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oe1(光电查) - 科学论文

91 条数据
?? 中文(中国)
  • Surface Modifications for Light Trapping in Silicon Heterojunction Solar Cells: A Brief Review

    摘要: Reducing crystalline silicon (c-Si) wafer thickness is an effective method to reduce the fabrication cost as it constitutes a major portion of the photovoltaic module cost. However, the open-circuit voltage and fill factor depend on the wafer thickness; further, the short-circuit current density (JSC), affects the device performance negatively. Therefore, light trapping is vital for increasing the JSC of Si solar cells. Consequently, it is essential for improving the conversion efficiency of the solar cell and reduce its production cost by decreasing the wafer thickness. It can be assumed that the thickness of the Si wafer will gradually achieve a minimum value of ~ 100?μm in the future. Therefore, reducing the as-cut wafer thickness will result in a more efficient use of Si. This paper reports the surface modification for light trapping based on the Si solar cell application. Additionally, we introduce methods for surface modification, such as front-side texturing and rear-side polishing.

    关键词: Texturing,Polishing,Si solar cell,Surface modification,Light trapping,High efficiency

    更新于2025-09-23 15:21:01

  • Laser printing of micro-electronic communication systems for smart implants applications

    摘要: Endow the implant with intrinsic communication system between sensors and actuators or between implant and patient is a key factor for its long-term success. The capacity of early diagnosis of failures and the ability to remedy them are necessary to minimize expensive complications and reducing revision procedures. Ti6Al4V is the most used titanium alloy for implant’s fabrication. In this sense, this work presents a promising approach to print communication systems by using laser technology, aiming integrate the smart components on titanium implants. Laser has been employed as a versatile tool to modify the surface in different ways, such as texturing, oxidizing and sintering. Silver wires have been printed on Ti6Al4V surface in order to conduct electrical current. To minimize current loss for the substrate, titanium oxide layer has been produced by different methods (laser and anodization). Laser sintering (LS) has been also compared to a conventional method (Hot-pressing- HP) to consolidate the silver powder into the cavities. In comparison to the conventional techniques, laser demonstrated to be a competitive approach to oxidizing the surface and also for consolidating the micro-wires on Ti6Al4V surface. Consequently, the micro-wires printed by laser approach presented satisfactory results in terms of electrical resistance, actuating as the conductor path for electrical current, with values of 0.0131 Ω, which is similar to the resistance of the wire printed in an insulator substrate.

    关键词: Ti6Al4V titanium alloy,Laser oxidation,Implants,Laser surface modification,Nd:YAG laser,Laser sintering

    更新于2025-09-23 15:21:01

  • Surface modification of polyamide 12 angioplasty balloons by photochemical reaction with an aromatic azide

    摘要: Polyamide 12 (PA12) is used in a variety of applications when low moisture absorption, good dimensional stability, and toughness are required. Polyamide 12 is one of the polymers most frequently employed to fabricate angioplasty balloon catheters; however, its high hydrophobicity and chemical inertness require the application of coatings to make its surface more hydrophilic and biocompatible. In this work, an alternative method, based on the photochemical reaction of PA12 with a hydrophilic aromatic azide, was developed. Static and dynamic contact angle measurements evidenced that the surface modification process was able to improve PA12 wettability and that the effects were retained even after 12 months from surface treatment. Polyamide 12 modification resulted in an increase of its surface free energy, as evaluated by the van Oss, Good, and Chaudhury method. X‐ray photoelectron spectroscopy confirmed the presence of the aromatic azide on PA12 surface. Finally, compliance tests showed that the modification process did not reduce the mechanical performance of balloons.

    关键词: contact angle,polyamide 12,angioplasty balloon catheter,surface free energy,surface modification

    更新于2025-09-23 15:19:57

  • Effect of surface modification and laser repetition rate on growth, structural, electronic and optical properties of GaN nanorods on flexible Ti metal foil

    摘要: The effect of flexible Ti metal foil surface modification and laser repetition rate in laser molecular beam epitaxy growth process on the evolution of GaN nanorods and their structural, electronic and optical properties has been investigated. The GaN nanostructures were grown on bare- and pre-nitridated Ti foil substrates at 700 °C for different laser repetition rates (10–30 Hz). It is found that the low repetition rate (10 Hz) promotes sparse growth of three-dimensional inverted-cone like GaN nanostructures on pre-nitridated Ti surface whereas the entire Ti foil substrate is nearly covered with film-like GaN consisting of large-sized grains for 30 Hz growth. In case of the GaN growth at 20 Hz, uniformly-aligned, dense (~8 × 109 cm?2) GaN nanorods are successfully grown on pre-nitridated Ti foil whereas sparse vertical GaN nanorods have been obtained on bare Ti foil under similar growth conditions for both 20 and 30 Hz. X-ray photoemission spectroscopy (XPS) has been utilized to elucidate the electronic structure of GaN nanorods grown under various experimental conditions on Ti foil. It confirms Ga–N bonding in the grown structures, and the calculated chemical composition turns out to be Ga rich for the GaN nanorods grown on pre-nitridated Ti foil. For bare Ti substrates, a preferred reaction between Ti and N is noticed as compared to Ga and N leading to sparse growth of GaN nanorods. Hence, the nitridation of Ti foil is a prerequisite to achieve the growth of dense and aligned GaN nanorod arrays. The X-ray diffraction, high resolution transmission electron microscopy and Raman studies revealed the c-axis growth of wurtzite GaN nanorods on Ti metal foil with good crystallinity and structural quality. The photoluminescence spectroscopy showed that the dense GaN nanorod possesses a near band edge emission at 3.42 eV with a full width at half maximum of 98 meV at room temperature. The density-controlled growth of GaN nanorods on a flexible substrate with high structural and optical quality holds promise for potential applications in futuristic flexible GaN based optoelectronics and sensor devices.

    关键词: Ti metal foil,laser molecular beam epitaxy,optical properties,GaN nanorods,structural properties,surface modification,electronic properties,laser repetition rate

    更新于2025-09-23 15:19:57

  • Enhanced Power Conversion Efficiency of Dye-Sensitized Solar Cells by Band Edge Shift of TiO2 Photoanode

    摘要: By simple soaking titanium dioxide (TiO2) films in an aqueous Na2S solution, we could prepare surface-modified photoanodes for application to dye-sensitized solar cells (DSSCs). An improvement in both the open-circuit voltage (Voc) and the fill factor (FF) was observed in the DSSC with the 5 min-soaked photoanode, compared with those of the control cell without any modification. The UV–visible absorbance spectra, UPS valence band spectra, and dark current measurements revealed that the Na2S modification led to the formation of anions on the TiO2 surface, and thereby shifted the conduction band edge of TiO2 in the negative (upward) direction, inducing an increase of 29 mV in the Voc. It was also found that the increased FF value in the surface-treated device was attributed to an elevation in the shunt resistance.

    关键词: surface modification,conduction band edge shift,dye-sensitized solar cell,sodium sulfide

    更新于2025-09-23 15:19:57

  • Efficient planar heterojunction perovskite solar cells with enhanced FTO/SnO2 interface electronic coupling

    摘要: Ultrathin and compact SnOx amorphous layers derived from SnCl4 were introduced at the interface of electron transport layer (ETL)/perovskite or FTO/ETL to enhance the electron coupling between layers, passivate the trapping defects and optimize the energy level alignment. As results of the increased interface electron collection and reduced interface recombination, the planer perovskite solar cell (PSC) with SnO2 nanocrystal (NC) ETL pre-treated by SnCl4 (Cl-SnO2) shows the power conversion efficiency (PCE) enhancement from 16.3% to 18.6%, and the device hysteresis has also been significantly restrained. In comparison, the planer PSCs with traditional SnCl4 (SnO2-Cl) post-treated SnO2 NC ETL makes the PCE increased from 16.3% to 17.3%. These results indicate that both two kinds of treated ways could improve the performance of the PSCs but compared with the post-treatment process, the devices based on Cl-SnO2 pre-treated ETL present superior performance, which is attributed to the closer contact and enhanced electron coupling between FTO and SnO2 NC ETL with Cl-SnO2 in between.

    关键词: SnCl4 pre-treatment,Perovskite solar cells,Surface modification

    更新于2025-09-23 15:19:57

  • Improved performance of lead-tin mixed perovskite solar cells with PEDOT:PSS treated by hydroquinone

    摘要: Low bandgap lead-tin (Pb-Sn) hybrid perovskite solar cells (PVSCs) have gained a great deal of attentions due to their wide optical absorption range and environmental friendliness. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely used as a hole transport layer for PVSCs. However, the metallic property of PEDOT:PSS causes a barrier at the interface between it and the active layer, thereby hindering the transport of photogenerated carriers. In this paper, in order to eliminate the influence of the interfacial barrier, the PEDOT:PSS surface was treated by hydroquinone (HQ), which lowers the hole transport barrier at the interface, and consequently reduces the interfacial resistance as well. The leakage current in the device with the HQ-treated PEDOT:PSS is significantly reduced, and the surface modification improves the interfacial contact. Compared with the Pb-Sn hybrid PVSCs with the PEDOT:PSS hole transport layer, the power conversion efficiency of PVSCs with the HQ-PEDOT:PSS hole transport layer is improved by 5.7%.

    关键词: Lead-tin hybrid perovskite solar cells,PEDOT:PSS,Surface modification,Hydroquinone

    更新于2025-09-23 15:19:57

  • Electrodeposited MoS2 counter electrode for flexible dye sensitized solar cell module with ionic liquid assisted photoelectrode

    摘要: Dye-sensitized solar cell (DSSC) offers great advantages includes low cost materials, economic fabrication, suitable for low-light conversion, flexibility option, color design possibilities, etc. In the present study, a semi-transparent, molybdenum disulphide (MoS2) flexible counter electrode (CE) is realized through electrodeposition method. Low temperature processed TiO2 solution is used for photoelectrode (PE) preparation. Conductive ionic liquid (BVImI + LiI) is used to modify the surface of photoelectrode for alteration of conduction band level of PE, towards enriched electron injection rate into TiO2. Flexible dye-sensitized solar cell (f-DSSC) fabricated by sandwich the photoelectrode and counter electrodes, and an ionic liquid electrolyte is injected. The surface modified photoelectrode (SM-PE) assisted test cell (0.16 cm2 active area) witnessed an enhanced current density value 12.46 mA/cm2 and power conversion efficiency (PCE) 4.84% is higher than the normal PE based f-DSSC (11.56 mA/cm2 and 4.35%). For comparison, platinum-based f-DSSC with SM-PE is fabricated, is attained 6.08% of PCE. The f-DSSC sub-module with MoS2-CE gave 4.21% of PCE, the results are presented.

    关键词: Surface modification of PE,Imidazolium iodide,Flexible DSSC,Semi-transparent flexible DSSC module,MoS2 counter electrode

    更新于2025-09-23 15:19:57

  • Multifunctional Two-Dimensional Core-Shell MXene@Gold Nanocomposites for Enhanced Photo-Radio Combined Therapy in the Second Biological Window

    摘要: Multi-functional nanoplatforms with special advantages in the diagnosis and treatment of cancer have been widely explored in nanomedicine. Herein, we synthesize two-dimensional core-shell nanocomposites (Ti3C2@Au) via a seed-growth method starting from the titanium carbide (Ti3C2) nanosheets, a classical type of MXene nanostructure. After growing gold on the surface of Ti3C2 nanosheets, the stability and biocompatibility of the nanocomposites are greatly improved by the thiol modification. And importantly, the optical absorption in the near infrared region (NIR) is enhanced. Utilizing the ability of the high optical absorbance and strong X-ray attenuation, the synthesized Ti3C2@Au nanocomposites are used for photoacoustic (PA) and computed tomography (CT) dual-modal imaging. Importantly, the mild photothermal effect of the Ti3C2@Au nanocomposites could improve the tumor oxygenation, which significantly enhances the radiotherapy (RT). None obvious long-term toxicity of the nanocomposites is found at the injected dose. This work highlights the promise of special properties of MXene-based multifunctional nanostructures for cancer theranostics.

    关键词: surface modification,the synergistic effect,combined therapy,titanium carbide nanocomposites,dual-modal imaging

    更新于2025-09-23 15:19:57

  • Mercaptopropyltriethoxysilane (MPTES) Concentration Effect on Selectivity and Electrical Response of Nanostructure

    摘要: The surface modification by on Mercaptopropyltriethoxysilane (MPTES) done to enhance electrical behavior of nano-IDE -based sensor, silicon based active area was coated with MPTES. The electrical properties of modified nano-IDE were tested using impedance analyser by observing the changes in impedance with the frequencies There was increase as the concentration of the MPTES increase from 1 to 5%. The electrical conductivity increases as mobility increase with the surface attenuation by the MPTES. This increase in concertation observed increase of the electrical conductivity with carrier mobility increment, this indicate decrease of the Si–arsenic bond length, which caused the bandgap to be shortened, likewise, The device behaviour to surface modification was capacitive reactive in natured.

    关键词: impedance analyser,nano-IDE,electrical conductivity,Mercaptopropyltriethoxysilane (MPTES),surface modification

    更新于2025-09-23 15:19:57