Publications (58)112.84 Total impact
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Article: Fabrication and multifunction integration of microfluidic chips by femtosecond laser direct writing.
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ABSTRACT: In the pursuit of modern microfluidic chips with multifunction integration, micronanofabrication techniques play an increasingly important role. Despite the fact that conventional fabrication approaches such as lithography, imprinting and soft lithography have been widely used for the preparation of microfluidic chips, it is still challenging to achieve complex microfluidic chips with multifunction integration. Therefore, novel micronanofabrication approaches that could be used to achieve this end are highly desired. As a powerful 3D processing tool, femtosecond laser fabrication shows great potential to endow general microfluidic chips with multifunctional units. In this review, we briefly introduce the fundamental principles of femtosecond laser micronanofabrication. With the help of laser techniques, both the preparation and functionalization of advanced microfluidic chips are summarized. Finally, the current challenges and future perspective of this dynamic field are discussed based on our own opinion.Lab on a Chip 03/2013; · 5.67 Impact Factor -
Article: Hyper-branched CdTe nanostructures based on the self-assembling of quantum dots and their optical properties.
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ABSTRACT: As the priority of interconnects and active components in nanoscale optical and electronic devices, three-dimensional hyper-branched nanostructures came into focus of research. Recently, a novel crystallization route, named as "nonclassical crystallization," has been reported for three-dimensional nanostructuring. In this process, Quantum dots are used as building blocks for the construction of the whole hyper-branched structures instead of ions or single-molecules in conventional crystallization. The specialty of these nanostructures is the inheritability of pristine quantum dots' physical integrity because of their polycrystalline structures, such as quantum confinement effect and thus the luminescence. Moreover, since a longer diffusion length could exist in polycrystalline nanostructures due to the dramatically decreased distance between pristine quantum dots, the exciton-exciton interaction would be different with well dispersed quantum dots and single crystal nanostructures. This may be a benefit for electron transport in solar cell application. Therefore, it is very necessary to investigate the exciton-exciton interaction in such kind of polycrystalline nanostructures and their optical properites for solar cell application. In this research, we report a novel CdTe hyper-branched nanostructures based on self-assembly of CdTe quantum dots. Each branch shows polycrystalline with pristine quantum dots as the building units. Both steady state and time-resolved spectroscopy were performed to investigate the properties of carrier transport. Steady state optical properties of pristine quantum dots are well inherited by formed structures. While a suppressed multi-exciton recombination rate was observed. This result supports the percolation of carriers through the branches' network.Journal of Nanoscience and Nanotechnology 02/2013; 13(2):1607-11. · 1.56 Impact Factor -
Article: "Overpass" at the junction of a crossed microchannel: An enabler for 3D microfluidic chips.
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ABSTRACT: Reported here is the design and fabrication of three-dimensional (3D) "overpass" microstructures at the junction of crossed microfluidic channels by femtosecond laser direct writing of photopolymers. The post-integrated overpass could be used for guiding different microfluids across the junction without mixing; therefore it is proposed as an enabler for achieving 3D microfluidic chips based on conventional two-dimensional (2D) microchannels. As representative examples, bi-crossed and tri-crossed microchannels have been equipped with bi-connected and tri-connected overpasses, respectively. Flow tests confirm 3D flowing capability. The integration of such overpass structures at the microchannel junction provides an opportunity to impart 3D capability to conventional 2D microchips, thus the method may hold great promise for both functionalization and miniaturization of Lab-on-a-Chip systems.Lab on a Chip 08/2012; 12(20):3866-9. · 5.67 Impact Factor -
Article: Biomimetic graphene films and their properties.
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ABSTRACT: Biomimetic fabrication has long been considered a short cut to the rational design and production of artificial materials or devices that possess fascinating properties, just like natural creatures. Considering the fact that graphene exhibits a lot of exceptional properties in a wide range of scientific fields, biomimetic fabrication of graphene multiscale structures, denoted as biomimetic graphene, is of great interest in both fundamental research and industrial applications. Especially, the combination of graphene with biomimetic structures would realize structural and functional integrity, and thus bring a new opportunity of developing novel graphene-based devices with remarkable performance. In this feature article, we highlight the recent advances in biomimetic graphene films and their structure-defined properties. Functionalized graphene films with multiscale structures inspired from a wide range of biomaterials including rose petals, butterfly wings, nacre and honeycomb have been collected and presented. Moreover, both current challenges and future perspectives of biomimetic graphene are discussed. Although research of the so-called "biomimetic graphene" is still at an early stage, it might become a "hot topic" in the near future.Nanoscale 07/2012; 4(16):4858-69. · 5.91 Impact Factor -
Article: Highly efficient SERS test strips.
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ABSTRACT: We present a facile production approach to highly efficient SERS test strips by physical vapor deposition of silver on paper, which contains natural wrinkle and fibril structures. The SERS test strips open the door to highly sensitive (e.g., 10(-10) M) SERS detection in a convenient fashion.Chemical Communications 05/2012; 48(47):5913-5. · 6.17 Impact Factor -
Article: Biomimetic graphene surfaces with superhydrophobicity and iridescence.
Chemistry - An Asian Journal 02/2012; 7(2):301-4. · 4.50 Impact Factor -
Article: On-chip fabrication of silver microflower arrays as a catalytic microreactor for allowing in situ SERS monitoring.
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ABSTRACT: Silver microflower arrays constructed by upright nanoplates and attached nanoparticles were fabricated inside a microfluidic channel, thus a robust catalytic microreactor for allowing in situ SERS monitoring was proposed. On-chip catalytic reduction shows that the silver microflowers have high catalytic activity and SERS enhancement.Chemical Communications 12/2011; 48(11):1680-2. · 6.17 Impact Factor -
Article: A SERS-active microfluidic device with tunable surface plasmon resonances.
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ABSTRACT: A surface-enhanced Raman scattering (SERS)-active microfluidic device with tunable surface plasmon resonances is presented here. It is constructed by silver grating substrates prepared by two-beam laser interference of photoresists and subsequent metal evaporation coating, as well as PDMS microchannel derived from soft lithography. By varying the period of gratings from 200 to 550 nm, surface plasmon resonances (SPRs) from the metal gratings could be tuned in a certain range. When the SPRs match with the Raman excitation line, the highest enhancement factor of 2×10(7) is achieved in the SERS detection. The SERS-active microchannel with tunable SPRs exhibits both high enhancement factor and reproducibility of SERS signals, and thus holds great promise for applications of on-chip SERS detection.Electrophoresis 11/2011; 32(23):3378-84. · 3.30 Impact Factor -
Article: Solvothermal synthesis of nanoporous polymer chalk for painting superhydrophobic surfaces.
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ABSTRACT: Reported here is a facile synthesis of nanoporous polymer chalk for painting superhydrophobic surfaces. Taking this nanoporous polymer as a media, superhydrophobicity is rapidly imparted onto three typical kinds of substrates, including paper, transparent polydimethylsiloxane (PDMS), and finger skin. Quantitative characterization showed that the adhesion between the water droplet and polymer-coated substrates decreased significantly compared to that on the original surface, further indicating the effective wetting mode transformation. The nanoporous polymer coating would open a new door for facile, rapid, safe, and larger scale fabrication of superhydrophobic surfaces on general substrates.Langmuir 08/2011; 27(20):12585-90. · 4.19 Impact Factor -
Article: Localized flexible integration of high-efficiency surface enhanced Raman scattering (SERS) monitors into microfluidic channels.
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ABSTRACT: We report here a facile approach for flexible integration of high efficiency surface enhanced Raman scattering (SERS) monitors in a continuous microfluidic channel. In our work, femtosecond laser direct writing was adopted for highly localizable and controllable fabrication of the SERS monitor through a multi-photon absorption (MPA) induced photoreduction of silver salt solution. The silver substrate could be shaped into designed patterns, and could be precisely located at the desired position of the microchannel bed, giving the feasibility for real-time detection during reactions. SEM and TEM images show that the silver substrates were composed of crystallized silver nanoplates with an average thickness of 50 nm. AFM results reveal that the substrates were about 600 nm in height and the surface was very rough. As representative tests for SERS detection, p-aminothiophenol (p-ATP) and flavin adenine dinucleotide (FAD) were chosen as probing molecules for microfluidic analysis at visible light (514.5 nm) excitation, exhibiting an enhancement factor of ~10(8). In addition, the combination of the SERS substrate with the microfluidic channel allows detection of inactive analytes through in situ microfluidic reactions.Lab on a Chip 08/2011; 11(19):3347-51. · 5.67 Impact Factor -
Conference Proceeding: Laser nanofabrication: Applications in micro-optics, micro-electronics, micromachines, and microfluidics
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ABSTRACT: Femtosecond laser micronanofabrication has been considered as a promising approach for complicated device fabrication in versatile fields due to its intrinsic three-dimensional (3D) prototyping capability and reasonably high fabrication accuracy up to tens of nanometers. However, the unique features haven't been fully demonstrated yet so far. Our research in the passed several years has been focused in exploring applications of delicate technology in micro-optics, microelectronics, micromachines and microfluidics. Significant progress has been achieved. Successful examples include but not limited to aspheric microlens arrays with 100% filling ratio and numerical aperture as high as 0.5, nonplanar metal nanowiring technology, flexible circuits of graphene, remotely magnetically controllable micromachine, and microfilter and microturbines for microfluidic channels. Details on the fabrication and characterizations on these devices will be presented.Lasers and Electro-Optics Europe (CLEO EUROPE/EQEC), 2011 Conference on and 12th European Quantum Electronics Conference; 06/2011 -
Article: Hierarchical self-assembly of CdTe quantum dots into hyperbranched nanobundles: suppression of biexciton Auger recombination.
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ABSTRACT: In this paper, we report a novel nanobundle structure formed by the hierarchical self-assembly of TGA-capped CdTe quantum dots. HR-TEM confirms the polycrystalline phase of the bundle structure, and that pristine quantum dots are the building units. The steady state absorption and luminescence properties of the pristine quantum dots can be well inherited by the nanobundles. In transient state observation, carrier quenching induced by Auger recombination is found to be remarkably suppressed. Electron delocalizing to close building units is considered to be the reason. Suppression of Auger recombination may earn much more time for charge separation, which makes the novel nanobundle structures suitable for the excellent donor material in solar cell applications.Nanoscale 05/2011; 3(7):2882-8. · 5.91 Impact Factor -
Article: Solvent response of polymers for micromachine manipulation.
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ABSTRACT: A novel solvent responsive polymer micromachine has been successfully fabricated by two-photon photopolymerization (TPP) of methacrylate-based photoresists. The moving part of the micromachine could be easily driven by interfacial solvent polarity induced swelling and shrinking of the photopolymer networks. Furthermore, the driving performance of the micromachine could be precisely modulated by varying the laser scanning step length during fabrication.Physical Chemistry Chemical Physics 02/2011; 13(11):4835-8. · 3.57 Impact Factor -
Article: Curvature-driven reversible in situ switching between pinned and roll-down superhydrophobic States for water droplet transportation.
Advanced Materials 01/2011; 23(4):545-9. · 13.88 Impact Factor -
Article: High performance magnetically controllable microturbines.
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ABSTRACT: Reported in this paper is two-photon photopolymerization (TPP) fabrication of magnetic microturbines with high surface smoothness towards microfluids mixing. As the key component of the magnetic photoresist, Fe(3)O(4) nanoparticles were carefully screened for homogeneous doping. In this work, oleic acid stabilized Fe(3)O(4) nanoparticles synthesized via high-temperature induced organic phase decomposition of an iron precursor show evident advantages in particle morphology. After modification with propoxylated trimethylolpropane triacrylate (PO(3)-TMPTA, a kind of cross-linker), the magnetic nanoparticles were homogeneously doped in acrylate-based photoresist for TPP fabrication of microstructures. Finally, a magnetic microturbine was successfully fabricated as an active mixing device for remote control of microfluids blending. The development of high quality magnetic photoresists would lead to high performance magnetically controllable microdevices for lab-on-a-chip (LOC) applications.Lab on a Chip 11/2010; 10(21):2902-5. · 5.67 Impact Factor -
Article: Flexible nanowiring of metal on nonplanar substrates by femtosecond-laser-induced electroless plating.
Small 08/2010; 6(16):1762-6. · 8.35 Impact Factor -
Article: Embellishment of microfluidic devices via femtosecond laser micronanofabrication for chip functionalization.
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ABSTRACT: This paper demonstrates the embellishment of existing microfluidic devices with integrated three dimensional (3D) micronanostructures via femtosecond laser micronanofabrication, which, for the first time, proves two-photon photopolymerization (TPP) to be a powerful technology for chip functionalization. As representative examples, microsieves with various pore shape and adjustable pore size were successfully fabricated inside a conventional glass-based microfluidic channel prepared by wet etching for microparticle separation. Moreover, a fish scale like microfilter was also fabricated and appointed as a one-way valve, which showed excellent performance as we expected. These results indicate that such embellishment of microfluidic devices is simple, low cost, flexible and easy to access. We believe that, combined with TPP, the application of lab-on-chip devices would be further extended.Lab on a Chip 08/2010; 10(15):1993-6. · 5.67 Impact Factor -
Article: Ferrofluids for fabrication of remotely controllable micro-nanomachines by two-photon polymerization.
Advanced Materials 08/2010; 22(29):3204-7. · 13.88 Impact Factor -
Article: Femtosecond laser direct patterning of sensing materials toward flexible integration of micronanosensors.
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ABSTRACT: Reported is femtosecond laser direct patterning of sensing materials toward flexible integration of micronanosensors (FIMS), meaning the capability to fabricate multiple functional sensors of smaller size on a nonflat surface of a substrate that is not limited to silicon. As a representative example, a photosensitive SnO(2) colloidal solution (sol) was developed, from which complex micronanostructures were written via a two-photon absorption process. After thermal decomposition of organic components, the patterned SnO(2) microsensors responded to relative humidity (RH) with a variation range of 5 orders of magnitude. FIMS would open a new door for miniaturization of micronanosensors expected in intelligent microsystems.Optics Letters 05/2010; 35(10):1695-7. · 3.40 Impact Factor -
Article: Mesoporous silica materials with an extremely high content of organic sulfonic groups and their comparable activities with that of concentrated sulfuric acid in catalytic esterification.
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ABSTRACT: Mesoporous silica materials (HS-JLU-20) with an extremely high content of mercaptopropyl groups have been successfully synthesized using fluorocarbon-hydrocarbon surfactant mixtures through a simple co-condensation approach of tetraethyl orthosilicate (TEOS) and (3-mercaptopropyl)trimethoxysilane (MPTS), which are characterized by X-ray diffraction (XRD), nitrogen adsorption and desorption isotherms, transmission electron microscopy (TEM), CHNS elemental analysis, thermogravimetry analysis (TGA), and (29)Si NMR spectroscopy. The results show that HS-JLU-20 samples with molar ratios of MPTS/(MPTS + TEOS) at 0.5-0.8 in the starting synthetic gels still show their mesostructures, while HS-SBA-15 with the molar ratio of MPTS/(MPTS + TEOS) at 0.50 completely loses its mesostructure in the absence of fluorocarbon surfactant. Possibly, fluorocarbon surfactant containing N(+) species with a positive charge could effectively interact with negatively charged mercapto groups in the synthesis of HS-JLU-20 materials, resulting in the formation of mesoporous silicas with good cross-linking of silica condensation even at an extremely high content of organic mercapto groups. More interestingly, after the treatment with hydrogen peroxide, HSO(3)-JLU-20 materials with an extremely high content of organic sulfonic groups exhibit comparable activity with liquid concentrated sulfuric acid in catalytic esterification of cyclohexanol with acetic acid.The Journal of Physical Chemistry B 08/2006; 110(29):14142-7. · 3.70 Impact Factor
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Institutions
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2010–2013
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Jilin University
- • State Key Laboratory on Integrated Optoelectronics
- • College of Electronic Science and Engineering
Jilin, Jilin Sheng, China
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