li;Jie He;Bo Xiong;牧 王

Applied Physics Letters

2020-5-18