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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Improvement of External Quantum Efficiency of C <sub/>60</sub> /ZnPc Organic Photovoltaic Cells by Polymerization between C <sub/>60</sub> molecules
摘要： We have found that the external quantum efficiency of C60/ZnPc hetero-junction organic photovoltaics are improved by photo-induced polymerization between C60 molecules.
关键词： Fullerene,Organic Solar Cell,Energy Harvesting,Polymerization
更新于2025-09-16 10:30:52
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Improved performance of dye-sensitized solar cells upon sintering of a PEDOT cathode at various temperatures
摘要： Poly(3,4-ethylenedioxythiophene) (PEDOT) thin films have attracted considerable attention as cathodes for dye-sensitized solar cells (DSSCs) due to their air-stable, light-weight and conductive nature. To demonstrate their thermal stability as cathodes, PEDOT thin films coated via electrochemical polymerization on fluorine doped tin oxide (FTO) plates were sintered at different temperatures (50, 100, 150, 200, and 300 °C) for 1 h and a comparison was made with the as-prepared PEDOT thin films. We observed a negative temperature coefficient effect up to 200 °C along with lower surface roughness upon increasing the sintering temperature. Dye solar cells were fabricated using PEDOT thin films (sintered at different temperatures) and as-prepared PEDOT cathodes, and their respective performances were studied. The results showed increased efficiency with the increase in sintering temperatures of the cathode up to 200 °C (η = 4.33%) under the present experimental conditions. Cathodes sintered at 300 °C had poor electrochemical behavior and J–V performance, which may be due to polymer degradation.
关键词： cathodes,electrochemical polymerization,PEDOT,sintering,DSSCs
更新于2025-09-16 10:30:52
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Oxygen Tolerant PET-RAFT Facilitated 3D Printing of Polymeric Materials under Visible LEDs
摘要： Photopolymerization-based 3D printing process is typically conducted using free radical polymerization, which leads to fabrication of immutable materials. An alternative 3D printing of polymeric materials using trithiocarbonate (TTC) reversible addition-fragmentation chain transfer (RAFT) agents has always been a challenge for material and polymer scientists. Herein we report 3D printing of RAFT-based formulations that can be conducted fully open to air using standard digital light processing (DLP) 3D printer and under mild conditions of visible light at blue (λ max = 483 nm, 4.16 mW/cm2) or green (λ max = 532 nm, 0.48 mW/cm2) wavelength. Our approach is based on activation of TTC RAFT agents using eosin Y (EY) as a photoinduced electron-transfer (PET) catalyst in the presence of a reducing agent (triethylamine (TEA)), which facilitated oxygen tolerant 3D printing process via a reductive PET initiation mechanism. Re-activation of the TTCs present within the polymer networks enables post-printing monomer insertion into the outer layers of an already printed dormant object under a second RAFT process, which provides a pathway to design a more complex 3D printing. To our best knowledge, this is the first example of oxygen tolerant EY/TEA catalyzed PET-RAFT facilitated 3D printing of polymeric materials. We believe that our strategy is a significant step forward in the field of 3D printing.
关键词： Oxygen Tolerant,Trithiocarbonate,3D Printing,Visible Light-Induced PET-RAFT Polymerization,Digital Light Processing,Photoinduced Electron-Transfer
更新于2025-09-16 10:30:52
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Modeling and analysis for the position and posture errors of laser focal spot in large-scale fabrication via two photon polymerization
摘要： The position and posture errors of laser focal spot significantly affect the fabrication quality and functionality of microstructures in two photon polymerization, especially over a large area. These errors can be greatly reduced by using ultra-precision positioning device, such as piezoelectric stage and scanning galvanometer. However, the position and posture errors cannot be neglected in large-scale fabrication using large stroke linear stages which are necessary tools in most instances. In the present work, the relationship between the geometric errors of large stroke positioning platform and the position and posture of laser focal spot were revealed and modeled by homogeneous transformation matrix. Key errors affecting on the position and posture of focal spot were found out by sensitivity analysis and compensated during the construction of machine tool. Proof-of-concept experiments were performed in a millimeter-level (1 mm × 1 mm) fabrication of microfluidic whose surface was measured by an optical profiler. The measuring results showed that arithmetical mean height (Sa) and root mean square height (Sq) of the measured surface were less than 100 nm and maximum height (Sz) of the measured surface was less than 500 nm. The compensated machine tool demonstrated a high precise performance within a large continuous area. This work was expected to provide references for the rational layout of optical components in optical system or error compensation in laser process equipment over a large area.
关键词： Laser beam delivery,Position and posture error,Error analysis,Large-scale fabrication,Two photon polymerization
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Increasing Two-Photon Polymerization Fabrication Speed of 3D Structures for Cell Interaction Studies
摘要： Expanding cell studies and tissue engineering from a 2D platform to a 3D mimic of their natural environment demands fabrication methods capable of creating scaffolds covering large volumes with feature sizes down to a few μm. Two-photon polymerization (TPP) is a direct writing method capable of fabricating free-form 3D structures with sub-wavelength features and is therefore well-suited for template fabrication for cell motility and tissue engineering. We demonstrate 9 times increased fabrication speed for 3D periodic structures using a diffractive optical element (DOE) that creates 9 beamlets from one femtosecond laser beam. The parallelized method maintains fabrication quality and each beamlet is used for the fabrication of the base structures that form the periodic pattern. Two 3D designs were fabricated from bio-compatible SZ2080 polymer, where the distance between structures are accurately matching the distance between beamlets. Both of the fabricated structure arrays consists of 3x3 patterns with 9 individual structures in each pattern and covers an area of 450x450 μm. The first design contains unsupported interconnections between individual structures and field-of-views (FOV’s). The second design contains additional supporting structures that stabilize those interconnections between individual structures and FOV’s. For the first design high similarity is observed between the individual base structures inside each FOV, while at the stitching positions between different FOV’s discrepancies are observed leading to gaps in the overall periodic pattern. The gaps arise from contraction of the polymer material during the development process and subsequently drying process. It is related to large leapfrog movement of the stage system (>150 μm) between FOV’s. In the second design, additional support was added between individual one voxel thin structures to overcome this problem. Using this strategy, no gaps are observed and any remaining mismatch is less than 100 nm for stitching of structures. Additional studies were performed where HeLa-cells were incubated for 24 hours on both scaffolds and cell affinity is studied. We observe in both cases that HeLa-cells attach to wall and corner segments of the periodic designs and furthermore HeLa-cells are seen stretching the full length of the individual wall segments. In summary, we show that parallelization of the fabrication process has the potential to make TPP a fast method for large volume periodic 3D structure.
关键词： Two-photon polymerization,cell interaction studies,fabrication speed,diffractive optical element,3D structures
更新于2025-09-12 10:27:22
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Surface Carbon Shell-Functionalized ZrO2 as Nanofiller in Polymer Gel Electrolyte-Based Dye-Sensitized Solar Cells
摘要： We prepare dye-sensitized solar cells (DSSCs) fabricated with a poly (ethylene glycol) based polymer gel electrolytes (PGEs) incorporating surface carbon shell-functionalized ZrO2 nanoparticles (ZrO2-C) as nano?llers (NFs). ZrO2 are polymerized via atom transfer radical polymerization (ATRP) using poly (ethylene glycol) methyl ether methacrylate (POEM) as a sca?old to prepare the ZrO2-C through carbonization. The power conversion e?ciency of DSSC with 12 wt% ZrO2-C/PGEs is 5.6%, exceeding that with PGEs (4.4%). The enhanced e?ciency is attributed to Lewis acid-base interactions of ZrO2-C and poly (ethylene glycol), catalytic e?ect of the carbon shells of ZrO2-C, which results in reduced crystallinity, enhanced ion conductivity of electrolytes, decreased counterelectrode/electrolyte interfacial resistance, and improved charge transfer rate. These results demonstrate that ZrO2-C introduction to PGEs e?ectively improves the performance of DSSCs.
关键词： polymer gel electrolyte (PGE),zirconium dioxide (ZrO2),dye-sensitized solar cell (DSSC),nano?ller (NF),carbon,atom transfer radical polymerization (ATRP)
更新于2025-09-12 10:27:22
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Effective utilization of NIR wavelengths for photo-controlled polymerization - penetration through thick barriers and parallel solar syntheses
摘要： This contribution details an efficient and controlled photopolymerization regulated by far-red (λ = 680 nm) and NIR (λ = 780 and 850 nm) light in the presence of aluminum phthalocyanine and aluminum naphthalocyanine. Initiating radicals are generated by photosensitization of peroxides affording an effective strategy that provides controlled polymerizations of a variety of monomers with excellent living characteristics. Critically, long wavelength irradiation provides penetration through thick barriers, affording unprecedented rates of controlled polymerization that can open new and exciting applications. Furthermore, a more optimized approach to performing solar syntheses is presented. By combining the narrow Q-bands of these PCs with others possessing complementary absorptions, layered, independent polymerizations and organic transformations may be performed in parallel under a single broadband emission source such as sunlight.
关键词： Reversible-deactivation radical polymerization,Photochemistry,Photopolymerization,Solar synthesis,NIR
更新于2025-09-12 10:27:22
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High-Speed All-Optical Modulator Based on a Polymer Nanofiber Bragg Grating Printed by Femtosecond Laser
摘要： On-chip optical modulator for high-speed information processing system has been widely investigated by majority of researchers but the connection with the fiber system is a difficulty. The fiber-based optical modulator is a good solution to this problem. Fiber Bragg Grating has good potential to be used as an optical modulator because of its linear temperature response, narrow bandwidth, and compact structure. In this paper, a new fiber-integrated all-optical modulator has been realized based on a polymer nanofiber Bragg grating printed by femtosecond laser. This device exhibits a fast temporal response of 176 ns and a good linear modulation of -45.43 pm/mW. Moreover, its stability has also been studied. This work firstly employs Bragg resonance to realize a fiber-integrated all-optical modulator and paves the way toward realization of multifunctional lab-in-fiber devices.
关键词： polymer fiber,all-optical modulator,fiber Bragg grating,femtosecond laser micromachining,multi-photon polymerization
更新于2025-09-12 10:27:22
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Semiconductor Quantum Dots Are Efficient and Recyclable Photocatalysts for Aqueous PET-RAFT Polymerization
摘要： This Letter describes the use of CdSe quantum dots (QDs) as photocatalysts for photoinduced electron transfer reversible addition?fragmentation chain transfer (PET-RAFT) polymerization of a series of aqueous acrylamides and acrylates. The high colloidal solubility and photostability of these QDs allowed polymerization to occur with high efficiency (>90% conversion in 2.5 h), low dispersity (PDI < 1.1), and ultralow catalyst loading (<0.5 ppm). The use of protein concentrators enabled the removal of the photocatalyst from the polymer and monomer with tolerable metal contamination (8.41 ug/g). These isolated QDs could be recycled for four separate polymerizations without a significant decrease in efficiency. By changing the pore size of the protein concentrators, the QDs and polymer could be separated from the remaining monomer, allowing for the synthesis of block copolymers using a single batch of QDs with minimal purification steps and demonstrating the fidelity of chain ends.
关键词： block copolymers,CdSe quantum dots,photocatalysts,aqueous acrylamides,acrylates,protein concentrators,PET-RAFT polymerization
更新于2025-09-12 10:27:22
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Metal-free and photo-controlled fabrication of fluorinated anti-fouling film
摘要： We reported a new photo-controlled synthesis route to fabricate a fluorine-containing thin film for protecting the oxidation of indium tin oxide (ITO) and other derivatives such as the fluorine-doped tin oxide (FTO) coated glasses. A relatively inexpensive, color/metal-free organic phenothiazine-based photocatalyst for atom transfer radical polymerization (ATRP) was successfully adopted by an ultraviolet light source to modified substrates. The fluorine thin film had a contact angle (CA) with water of 105.1°, an advancing angle of 112.2°, and a receding angle of 84.6°; leading to a hydrophobic nature with self-cleaning and anti-fouling properties. Our fluorinated conductive glass shows an optical transmittance up to 80 – 90% in the visible wavelength range. This work demonstrates the great value in the anti-fouling of electronics that secures itself from chemical contaminations in outdoor environments and use at high temperature and chemical erosions.
关键词： Atom Transfer Radical Polymerization (ATRP),ITO,Photo-controlled,Polymer brushes,FTO
更新于2025-09-12 10:27:22