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MECHANICAL AND OPTICAL INVESTIGATION OF LASER WELDED STRUCTURAL STEEL - POLY(METHYL-METHACRYLATE) HYBRID JOINT STRUCTURES
摘要： Modern welding processes that can easily be automated (such as friction stir welding, laser welding and ultrasonic welding) are gaining popularity in joining metal-polymer hybrid structures. This ?eld of science is intensively studied around the globe, as a dependable, productive joining method that directly produces structurally sound joints between a metal and a polymer structure could unleash unforeseen possibilities in the vehicle industry. In our experiments, we manufactured hybrid steel-poly(methyl-methacrylate) (PMMA) joints with laser welding, using the 2p design of experiment method. We measured the e?ect of cellulose reinforcing ?bres (in varying weight percentages) on the transparency and weldability of the PMMA material and the e?ect of welding parameters on the mechanical properties of the joints. We also examined the vicinity of the welded seam with scanning electron microscopy.
关键词： Laser welding,poly(methyl-methacrylate),metal-polymer hybrid structures
更新于2025-09-23 15:19:57
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Photophysical Properties of Multilayer Graphenea??Quantum Dots Hybrid Structures
摘要： Photoelectrical and photoluminescent properties of multilayer graphene (MLG)–quantum dots (QD) hybrid structures have been studied. It has been shown that the average rate of transfer from QDs to the MLG can be estimated via photoinduced processes on the QDs’ surfaces. A monolayer of CdSe QDs can double the photoresponse amplitude of multilayer graphene, without influencing its characteristic photoresponse time. It has been found that efficient charge or energy transfer from QDs to MLG with a rate higher than 3 × 108 s?1 strongly inhibits photoinduced processes on the QD surfaces and provides photostability for QD-based structures.
关键词： photophysical properties,CdSe–ZnS quantum dots,hybrid structures,photoelectrical properties,multilayered graphene,photoactivation
更新于2025-09-23 15:19:57
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Delayed Charge Recombination by Opena??Shell Organics: Its Application in Achieving Superb Photodetectors with Broadband (400a??1160 nm) Ultrahigh Sensitivity and Stability
摘要： Monolayer transition-metal dichalcogenides have inspired worldwide efforts in optoelectronic devices but real applications are hindered with their reduced optical absorption due to their atomically ultrathin signature. In this study, by utilizing their biradical nature such as excellent absorption coefficient, broad bandwidth from the ultraviolet to near-infrared region, and small triplet–singlet energy gap, a series of helicene 5,14-diaryldiindeno[2,1-f:1′,2′-j]picene (DDP) derivatives (1ab, 1ac, and 1bb) are integrated with monolayer MoS2 for extraordinary photodetector performance and outstanding stability. Via comprehensive time-resolved studies, the interfacial charge-transfer process from the DDPs to the MoS2 layer is evidenced by the stabilized exciton property of the organics (1ac)/MoS2 heterostructure. Significantly, the 1ac/MoS2 photodetector exhibits an ultrahigh photoresponsivity of 5 × 107 A W?1 and a fast response speed of 45 ms due to the highly efficient photoexcited carrier separation and the matched type-II energy band alignment. The biradical 1ac/MoS2 hybrid photodetector shows no sign of degradation after one-month operation. The results pave a new avenue for biradical based high-performance and super-broadband optoelectronic devices.
关键词： photodetectors,hybrid structures,MoS2,biradical organic molecules,transition metal dichalcogenides
更新于2025-09-23 15:19:57
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Nanohybrid Structures Based on Plasmonic or Fluorescent Nanoparticles and Retinal-Containing Proteins
摘要： Rhodopsins are light-sensitive membrane proteins enabling transmembrane charge separation (proton pump) on absorption of a light quantum. Bacteriorhodopsin (BR) is a transmembrane protein from halophilic bacteria that belongs to the rhodopsin family. Potential applications of BR are considered so promising that the number of studies devoted to the use of BR itself, its mutant variants, as well as hybrid materials containing BR, in various areas grows steadily. Formation of hybrid structures combining BR with nanoparticles is an essential step in promotion of BR-based devices. However, rapid progress, continuous emergence of new data, as well as challenges of analyzing the entire data require regular reviews of the achievements in this area. This review is devoted to the issues of formation of materials based on hybrids of BR with fluorescent semiconductor nanocrystals (quantum dots) and with noble metal (silver, gold) plasmonic nanoparticles. Recent data on formation of thin (mono-) and thick (multi-) layers from materials containing BR and BR/nanoparticle hybrids are presented.
关键词： hybrid structures,quantum dots,bacteriorhodopsin,supramolecular systems,SERS,plasmon nanoparticles,Raman scattering
更新于2025-09-23 15:19:57
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Fabrication and characterization of PSi/nanometal hybrid structures by laser for CO gas sensor
摘要： Mesoporous silicon (mesoPSi) layers fabricated by the photoelectrochemical etching (PECE) method in hydrofluoric acid (HF) are active as carbon monoxide gas sensors. The modified porous silicon (PSi) can be used with noble metals to manufacture an effective gas sensor. Embedded gold, platinum, and palladium nanoparticles Au, Pt, and Pd-NPs could modify the surface morphology of mesoPSi and form mesoPSi/AuPtPd-NPs hybrid structures through a simple and dipping process in fixed salt concentrations. The morphology of the hybrid structures has been studied using scanning electron microscopy and X-ray diffraction. The prepared gas sensor has measured the electrical characteristics at room temperature. Shape, nanoparticle size, and specific surface area strongly influenced the current–voltage characteristics. The results show that Au, Pd, and Pt-NPs sizes prepared by the dipping process for mesopore-like structures were in the range from 0.64 to 7.53 nm. Besides, considerable improvements in the response, recovery times and sensitivity of gas sensor were noticed when decreasing the incorporated Au, Pd, and Pt-NPs to the mesoPSi matrix.
关键词： SEM,Gas sensing,Photoelectrochemical,AuPtPd-NPs hybrid structures,MesoPSi
更新于2025-09-19 17:13:59
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The Influence of Photoinduced Processes on a Quantum Dot Surface on the Electron Transfer Efficiency in TiO2 Nanoparticle/Quantum Dot Structures
摘要： The influence of photoinduced processes occurring on the surfaces of CdSe/ZnS quantum dots is considered in relation to the functional characteristics of hybrid TiO2 nanostructure/quantum dot systems. Preirradiation of quantum dots is shown to achieve a threefold increase in electron transfer efficiency within these structures. Photoinduced processes are found to impact both the efficiency of nonradiative phenomena in quantum dots and the electron transfer in the indicated systems.
关键词： photoinduced processes onto quantum dots,photoinduced electron transfer,photoactivation,semiconducting quantum dots,hybrid structures,titanium dioxide nanoparticles
更新于2025-09-16 10:30:52
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Tuning the photoinduced charge transfer from CdTe quantum dots to ZnO nanofilms through Ga doping
摘要： Tuning the charge transfer rate between quantum dots (QDs) and metal oxide (MO) is important for improving the performances of QDs-MO devices. And tailoring the energy band of MO is one way to tune the charge transfer rate. In this work, we enhance the charge transfer rate between CdTe QDs and ZnO through tailoring the optical band gap of ZnO nano?lms by Ga-doping. The Ga doping in?uenced the photo luminescence (PL) performance of CdTe QDs/ZnO hybrid structures. The results of time-resolved ?uorescence spectra revealed that the charge transfer rate from CdTe QDs to ZnO nano?lms could be tuned by varying the Ga doping concentrations in ZnO. And, transfer rate were increased by up to ~4.1 times through Ga doping. In addition, the structure showed electron transfer e?ciency improvements to the tune of ~25.3%. We attribute the improvement to e?cient electron transfer via band-band transfer and the defects pathways induced by Ga-doping. The experimental results will be useful for improving the e?ciency of optical devices using QDs/ZnO hybrid structure.
关键词： Doping,Semiconductors,Electron transfer,Time-resolve ?uorescence spectra,QDs/ZnO hybrid structures
更新于2025-09-16 10:30:52
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A Method for Estimating the Functionality of TiO2/Quantum Dot Multilayer Hybrid Structures Based on the Generation of Reactive Oxygen Species
摘要： A new technique for estimating the efficiency of electron transfer from a CdSe/ZnS quantum dot (QD) to TiO2 nanoparticles based on the generation of reactive oxygen species by hybrid structures is presented. It was demonstrated that in the formed multilayer hybrid structures of TiO2/QD, photoinduced electron transfer is realized with an efficiency of 26%.
关键词： hybrid structures,photoinduced electron transfer,semiconductor quantum dots,titanium dioxide nanoparticles,reactive oxygen species
更新于2025-09-12 10:27:22
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Design and Fabrication of Dual-Scale Broadband Antireflective Structures on Metal Surfaces by Using Nanosecond and Femtosecond Lasers
摘要： Antire?ective surfaces, with their great potential applications, have attracted tremendous attention and have been the subject of extensive research in recent years. However, due to the signi?cant optical impedance mismatch between a metal surface and free space, it is still a challenging issue to realize ultralow re?ectance on a metal surface. To address this issue, we propose a two-step strategy for constructing antire?ective structures on a Ti-6Al-4V (TC4) surface using nanosecond and femtosecond pulsed lasers in combination. By controlling the parameters of the nanosecond laser, microgrooves are ?rst scratched on the TC4 surface to reduce the interface re?ection. Then, the femtosecond laser is focused onto the sample surface with orthogonal scanning to induce deep air holes and nanoscale structures, which e?ectively enhances the broadband absorption. The antire?ection mechanism of the dual-scale structures is discussed regarding morphological characterization and hemispherical re?ectance measurements. Finally, the modi?ed sample surface covered with micro-nano hybrid structures is characterized by an average re?ectance of 3.1% over the wavelengths ranging from 250 nm to 2250 nm.
关键词： nanosecond laser,broadband spectrum,femtosecond laser,micro-nano hybrid structures,antire?ective surfaces
更新于2025-09-12 10:27:22