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Graphene-Incorporated Soft Capacitor for Mechanically-Adjustable Electro-Optic Modulators
摘要： In addition to ultra-high capacity and speed in data management, future communication networks require enhanced performance via system reconfigurability under limited resources. Extremely high-speed operation renders optical data managing devices as excellent candidates to hybridize with current electronic devices; however, they still need tunability for system reconfiguration in an integrated scheme. We demonstrate an efficient electro-optic (EO) modulator that is mechanically tunable on a multiple optical waveguide system functioned with a soft capacitor structure incorporating graphene and poly(methyl methacrylate) (PMMA). The flexible capacitor that generates optical signals by temporal light absorption depending on electrical signals can be mechanically detached and re-attached from and onto a rigid surface of the waveguide. It provides either the on or off state of the modulating operation, and enables switching of the working waveguides following the reconfigured data routes. Quality-controlled graphene mainly provides the EO operation, and PMMA plays an important role as both the flexible dielectric layer in the capacitor and the passivation layer for graphene protection. The modulation effects of the manually prepared graphene-PMMA capacitor mechanically adjusted onto a side-polished optical fiber (D-shaped fiber) are investigated in terms of the extinction ratio (ER) of the transmitting light and the operational bandwidth. We successfully display an ER of the modulator up to 19.8 dB with a voltage control ranging from -50 V to 50 V. Its stable operation is verified with a modulation speed up to 2.5 MHz.
关键词： electro-optic modulator,mechanical tuning,graphene,tunable modulator,soft material
更新于2025-11-28 14:24:03
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Refractive Index Measurement of Lithium Ion Battery Electrolyte with Etched Surface Cladding Waveguide Bragg Gratings and Cell Electrode State Monitoring by Optical Strain Sensors
摘要： In this scientific publication, a new sensor approach for status monitoring, such as state of charge and state of health, of lithium ion batteries by using special Bragg gratings inscribed into standard optical glass fibers is presented. In addition to well-known core gratings, embedded into the anode of 5 Ah lithium ion pouch cells as a strain monitoring unit, the manufacturing of a surface cladding waveguide Bragg grating sensor incorporated into the cell’s separator, that is sensitive to changes of the refractive index of the surrounding medium, is demonstrated. On the basis of the experiments carried out, characteristics of the cell behavior during standard cyclization and recognizable marks in subsequent post-mortem analyses of the cell components are shown. No negative influence on the cell performance due to the integrated sensors have been observed; however, the results show a clear correlation between fading cell capacity and changes of the interior optical signals. Additionally, with the novel photonic sensor, variations in the electrolyte characteristics are determinable as the refractive index of the solution changes at different molar compositions. Furthermore, with the manufactured battery cells, abuse tests by overcharging were conducted, and it was thereby demonstrated how internal battery sensors can derive additional information beyond conventional battery management systems to feasibly prevent catastrophic cell failures. The result of the research work is an early stage photonic sensor that combines chemical, mechanical and thermal information from inside the cell for an enhanced battery status analysis.
关键词： lithium ion,battery aging,cladding waveguide,battery electrolyte,optical sensors,battery safety,fiber Bragg grating,electrode active material,status monitoring
更新于2025-11-28 14:23:57
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Multifunctional Thermosensitive Liposomes Based on Natural Phase Change Material: Near-Infrared Light-Triggered Drug Release and Multimodal Imaging Guided Cancer Combination Therapy
摘要： Multifunctional theranostic nanoplatforms (NPs) in response to environment stimulations for on-demand drug release are highly desirable. Herein, the near-infrared (NIR)-absorbing dye, indocyanine green (ICG) and the antitumor drug, doxorubicin (DOX) were efficiently co-encapsulated into the thermosensitive liposomes based on natural phase change material (PCM). Folate and conjugated gadolinium chelate-modified liposome shells enhance active targeting and magnetic resonance (MR) performance of the NPs while maintaining the size of the NPs. The ICG/DOX loaded and gadolinium chelates conjugated temperature-sensitive liposomes nanoplatforms (ID@TSL-Gd NPs) exhibited NIR-triggered drug release and prominent chemo-, photothermal, photodynamic therapy properties. With the co-encapsulated ICG, DOX and the conjugated gadolinium chelates, the ID@TSL-Gd NPs can be used for triple-modal imaging (fluorescence/photoacoustic/magnetic resonance imaging, FL/PAI/MRI) guided combination tumor therapy (chemotherapy, photothermotherapy and photodynamic therapy, Chemo/PTT/PDT). After tail vein injection, the ID@TSL-Gd NPs accumulated effectively in subcutaneous HeLa tumor of mice. The tumor was effectively suppressed by accurate imaging guided NIR triggered phototherapy and chemotherapy, and no tumor regression and side effects were observed. In summary, the prepared ID@TSL-Gd NPs achieved multimodal imaging-guided cancer combination therapy, providing a promising platform for improving diagnosis and treatment of cancer.
关键词： Multimodal imaging,Liposomes,Thermosensitive,Combination therapy,Phase change material
更新于2025-11-21 11:08:12
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Superior light harnessing and charge injection kinetics utilizing mirror-like nano cuboidal ceria coupled with reduced graphene oxide in zinc oxide nanoparticle based photovoltaics
摘要： Efficiency in nanoparticle based photovoltaics is limited by optical transparency, light absorption as well as detrimental back transfer of electron at the hetero-interfaces. Three dimensional (3D) micro/nanostructures with excellent light scattering properties play pivotal role in light harvesting efficiency in DSSCs. Present study deals with the design and development of ternary hybrid photoanode utilizing high quality mirror like nano-cuboidal ceria (CeO2 NC) and 2D- reduced graphene oxide (RGO) sheets in conjunction with ZnO nanoparticle. A ～6% power conversion efficiency has been achieved for photoanode with optimized CeO2 NC loaded with 1 wt% RGO into ZnO NP. CeO2 NC owing to its size and high quality mirror like facets provides a better light harvesting by multiple interactions of incident photon with the absorber as revealed by UV–Vis diffused reflectance and IPCE analysis. 2D- RGO is proposed to act as an electron sink and provides faster electron transport pathway. Inclusion of 2D- RGO sheets yields a better charge injection kinetics (keinj ～ 2.3 × 108 s?1 for ternary, 1.1 × 108 s?1 for reference device) and collection at FTO as well as elevated recombination resistance (Rrec) and photo-induced electron life time (τe), unveiled by Electrochemical Impedance Spectroscopic (EIS) analysis corroborates a reduced reverse tunneling of photo-injected electron at ZnO/sensitizer/redox couple interface.
关键词： Diffusion,Mirror-like,Light scattering material,Reduced graphene oxide,Electrochemical impedance spectroscopy,Nano cuboidal
更新于2025-11-21 11:01:37
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Demonstration of Photovoltaic Action and Enhanced Stability from a Quasi-Two-Dimensional Hybrid Organic–Inorganic Copper–Halide Material Incorporating Divalent Organic Groups
摘要： Commercialization of solar cells based on photoactive lead–halide perovskites is in-part limited by their toxicity and instability. In this study, new and related copper–halide hybrid organic–inorganic materials containing dicationic 1,6-hexanediammonium (+H3N-C6H12-NH3+) demonstrated superior stability to heat and moisture in comparison to the analogous material containing monocationic 1-propylammonium (C3H7-NH3+) in twice the stoichiometry. Electronic absorption spectra taken of the materials were consistent with an indirect optical bandgap of ~1.8 eV, making them well-suited for application as the photoactive layer in the top cell of a tandem solar cell with silicon. The best-performing single-junction solar cells containing the dicationic material as the photoactive layer exhibited an open-circuit photovoltage in excess of 400 mV and a short-circuit photocurrent density of ~30 μA/cm2. These values are similar to those reported for state-of-the-art copper–halide hybrid organic–inorganic materials containing organic monocations and motivate further research on this class of materials.
关键词： photovoltaic,two-dimensional material,dications,solar cell,copper halide,hybrid material,stability,perovskite
更新于2025-11-19 16:56:42
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Perovskite solar cells based on polyaniline derivatives as hole transport materials
摘要： Perovskite solar cells (PSC) have been extensively studied over the past few years in both academia and industry. Despite their appeal as a low cost and ease processing PV-technology, PSC still rely on materials that are expensive, turning the large-scale production more challenging. In this work, polyaniline (PAni) and its derivative poly(o-methoxyaniline) are employed as hole transport material (HTM) in PSC, replacing the most explored HTM, spiro-OMeTAD. These very well established conducting polymers are doped with 4-dodecylbenzenesulfonic acid (DBSA) to enhance their conductivity. The correlation between the performance of the solar cells using doped and undoped conducting polymers and different metallic contacts are also evaluated. The best power conversion efficiency was 10.05% using doped PAni-DBSA with Au as contact, which is similar to the performance exhibited by our standard device using Spiro-OMeTAD as HTM.
关键词： hole transport material,perovskite solar cells,polyaniline
更新于2025-11-19 16:56:42
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Adsorption and Photocatalytic Decomposition of Gaseous 2-Propanol Using TiO2-Coated Porous Glass Fiber Cloth
摘要： Combinations of TiO2 photocatalysts and various adsorbents have been extensively investigated for eliminating volatile organic compounds (VOCs) at low concentrations. Herein, TiO2 and porous glass cloth composites were prepared by acid leaching and subsequent TiO2 dip-coating of the electrically applied glass (E-glass) cloth, and its adsorption and photocatalytic ability were investigated. Acid leaching increased the specific surface area of the E-glass cloth from 1 to 430 m2/g while maintaining sufficient mechanical strength for supporting TiO2. Further, the specific surface area remained large (290 m2/g) after TiO2 coating. In the photocatalytic decomposition of gaseous 2-propanol, the TiO2-coated porous glass cloth exhibited higher adsorption and photocatalytic decomposition ability than those exhibited by the TiO2-coated, non-porous glass cloth. The porous composite limited desorption of acetone, which is a decomposition intermediate of 2-propanol, until 2-propanol was completely decomposed to CO2. The CO2 generation rate was affected by the temperature condition (15 or 35 °C) and the water content (2 or 18 mg/L); the latter also influenced 2-propanol adsorption in photocatalytic decomposition. Both the conditions may change the diffusion and adsorption behavior of 2-propanol in the porous composite. As demonstrated by its high adsorption and photocatalytic ability, the composite (TiO2 and porous glass cloth) effectively eliminates VOCs, while decreasing the emission of harmful intermediates.
关键词： air purification,composite,adsorption,microporous material,porous glass,photocatalyst,TiO2
更新于2025-11-19 16:51:07
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Broad-Spectrum Tunable Photoluminescent Material Based on Cascade Fluorescence Resonance Energy Transfer between Three Fluorophores Encapsulated within the Self-Assembled Surfactant Systems
摘要： A broad spectrum tunable photoluminescent material with dual encryption based on a two-step Fluorescence Resonance Energy Transfer (FRET) between Pyrene (Py), Coumarin480 (Cou480) and Rhodamine6G (R6G) in micelles of SDS and bmimDS is presented. The phenomenon is achievable due to the encapsulation of the fluorophores within these micelles. The transfer of energy as FRET between the pair Py and Cou480 showed ON at 336 nm and OFF at 402 nm in contrast to the FRET observed between the pair Cou480 and R6G that showed ON at 402nm and OFF at 336 nm. However, the transfer of energy as FRET occurs from Py to R6G in the presence of Cou480 when excited at 336 nm, thereby making it a chain of three fluorophores with Cou480 acting as a relay fluorophore receiving energy from Py and transferring it to R6G. The different FRET scenarios between the three fluorophores in micelles provide a window for the generation of a matrix of colors, which occupies a significant 2D area in the chromaticity diagram, having potential applications in security printing. The different fluorophoric ratios generate different colors based on their individual photonic emissions and the FRET processes taking place between them. Writing tests were carried out using varied ratios of the fluorophores in the micellar systems producing different colored outputs under the UV light with insignificant visibility under the white light. We envision that this as-discovered three fluorophoric FRET system could form the basis for the future development of multi-FRET light-harvesting devices and anti-counterfeiting security inks based on much simpler non-covalent interaction aided encapsulation of the fluorophores within the self-assembled soft systems.
关键词： micelles,security printing,Rhodamine6G (R6G),SDS,Pyrene (Py),Coumarin480 (Cou480),bmimDS,Fluorescence Resonance Energy Transfer (FRET),photoluminescent material
更新于2025-11-19 16:46:39
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Facile synthesis of extended TPA-quinazolinone derivatives and the nonlinear optical properties
摘要： In this work, four new quinazolinone(QZ)-based compounds containing triphenylamine (TPA) moiety have been synthesized, defined as QZC, QZC-1, QZC-2, QZC-3, for the application of third-order nonlinear optical (NLO) responses. A new design of two-step synthesis has been put forward, the first step is Ullmann reaction with QZ, and the second is connecting QZ and the substituted triphenylamines (TPAs) through a Suzuki cross-coupling reaction to afford the target products. Electrochemical measurement data indicated that the tuning of the HOMO and LUMO energy levels can be easily achieved by introducing and modifying the donor moiety. The NLO properties were evaluated by the Z-scan technique which showed that introduction of a benzene ring as a π bridge could reduce the transmission energy of electrons from a ground state to an excited state, and the added methoxy in TPA moiety could promote the ICT, and improve the third-order NLO properties of molecules. Theoretical calculations matched well with the electrochemical information and NLO information. The results suggest that the materials based on QZ have potential applications in integrated NLO devices.
关键词： Fluorescence,photophysical property,Extended Quinazolinone derivative,third-order NLO material,Z-scan technology
更新于2025-11-19 16:46:39
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Alcohol-Guided Growth of Two-Dimensional Narrow-Band Red-Emitting K2TiF6:Mn4+ for White Light-Emitting Diodes
摘要： The use of red phosphors with low light-scattering loss could improve the luminous efficacy and color rendering of white light-emitting diodes (LEDs). Thus, the discovery of such phosphors is highly desired. In this work, high-efficiency two-dimensional red-emitting K2TiF6:Mn4+ (KTFM) were synthesized via an alcohol-assisted coprecipitation route. The synergistic effects of 1-propanol and hydrofluoric acid (HF) on the growth of KTFM microsheets (MSs) were studied through the first-principles calculations, which revealed that 1-propanol promoted the growth of KTFM MSs by preferentially adsorbing on the H-terminated K2TiF6 (001) surface. The photoluminescence quantum efficiency (QE) of Mn4+-activated K2TiF6 MSs was highly related to their size and thickness. The morphology-optimal KTFM MSs presented high internal QE (> 90 %), external QE (> 71%), and thermal quenching temperature (102% at 150 °C relative to that at 25 °C). A prototype phosphor-converted LED with KTFM as the red-emitting component showed an excellent color rendition (Ra = 91, R9 = 79) and high luminous efficacy (LE =156 lm/w).
关键词： light emitting diode,two-dimensional material,Narrow band,K2TiF6:Mn4+,backlight,red emission
更新于2025-11-14 17:04:02