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Laser Polymer Tattooing: A Versatile Method for Permanent Marking on Polymer Surfaces
(2019-12-01)
Chang, Po-Yi
;
Bruntz, Adele
;
Vidal, Loic
;
Vetter, Pierre-Alain
;
Roudot, Patrick
A versatile and efficient method for the permanent marking of polymer surfaces that combines inkjet deposition and near-infrared (NIR) laser curing is investigated. The NIR laser treatment forces the ink particles to migrate into the upper layers of the polymer. This results in the fixation of a permanent grayscale image that can be applied to various polymers, such as polypropylene, which is widely used in industry but still difficult to mark. The physiochemical processes induced by laser curing are investigated by electronic and optical microscopy. The dependence of the thickness of the deposited ink and the laser power on the contrast of marking are also studied. A mechanism implying fast laser-induced melting of the polymer surface followed by displacement of carbon nanoparticles by convection is proposed. Finally, a comparison of the aging properties of samples prepared by this process and standard UV ink is proposed to illustrate the interesting nature of this new polymer marking process. Integrating the ink under the surface of the polymer, as in a skin tattooing procedure, by laser curing is an efficient way to generate permanent images on polymer surfaces.
Selective Control of Cell Activity with Hydrophilic Polymer-Covered Cationic Nanoparticles
(1970-01-01)
Lin, Hsiu-Pen
;
Akimoto, Jun
;
Li, Yaw-Kuen
;
Ito, Yoshihiro
;
交大名義發表
Cationic polymers exhibit high cytotoxicity via strong interaction with cell membranes. To reduce cell membrane damage, a hydrophilic polymer is introduced to the cationic nanoparticle surface. The hydrophilic polymer coating of cationic nanoparticles resulted in a nearly neutral nanoparticle. These particles are applied to mouse fibroblast (3T3) and human cervical adenocarcinoma (Hela) cells. Interestingly, nanoparticles with a long cationic segment decrease cell activity regardless of cell type, while those with a short segment only affect 3T3 cell activity at lower concentrations less than 500 mu g mL(-1). Most nanoparticles are located inside 3T3 cells but on the cell membrane of Hela cells. The short cationic nanoparticle shows negligible cell membrane damage despite its high accumulation on Hela cell membranes. Cell activity changed by hydrophilic polymer-coated cationic nanoparticles is caused by incorporated nanoparticle accumulation in the cells, not cell membrane damage. To suppress the cytotoxicity from the cationic polymer, cationic nanoparticle needs to completely cover with hydrophilic polymer so as not to exhibit the cationic effect and applies to cell with low concentrations to reduce the nonselective cytotoxicity from the cationic polymer.
Effective Promotion of Oxygen Reduction Reaction by in Situ Formation of Nanostructured Catalyst
(2019-08-01)
Chen, Yu
;
Yoo, Seonyoung
;
Zhang, Weilin
;
Kim, Jun Hyuk
;
Zhou, Yucun
Efficient electrocatalysts for oxygen reduction reaction (ORR) are critical to high-performance energy conversion and storage devices. As an important family of functional materials, alkaline earth metal oxides are generally considered inert toward electrochemical reactions. Here we report the remarkable enhancement of ORR activity and durability of electrodes enabled by surface modification with, a precursor of barium nitrate. During cell start-up process, an ORR active cobaltite catalyst was in situ formed on the electrode surface, as confirmed by scanning transmission electron microscopy (STEM) analysis. A combination of in situ/operando Raman and electrochemical impedance study suggests that the transition from nitrate to cobaltite may occur at similar to 565 degrees C. The peak power density of a single cell at 750 degrees C is increased from similar to 0.85 to similar to 1.15 W cm(-2) (35% increase) by the surface modification, demonstrating the remarkable enhancement of electrocatalytic activity under realistic operating conditions.
Efficient Optical Trapping of Nano-Particle via Waveguide-Coupled Hybrid Plasmonic Nano-Taper
(2019-06-01)
Lin, Yi-Chang
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
For manipulating nano-bio-specimens, we propose a tweezing device by integrating a triangular-shaped photonic-plasmonic nano-taper on top of a coupling waveguide. The device can exert strong trapping force on nano-particle owing to efficient optical energy usage and accessible field distribution. Working principle and optical characteristics of the device are fully investigated and discussed. The optimized device shows an excellent trapping capability with low threshold power of 3.57 mW for stable trapping n 100 nm polystyrene particle. Simple geometry and high tolerance to pattern misalignment between trap unit and coupling waveguide are beneficial for realistic fabrication. Furthermore, the footprint of trap unit is only 400 nm x 625 nm. We believe this design will be very useful to the development of lab-on-a-chip system.
Efficient Optical Trapping and Detection of Nanoparticle Via Plasmonic Bowtie Notch
(2019-04-01)
Lin, Yi-Chang
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
For manipulating nanoparticles, we propose a nanotweezer named plasmonic bowtie notch (PBN) by adding a thin metal film to the bottom of plasmonic bowtie aperture. The PBN can exert a large trapping force on nanoparticle because the enhanced field of resonance mode can be much accessed by nanoparticle. The optical properties and factors influencing trapping force of PBN are fully investigated and discussed. The optimized PBN shows an excellent trapping capability with ultralow threshold excitation intensity of 0.64 mW/mu m(2) for stable trapping of a 100 nm polystyrene particle. In addition, it provides a label-free detection of the trapped particle by observing the extinction spectrum. The sensitivity to trapped target size of 71 pm redshift in peak wavelength per 1 nm increase of particle size is relatively high compared with those obtained from most near-field tweezers. Furthermore, the footprint of PBN is only 200 nm x 220 nm. The capabilities of the proposed design show a great potential in the application of nanoparticle trapping and sensing.
Effect of Metal Ions on Hybrid Graphite-Diamond Nanowire Growth: Conductivity Measurements from a Single Nanowire Device
(2019-03-11)
Shellaiah, Muthaiah
;
Chen, Ying-Chou
;
Simon, Turibius
;
Li, Liang-Chen
;
Sun, Kien Wen
Novel Cd2+ ions mediated reproducible hybrid graphite-diamond nanowire (G-DNWs; Cd2+-NDS1 NW) growth from 4-Amino-5-phenyl-4H-1,2,4-triazole-3-thiol (S1) functionalized diamond nanoparticles (NDS1) via supramolecular assembly is reported and demonstrated through TEM and AFM images. FTIR, EDX and XPS studies reveal the supramolecular coordination between functional units of NDS1 and Cd2+ ions towards NWs growth. Investigations of XPS, XRD and Raman data show the covering of graphite sheath over DNWs. Moreover, HR-TEM studies on Cd2+-NDS1 NW confirm the coexistence of less perfect sp(2) graphite layer and sp(3) diamond carbon along with impurity channels and flatten surface morphology. Possible mechanisms behind the G-DNWs growth are proposed and clarified. Subsequently, conductivity of the as-grown G-DNWs is determined through the fabrication of a single Cd2+-NDS1 NW device, in which the G-DNW portion L2 demonstrates a better conductivity of 2.31 x 10(-4) mS/cm. In addition, we investigate the temperature-dependent carrier transport mechanisms and the corresponding activation energy in details. Finally, comparisons in electrical resistivities with other carbon-based materials are made to validate the importance of our conductivity measurements.
Synthesis of Mesoporous Nanocrystalline TiO2 Films in a Premixed H-2/O-2/Ar Flame
(2012-01-01)
Korobeinichev, O. P.
;
Shmakov, A. G.
;
Maksyutov, R. A.
;
Tereshchenko, A. G.
;
Knyazkov, D. A.
The synthesis of mesoporous nanocrystalline TiO2 films in a premixed (in vol %) 12.9/14.4/72.7 H-2/O-2/Ar flame doped with 0.1% titanium tetraisopropoxide [Ti(OC3H7)(4)] was studied. Stabilization of the flame and deposition of TiO2 nanoparticles were carried on the plane of a rotating disk. Spatial distributions of temperature and concentrations of major species in the flame were investigated. The applicability of the employed kinetic reaction scheme and the calculation method to the description of the structure of the investigated flame was tested. It was established that this method can be used to synthesize spherical crystalline nanoparticles of the anatase polymorphic form of TiO2 with an average diameter of 12 nm and a narrow size distribution (sigma = 1.45), which can be used in the production of solar cells and gas analyzer sensors.
Interrelation of transport and optical properties in gold nanoclusters
(2010-09-20)
Shu, G. W.
;
Chen, T. Y.
;
Shen, J. L.
;
Lin, C. A. J.
;
Chang, W. H.
Temperature dependence of the electrical conductivity and photoluminescence (PL) in Au nanoclusters (NCs) is investigated. The correlation of the conductivity and PL in Au NCs at different temperatures is evident: (i) for T < 50 K, both the conductivity and PL intensity decrease with temperature, which suggests thermal structural fluctuations; (ii) for 50 K < T < 90 K, conductivity and PL are explained by variable range hopping; (iii) for 90 K < T < 170 K, simple thermal activated hopping dominates in conductivity, with a rate-equation model proposed to analyze the carrier transfer in PL. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3491288]
Functionalization of Graphene Oxide Films with Au and MoOx Nanoparticles as Efficient p-Contact Electrodes for Inverted Planar Perovskite Solar Cells
(2018-09-12)
Bhosale, Sumit S.
;
Jokar, Efat
;
Fathi, Amir
;
Tsai, Cheng-Min
;
Wang, Chi-Yung
A graphene oxide (GO) film is functionalized with metal (Au) and metal-oxide (MoOx) nanoparticles (NPs) as a hole-extraction layer for high-performance inverted planar-heterojunction perovskite solar cells (PSCs). These NPs can increase the work function of GO, which is confirmed with X-ray photoelectron spectra, Kelvin probe force microscopy, and ultraviolet photoelectron spectra measurements. The down-shifts of work functions lead to a decreased level of potential energy and hence increased V-oc of the PSC devices. Although the GO-AuNP film shows rapid hole extraction and increased V-oc, a J(sc) improvement is not observed because of localization of the extracted holes inside the AuNP that leads to rapid charge recombination, which is confirmed with transient photoelectric measurements. The power conversion efficiency (PCE) of the GO-AuNP device attains 14.6%, which is comparable with that of the GO-based device (14.4%). In contrast, the rapid hole extraction from perovskite to the GO-MoOx layer does not cause trapping of holes and delocalization of holes in the GO film accelerates rapid charge transfer to the indium tin oxide substrate; charge recombination in the perovskite/GO-MoOx interface is hence significantly retarded. The GO-MoOx device consequently shows significantly enhanced V-oc and J(sc), for which its device performance attains PCE of 16.7% with great reproducibility and enduring stability.
Multi-wavelength laser tuning based on cholesteric liquid crystals with nanoparticles
(2016-04-27)
Chen, Sheng-Chieh
;
Lin, Jia-De
;
Lee, Chia-Rong
;
Hwang, Shug-June
;
影像與生醫光電研究所
A controllable multi-wavelength laser from a dye-doped cholesteric liquid crystal (DDCLC) cell is demonstrated by incorporating self-assembled polyhedral oligomeric silsesquioxane (POSS) nanoparticles (NPs). Multi-wavelength lasing emission is achieved by formation of multiple planar domains; this formation is dominantly influenced by the vertical alignment of NP clusters adsorbed on the substrate surface through a rapid thermal annealing process. The multi-wavelength lasing peaks are generated through the resultant effect of multiple longitudinal resonant modes of a Fabry-Perot etalon between the cell substrates and the amplification of fluorescence photons with the resonant wavelengths within the broadening long-wavelength edge of the reflection band of the multi-domain CLC. The amount of multi-wavelength lasing peaks can be controlled by changing the POSS NP concentration and the cooling rate of the cell. Furthermore, thermo-reversible control of the multi-wavelength lasing emission can be attained by controlling the thermally induced phase separation process of the POSS/DDCLC cell via a heating/cooling cyclic process.

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