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Impact of Laser Structuring on Medical-Grade Titanium: Surface Characterization and In Vitro Evaluation of Osteoblast Attachment
摘要： Improved implant osteointegration offers meaningful potential for orthopedic, spinal, and dental implants. In this study, a laser treatment was used for the structuring of a titanium alloy (Ti6Al4V) surface combined with a titanium dioxide coating, whereby a porous surface was created. The objective was to characterize the pore structure shape, treatment-related metallographic changes, cytocompatibility, and attachment of osteoblast-like cells (MG-63). The treatment generated specific bottleneck pore shapes, offering the potential for the interlocking of osteoblasts within undercuts in the implant surface. The pore dimensions were a bottleneck diameter of 27 μm (SD: 4 μm), an inner pore width of 78 μm (SD: 6 μm), and a pore depth of 129 μm (SD: 8 μm). The introduced energy of the laser changed the metallic structure of the alloy within the heat-affected region (approximately 66 μm) without any indication of a micro cracking formation. The phase of the alloy (microcrystalline alpha + beta) was changed to a martensite alpha phase in the surface region and an alpha + beta phase in the transition region between the pores. The MG-63 cells adhered to the structured titanium surface within 30 min and grew with numerous filopodia over and into the pores over the following days. Cell viability was improved on the structured surface compared to pure titanium, indicating good cytocompatibility. In particular, the demonstrated affinity of MG-63 cells to grow into the pores offers the potential to provide significantly improved implant fixation in further in vivo studies.
关键词： orthopedics,titanium,surface,osteointegration,coating,dental,laser
更新于2025-09-23 15:21:01
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Trap State and Charge Recombination in Nanocrystalline Passivized Conductive and Photoelectrode Interface of Dye-Sensitized Solar Cell
摘要： The dynamic competition between electron generation and recombination was found to be a bottleneck restricting the development of high-performance dye-sensitized solar cells (DSSCs). Introducing a passivation layer on the surface of the TiO2 photoelectrode material plays a crucial role in separating the charge by preventing the recombination of photogenerated electrons with the oxidized species. This study aims to understand in detail the kinetics of the electron recombination process of a DSSC fabricated with a conductive substrate and photoelectrode film, both passivized with a layer of nanocrystalline TiO2. Interestingly, the coating, which acted as a passivation layer, suppressed the back-electron transfer and improved the overall performance of the integrated DSSC. The passivation layer reduced the exposed site of the fluorine-doped tin oxide (FTO)–electrolyte interface, thereby reducing the dark current phenomenon. In addition, the presence of the passivation layer reduced the rate of electron recombination related to the surface state recombination, as well as the trapping/de-trapping phenomenon. The photovoltaic properties of the nanocrystalline-coated DSSC, such as short-circuit current, open-circuit voltage, and fill factor, showed significant improvement compared to the un-coated photoelectrode film. The overall performance efficiency improved by about 22% compared to the un-coated photoelectrode-based DSSC.
关键词： Electron recombination,electrochemical analysis,nanocrystalline coating,Dye-sensitized solar cell,passivation layer
更新于2025-09-23 15:21:01
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Late-stage Customization in Volume Production of Organic Photovoltaics
摘要： Organic photovoltaics (OPV) in free-form shapes have become a unique feature compared to other thin-film photovoltaic technologies. The ability to conform coated layers to any form of shape or structure is a game changer for OPV and creates a paradigm shift in conventional energy businesses. As urban growth prevails, the energy requirement must be compensated by modern means and OPVs provide unique properties where its form or shape can be fully customized. This creates a synergy as they are then easily integrated onto structures or even products. By doing so not only the space requirements are diminished but the energy is delivered directly to the point of use rather than having them transported from central harvesting. The present communication discusses the advances in realizing such free-from patterns by structuring the functional layers to shape after they have been deposited which is referred to as late-stage customization. Using this approach, a pre-coated generic OPV material can be converted into any design upon customer request. The advantages include easier planning, shorter lead times in production as well as paving the way towards lean manufacturing.
关键词： renewable energies,mass production,organic photovoltaics (OPV),laser scribing,slot-die coating,module customization,roll-to-roll fabrication,dielectric material
更新于2025-09-23 15:21:01
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An Effective Method for Recovering Nonradiative Recombination Loss in Scalable Organic Solar Cells
摘要： Regarded as a critical step in commercial applications, scalable printing technology has become a research frontier in the field of organic solar cells. However, inevitable efficiency loss always occurs in the lab-to-manufacturing translation due to the different fabrication processes. In fact, the decline of photovoltaic performance is mainly related to voltage loss, which is mainly affected by the diversity of phase separation morphology and the chemical structures of photoactive materials. Fullerene derivative indene-C60 bisadduct (ICBA) is introduced into a PBDB-T-2F:IT-4F system to control the active layer morphology during blade-coating process. Accordingly, as a symmetrical fullerene derivative, ICBA can regulate the crystallization tendency and molecular packing orientation and suppress charge carrier recombination. This ternary strategy overcomes the morphology issues caused by weaker shear impulse in blade-coating process. Benefiting from the reduced nonradiative recombination loss, 1.05 cm2 devices are fabricated by blade coating with a power conversion efficiency of 13.70%. This approach provides an effective support for recovering the voltage loss during scalable printing approaches.
关键词： nonradiative recombination loss,organic solar cells,large-area solar cells,blade coating
更新于2025-09-23 15:21:01
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A novel CdTe ink-assisted direct synthesis of CdTe thin films for the solution-processed CdTe solar cells
摘要： The CdTe ink in thiol-amine cosolvents from CdTe powder has been successfully prepared via Triton X-100 surfactant at 50 °C. The CdTe thin films have been synthesized and characterized from the prepared CdTe ink using spin coating method. The SEM micrographs reveal that synthesized films are uniform, smooth and homogeneous with less cracks, voids and pinholes compared to the films deposited from the inks without surfactant. The XRD spectra confirm the mixed hexagonal and cubic structure of the deposited films. The Raman peaks at 142 and 122 cm-1 indicate the CdTe and the pure Te phase, respectively. The FTIR peaks at 1638 and 1384 cm-1 due to C=O and COO- groups originated for the stretching vibration of the ligands of the thiol-capped CdTe, and the absence of vibrational peaks of S–H in the range of 2550–2650 cm-1 confirms the thiol-capped CdTe, respectively. The EDX results reveal the existence of Cd and Te elements in CdTe films. The deposited films exhibit the highest absorbance (*85%) with a band gap of 1.5 eV. Hall studies and electrical analysis indicate the high quality of the CdTe films. Therefore, it can be concluded that the developed surfactant-mediated CdTe ink is highly promising for solution-processed CdTe-based photovoltaics.
关键词： spin coating,Triton X-100 surfactant,thiol-amine cosolvents,CdTe ink,CdTe thin films,photovoltaics
更新于2025-09-23 15:21:01
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Study on ?′-ferrite evolution and properties of laser fusion zone during post-weld heat treatment on Al-Si coated press-hardened steel
摘要： Laser welding of Al-Si coated press-hardened steel (PHS) was still a challenging due to the formation of ?-ferrite in the fusion zone. However, it was ambiguous on the ?-ferrite evolution during post-weld heat treatment (PWHT). In this study, Al-Si coated PHS was welded by laser ?ber and then heat-treated at various temperatures (650 ?C, 950 ?C and 1050 ?C), and the microstructure evolution was investigated by in situ-observation. Mechanical properties and formability of welded joints was analyzed. The results showed that ?-ferrite did not go through phase transformation during PWHT regardless of any temperature, but with a grain boundary ?atted and movement. The presence of coarse ?-ferrite after PWHT was the responsible for the decreasing of tensile strength and formability of welded joints. The initiation crack was easy to generate in the phase interface between ?-ferrite and martensite to form a local brittle fracture zone ?nally. This study results provides a new theoretical criterion for the properties improvement on the laser welding of PHS without removing Al-Si coating.
关键词： Laser welding,Post-weld heat treatment,Al-Si coating,Press hardened steel ?-ferrite
更新于2025-09-23 15:21:01
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Hybrid nanoparticle layers toward enhanced luminescence of phosphor plates for white LEDs
摘要： MgF2 porous nanoparticle-silica hybrid coating layers were utilized to enhance luminescence efficiency of phosphor plates for white light emitting diodes (wLEDs). Silica and chemically synthesized porous MgF2 nanoparticles were sequentially deposited by spin coating on the phosphor plate with phosphor-in-glass (PiG) configuration. Microscopic investigation the hybrid film suggested intermixing of silica and porous MgF2 nanoparticles. Numerical estimation based on transfer matrix method expected a significant reduction in reflectance and enhancement of transmission spectra by the hybrid coating. In accordance, the photoluminescence intensity of phosphor plates showed a drastic improvement and quantum yield were enhanced from 30% (for bare PiG plate) to 45% (for hybrid layer coated PiG plate). When assembled with blue LEDs, hybrid nanoparticle coating on the PiG phosphor plates improved luminescence efficacy from 40 lm/W to 49 lm/W without deterioration of chromaticity during operation. In addition, mechanical durability of the hybrid thin film was confirmed by abrasion test. Conformal coating of matching layer consisting of porous MgF2 nanoparticles and silica can provide an efficient route to highly luminescent white LEDs with mechanical stability.
关键词： refractive index,phosphor-in-glass,nanoparticles,Luminescence,Hybrid coating
更新于2025-09-23 15:21:01
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[Institution of Engineering and Technology 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Lecce, Italy (23-25 May 2018)] 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Second Harmonic Generation Circul Dichroism in Au Coated Gaas-based Nanowires
摘要： Nanostructures with broken symmetry can interact with circularly polarized light to mimic chiroptical (chiral-optical) effects, usually observable in chiral media. This phenomenon is known as extrinsic chirality. Second harmonic generation (SHG) is extremely sensitive to symmetry breaking, down to a single atomic monolayer and it has been extensively used as a probe of extrinsic chirality. Here we present SHG measurements of GaAs nanowires partially covered with Au, fabricated by a self-catalysed technique. The Au coated GaAs nanowires give rise to a dramatic circular dichroism in the generated second harmonic signal, compared to nanowires without coating.
关键词： plasmonic coating,extrinsic chirality,second harmonic generation,GaAs nanowires
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Efficiency Improvement of Planar Silicon Solar Cells Utilizing Localized Surface Plasmon Resonance of Silver Nanoparticles
摘要： In this work we develop a time- and cost-effective method of fabricating an antireflection structure on Si solar cells utilizing the localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs). Covered with an Al2O3 layer to prevent degradation, the NP decorated Si solar cell exhibits a broadband light absorption enhancement, having a low weighted average spectral reflectance (Rave) value of 9.5%, and exhibits the highest absolute gain of 19.2% in external quantum efficiency (EQE) at 700 nm and an overall 20% relative increase in power efficiency (η) compared to the reference Si solar cell without NPs.
关键词： metal nanoparticles,localized surface plasmon resonance,antireflection coating,silicon
更新于2025-09-23 15:21:01
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Roll-to-Roll Slot-Die Coated P-I-N Perovskite Solar Cells Using Acetonitrile Based Single Step Perovskite Solvent System
摘要： Roll-to-roll coating of all active layers is demonstrated for a P-I-N perovskite solar cell stack, using a single step perovskite ink with an acetonitrile solvent system and flexible plastic substrate. A slot-die coating roll-to-roll process (with a common coating speed for all layers) is developed by using appropriate length meniscus guides as part of the coating head for each ink rheology. High performance devices are demonstrated with four roll-to-roll slot-die coated layers and evaporated top electrode. The drying conditions of the perovskite layer are optimized and found to be critical to achieving good performance. Multi solvent blend systems for the electron collection layer are developed that are more industrially compatible than the commonly used chlorobenzene solvent system and make use of a gradient of solvent volatilities to give both good macro film formation and rapid drying. A stabilised power conversion efficiency of 12.2% is demonstrated, that is the highest reported to date for devices with all layers other than the top electrode deposited roll-to-roll. This work demonstrates the feasibility of a roll-to-roll fabrication process for perovskite solar cells that could be transferred to a fully inline roll-to-roll process with all coating and drying stages made sequentially on one line running at a common coating speed and further demonstrates the potential to produce high efficiency photovoltaics using roll-to-roll fabrication methods.
关键词： Stabilised power conversion efficiency,Perovskite solar cells,Slot-die coating,Roll-to-roll,Acetonitrile solvent system
更新于2025-09-23 15:21:01