- 标题
- 摘要
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- 实验方案
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Electrospun carbon nanofibers decorated with Pt-Ni2P nanoparticles as high efficiency counter electrode for dye-sensitized solar cells
摘要： Carbon nanofibers (CNs) supported by Pt and Ni2P nanoparticles (Pt-Ni2P/CNs) are successfully synthesized and explored as counter electrodes for dye-sensitized solar cells (DSSCs) for the first time. Pt and Ni2P nanoparticles are prepared by stabilization and carbonization of electrospun nanofibers, and subsequently controllable Pt and Ni2P nanoparticles are grown on surface of CNs obtained through redox reaction. A series of electrochemical measurements analysis confirm that the Pt-Ni2P/CNs composite have simultaneously superior electrocatalytic activity and enhanced electrical conductivity compared with those of individual CNs and Pt. Accordingly, DSSCs using the composite Pt-Ni2P/CNs as a counter electrode exhibit a excellent photovoltaic performance (power conversion efficiency of 9.11%), which is much higher than conventional Pt/CNs counter electrode (power conversion efficiency of 8.35%), owing to the collective effect of the high electrical conductivity originated from carbon nanofibers and superior electrocatalytic activity arising from Pt/CNs nanoparticles.
关键词： counter electrode,electrospun,dye-sensitized solar cells,Pt and Ni2P nanoparticles,redox reaction
更新于2025-11-14 15:27:09
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Noninvasive biodegradable nanoparticles-in-nanofibers single-dose ocular insert: <i>in vitro</i> , <i>ex vivo</i> and <i>in vivo</i> evaluation
摘要： Aim: This study involves, for the first time, the development of mucoadhesive biodegradable polymeric-multilayered nanoparticles-in-nanofibers (NPs-in-NFs) matrix as an innovative single-dose noninvasive ocular-insert that could substitute conventional ocular dosage-forms. Materials & methods: Azithromycin-loaded poly(lactic-co-glycolic acid) copolymer/pluronic NPs were developed then incorporated into electrospun polyvinylpyrrolidone NFs, and tested for their efficient treatment of ocular bacterial infection. Results: Release and permeation studies proved the ability of the insert to control drug release over 10 days. Conclusion: The incorporation of NPs into NFs achieved several other benefits like increasing ocular residence and contact time with conjunctival tissue, accurate dose delivery, sustaining drug release with constant rate, reducing frequency of administration, improving bioavailability along with decreasing incidence of visual and systemic side effects.
关键词： nanofibers,electrospun,bacterial infection,single-dose,ocular,azithromycin
更新于2025-09-23 15:23:52
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Synthesis of electrospun nanofibrous structures with controlled optical and electrical properties
摘要： In this study, the optical and electrical influences of 2D graphene flakes in electrospun polycaprolactone (PCL) fibers were observed. Graphene nanoplatelets were added in different concentrations into the PCL solution, and then, using the electrospinning technique, fibers were built from that solution. Three samples were prepared with different graphene concentrations of 0% w/w, 0.5% w/w, and 2.0% w/w. From all three samples, fibers were prepared and tests were conducted for the identification of the properties of fibers. An optical spectroscopy test was performed to identify the optical behavior of the fibers. Scanning electron microscopy tests were conducted for the morphological characterization of the fibers. For the comparison of the electrical conductivity of the three samples, electrical tests were also conducted. In addition, Raman spectroscopy was conducted to characterize the graphene and PCL. This study shows that using graphene can change the properties of fibers, for example, as the graphene content increases, the fiber diameter also increases. Also, by varying the 2D graphene concentration, both electrical and optical properties can be tuned; this can be utilized in the synthesis of nanosensing surfaces and structures.
关键词： polycaprolactone,graphene nanoplatelets,optical properties,electrical properties,electrospun nanofibrous structures
更新于2025-09-23 15:19:57
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Ag-fiber/graphene hybrid electrodes for highly flexible and transparent optoelectronic devices
摘要： Transparent conducting electrodes (TCEs) have attracted considerable attention towards the development of flexible optoelectronic devices. In this study, mixed-dimensional TCEs are fabricated based on the two-dimensional graphene and one-dimensional electrospun metal fiber that can address the shortcomings of each electrode. In comparison with other TCEs, the Ag fiber/graphene hybrid electrodes exhibited a highly stable morphology (67% lower peak-to-valley ratio), low sheet resistance (approximately 11 Ω/sq), high transmittance (approximately 94%), high oxidation stability with excellent flexibility, and outstanding chemical stability. The multiple functionalities of the transparent and flexible hybrid structure highlight its potential for applications in emerging electronics and highly stable optoelectronics.
关键词： transparent conducting electrodes,Ag-fiber/graphene hybrid electrodes,flexible optoelectronic devices,graphene,electrospun metal fiber
更新于2025-09-23 15:19:57
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Grafted PEO polymeric ionic liquid nanocomposite electrospun membrane for efficient and stable dye sensitized solar cell
摘要： An innovative polymeric ionic liquid (PIL) was synthesized by covalently grafting vinyl imidazolium iodide and methyl methacrylate onto poly (ethylene oxide) (PEO). Synthesised tungsten oxide nanoparticles (WO3NPs) were incorporated into the PIL solution and a polymer nanocomposite fibrous membrane (PVIM-W) was fabricated by electrospinning. This was used as a functional electrolyte for quasi solid state dye sensitized solar cell ((QSS-DSSC). The structure and morphology of the membranes and its physical characteristics as electrolytes were studied. The SEM images showed formation of uniform and beadless nanofibers. Photovoltaic and electrochemical effects of all the electrolytes have been examined. PVIM-W membrane exhibited superior power conversion efficiency (η) of 7.2% and better stability (up to 94.4% of its initial conversion efficiency after 500 h) when compared to the cell with the liquid electrolyte (η= 6.85%) and the ungrafted PEO membrane. This novel PVIM-W membrane based electrolyte shows great prospect for development of efficient and stable QSS-DSSC.
关键词： polymeric ionic liquid,poly (ethylene oxide),Dye sensitized solar cell,electrolyte,electrospun membrane
更新于2025-09-19 17:13:59
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Random laser in dye-doped electrospun nanofibers: Study of laser mode dynamics via temporal mapping of emission spectra using Pearson's correlation
摘要： The development of optically active flexible nanostructures has been pursued in the last years owing to their potential application in photonic devices. Herein, we report a random laser architecture based on a flexible Rhodamine B-doped PMMA nanofibers produced via electrospinning technique with 1% and 5% (w/w) of dye. The lower concentrated sample provided only incoherent emission due to the low absorption mean free path. The most concentrated one provided both coherent and incoherent random laser emission depending on the position of the sample the excitation took place. Pearson’s correlation coefficient maps showed a clear correspondence with the already established mode locking transition in random laser. A temporal mapping of successive emission spectra was performed, which provided qualitative information about mode competition dynamic when applied to coherent emission spectra and a highly sensitive way of tracking line widening and red/blueshift in incoherent random laser emission spectra. The developed system can be further employed to design novel miniaturized chemical and temperature sensors.
关键词： Electrospun nanofibers,Random laser,Mode correlation,Temporal dynamics
更新于2025-09-19 17:13:59
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Bulk and localized plasmonic heating in nanogold doped polymers
摘要： Colloidal gold (Auc) nanoparticles (GNPs) and nanorods (GNRs) were incorporated into polymer blend ?lms and electrospun ?bers to utilize the nanoparticle plasmonic response for localized heating of the polymer. In this work, mathematical modeling was used to describe the GNP distribution and heat/melt pro?le surrounding each GNP in the polymer blend, demonstrating that a bulk temperature change of only 0.2 °C results in a 20-nm-diameter melted polymer sphere around the GNP. In addition, it was shown that by reducing the radius of polymer material around the GNP through the use of electrospinning ?bers in place of thin ?lm deposition, heating of the bulk material increased by 72%. Bulk heating of polymer blend ?lms containing either GNPs or GNRs was mapped using an infrared camera system with light-emitting diodes (LEDs) at 530 and 810 nm. The change in temperature observed in the thin ?lms was used to calculate the photo-thermal energy conversion ef?ciency of the respective nanogold doped polymer thin ?lms. Signi?cantly, GNR-doped ?lm ef?ciencies recorded were up to 6.6 times (558.6% increase) that of the polymer blend-only ?lm when interrogated at 810 nm, while the GNP-doped ?lm ef?ciency increased by 1.8 times (75.7% increase) under the 530 nm LED.
关键词： nanogold doped polymers,photothermal energy conversion,electrospun fibers,plasmonic heating
更新于2025-09-16 10:30:52
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Plasmonic Response of Light-Activated, Nano-Gold Doped Polymers
摘要： Incorporation of metallic nanoparticles (NPs) in polymer matrix has been used to enhance and control dissolution and release of drugs, for targeted drug delivery, as antimicrobial agents, localized heat sources, and for unique optoelectronic applications. Gold NPs in particular exhibit a plasmonic response that has been utilized for photothermal energy conversion. Because plasmonic nanoparticles typically exhibit a plasmon resonance frequency similar to the visible light spectrum, they present as good candidates for direct photothermal conversion with enhanced solar thermal efficiency in these wavelengths. In our work, we have incorporated ~3-nm-diameter colloidal gold (Auc) NPs into electrospun polyethylene glycol (PEG) fibers to utilize the nanoparticle plasmonic response for localized heating and melting of the polymer to release medical treatment. Auc and Auc in PEG (PEG+Auc) both exhibited a minimum reflectivity at 522 nm or approximately green wavelengths of light under ultraviolet-visible (UV-Vis) spectroscopy. PEG+Auc ES fibers revealed a blue shift in minimum reflectivity at 504 nm. UV-Vis spectra were used to calculate the theoretical efficiency enhancement of PEG+Auc versus PEG alone, finding an approximate increase of 10 % under broad spectrum white light interrogation, and ~14 % when illuminated with green light. Auc enhanced polymers were ES directly onto resistance temperature detectors and interrogated with green laser light so that temperature change could be recorded. Results showed a maximum increase of 8.9 °C. To further understand how gold nanomaterials effect the complex optical properties of our materials, spectroscopic ellipsometry was used. Using spectroscopic ellipsometry and modeling with CompleteEASE? software, the complex optical constants of our materials were determined. The complex optical constant n (index of refraction) provided us with optical density properties related to light wavelength divided by velocity, and k (extinction coefficient) was used to show the absorptive properties of the materials.
关键词： spectroscopic ellipsometry,photothermal energy conversion,polyethylene glycol,metallic nanoparticles,plasmonic response,UV-Vis spectroscopy,gold NPs,electrospun fibers
更新于2025-09-16 10:30:52
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Multiple Scattering from Electrospun Nanofibers with Embedded Silver Nanoparticles of Tunable Shape for Random Lasers and White-Light-Emitting Diodes
摘要： Random lasers (RLs) are convenient, tunable, and widely applicable. However, the influence of fluorescence lifetime on the scattering and nanofiber distribution of nanofibers with various shapes of silver nanoparticles (Ag NPs) embedded within is unclear. We prepared polyvinyl alcohol (PVA) nanofibers with Ag NPs through electrospinning (ES) and pyrromethene 597 dye doping. We determined the influences of the particles on scattering enhancement and localized surface plasmon resonance (LSPR) in RLs. The distinct scattering rates and LSPR can be used to control optical properties for sensing devices and other applications. Compared with traditional films, the threshold of the nanofibers with Ag NPs is 35% lower. In addition to improved matching between the LSPR and emission spectra, enhanced coupling of the electric field with nonradiative energy amplifies the radiative emission. Furthermore, the luminescence lifetime shortened by increasing the scattering rate. An excessive scattering rate may accelerate radiative recombination and convert some recombination into nonradiative recombination to produce a more sensitive device. Finally, we applied the prepared nanofibers to a backlight display and fabricated a white-light-emitting diode (LED) with a distinct thickness of nanofibers. The fabricated device is suitable for application in other LEDs and RL devices.
关键词： light scattering,silver nanoparticles,plasmonic,electrospun fibers,random lasers
更新于2025-09-12 10:27:22
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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) - Random Laser Action from Electrospun Polymeric Nanofibers Doped Either with Organic Dye or Semiconductor Nanoprisms
摘要： The search for light sources with targeted characteristics motivates the work of a large part of the photonics community. One topical subject in this area is the study of Random Lasers (RLs), which use as feedback mechanism the light scattering in a random medium instead of a Fabry-Perot cavity. A large variety of RLs and a diversity of applications have already been demonstrated. Of interest in many applications are RLs based on flexible hosts, which act not only as mechanical support, but also as scattering agent. Such host can be obtained, for example, by electrospinning fibers made by environment-friendly materials. In this work, we report on a technique to produce a system composed by electrospun acetate ester of cellulose nanofibers (AEC-NFs) containing poly(ethylene oxide) – PEO (10% or 20% wt. - known to improve the mechanical properties of AEC-NFs), which presence originates a double-peaked diameter distribution centred around 120 nm and 600 nm. RL experiments were made with either Rhodamine 6G (Rh6G, 2 mM) or 40% wt. ZnO nanoprisms (NPs), that act as gain media. By varying the PEO amount in the AEC-NFs we investigate how the structures with smaller diameters act as scatterers for obtaining RL emission. Raman spectroscopy was performed in order to assure that PEO has been incorporated to the AEC-NFs in the desired amount.
关键词： poly(ethylene oxide),Rhodamine 6G,Random Lasers,ZnO nanoprisms,electrospun nanofibers
更新于2025-09-11 14:15:04