- 标题
- 摘要
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- 实验方案
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Ultrasonically sprayed-on perovskite solar cells-effects of organic cation on defect formation of CH3NH3PbI3 films
摘要： Methylammonium lead iodide (CH3NH3PbI3) based perovskite having low degrees of the disorder is of great interest for optoelectronic and photovoltaic applications. In this work, a layer of CH3NH3PbI3 was successfully prepared using an ultrasonically sprayed-nebulous method. Changes in structural and optical properties alongside with photo-induced charge separation and transportation behavior were systematically studied. The surface photovoltage spectra reveal a significant reduction of the density of deep defect states as the organic content was increased. It was observed that the measured values of Urbach energies decrease from 33.36 to 28.24 meV as the amount of organic content was increased to an optimum value. The best perovskite solar cells obtained using the sprayed-on approach exhibited a Jsc of 16.54 mA/cm2, a Voc of 0.99 V, and a FF of 62.4, resulting in an overall PCE of 10.09%.
关键词： Ultrasonic-sprayed perovskite,Defect states,Surface photovoltage
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Zhenjiang, China (2019.8.4-2019.8.8)] 2019 IEEE International Conference on Manipulation, Manufacturing and Measurement on the Nanoscale (3M-NANO) - Femtosecond Laser-assisted Fabrication of Fluorescent Boron Nitride Quantum Dots
摘要： As a kind of heavy metal-free quantum dot, boron nitride quantum dots (BNQDs) have attracted great interest due to their unique optical properties. Although there many synthesis methods of BNQDs, most of them require complex or time-consuming procedures, which limits the application of BNQDs. Here, we present a facile synthesizing method of few-layer BNQDs, which is based on liquid-phase ultra-short laser pulse ablation and ultrasonic-assisted exfoliation methods. The fabricated BNQDs are systematically characterized by atomic force microscope, transmission electron microscope, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The products possess an average size of about 2.1 nm with few-layer thickness. Because of the abundant surface functional groups, the BNQDs show bright luminescence emission under UV light irradiation.
关键词： femtosecond laser pulse ablation,ultrasonic-assisted exfoliation,boron nitride quantum dots
更新于2025-09-16 10:30:52
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Improving the effects of laser hardening of steels by applying a longitudinally torsional ultrasonic field
摘要： The paper is devoted to the expediency of using ultrasonic treatment in combination with laser hardening for U8, U10, X12M steels and the study of the effect of ultrasonic longitudinal and torsional acoustic vibrations on the intensification of an increase in the concentration of point defects in the crystal structure. The introduction of a longitudinal and torsional ultrasonic field by transforming longitudinal ultrasonic vibrations made it possible to form a highly concentrated effect, which led to an increase in the effects of laser hardening.
关键词： ultrasonic treatment,crystal structure,steels,laser hardening,longitudinal and torsional acoustic vibrations
更新于2025-09-16 10:30:52
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Flaw Imaging Technique for Plate-Like Structures Using Scanning Laser Source Actuation
摘要： Recently, the longitudinal, shear, and surface waves have been very widely used as ultrasonic wave-based exploration methods to identify internal defects of host structures. In this context, a noncontact nondestructive testing (NDT) method is proposed to detect the damage of plate-like structures and to identify the location of the damage. To achieve this goal, a scanning laser source actuation technique is utilized to generate a guided wave and scans a specific area to find damage location more precisely. The ND:YAG pulsed laser is used to generate Lamb wave and a piezoelectric sensor is installed to measure the structural responses. The measured responses are analyzed using 3-dimensional Fourier transformation (3DFT). The damage-sensitive features are extracted by wavenumber filtering based on the 3DFT. Then, flaw imaging techniques of a plate-like structure are conducted using the damage-sensitive features. Finally, the plates with notches are investigated to verify the effectiveness and the robustness of the proposed NDT approach.
关键词： ultrasonic wave,flaw imaging,scanning laser source,nondestructive testing,wavenumber filtering
更新于2025-09-16 10:30:52
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AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019 - Tomsk, Russia (1a??5 October 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS WITH HIERARCHICAL STRUCTURE FOR NEW TECHNOLOGIES AND RELIABLE STRUCTURES 2019 - Surface modification of selective laser melted Ti-6Al-4V by ultrasonic impact treatment and electron beam irradiation
摘要： Changes of the surface roughness, microstructure, phase composition and microhardness of selective laser melted Ti-6Al-4V samples during electron beam irradiation and ultrasonic impact treatment were investigated by contact profilometry, optical microscopy, X-ray analysis, and hardness measurement. It was shown that electron beam irradiation and ultrasonic impact treatment of the selective laser melted Ti-6Al-4V samples smooth their surface. Significant refinement of the microstructure and TiO nanoparticles formation under ultrasonic impact treatment occur causing the increase in surface microhardness. Electron beam irradiation leads to a more significant increase in both the microhardness and thickness of the melted surface layer due to martensitic transformation.
关键词： Ti-6Al-4V,surface modification,ultrasonic impact treatment,Selective laser melting,electron beam irradiation
更新于2025-09-16 10:30:52
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Synthesis and Characterization of CNT Composites for Lasera??Generated Ultrasonic Waves
摘要： In the last few years, extensive progress in ultrasonic wave generation by using multiwalled carbon nanotubes (MWCNTs) in combination with polydimethylsiloxane (PDMS), functional composites, has been achieved. Due to high optical absorption of MWCNTs as perfect absorbers for laser beams and the high thermal expansion coefficient of PDMS, a compact transducer for ultrasonic wave generation at higher frequency can be realized. This study reports a novel method to synthesize MWCNT–PDMS composites deposited on a glass substrate by spray coating, which is done in a short time of 2 h. The layers (0.9–32.2 μm) show low optical transmission properties of 13.9–0.0% at a wavelength of 1047 nm. Apart from using a 1% Triton-X-100 stock solution and then diluted to a 0.1% relatively nonhazardous solution, no toxic chemicals are used. The Triton-X-100 solution is not hazardous for lab handling and is a commonly used lab detergent for the treatment of biological cells. The achieved sound pressure level is 3.4 MPa with a frequency bandwidth of 9.7 MHz. These results show the potential for a fast and nontoxic production of laser-generated ultrasonic transducers, which can be used well in the field of nondestructive material testing of layered materials or in medicine with an appropriate frequency range.
关键词： laser-generated ultrasonic waves,spray-coating methods,multi-walled CNTs,photophysics,nanocomposites,nanoparticles
更新于2025-09-16 10:30:52
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Tantalum disulfide quantum dots: preparation, structure, and properties
摘要： Tantalum disulfide (TaS2) two-dimensional film material has attracted wide attention due to its unique optical and electrical properties. In this work, we report the preparation of 1 T-TaS2 quantum dots (1 T-TaS2 QDs) by top-down method. Herein, we prepared the TaS2 QDs having a monodisperse grain size of around 3 nm by an effective ultrasonic liquid phase exfoliation method. Optical studies using UV-Vis, PL, and PLE techniques on the as-prepared TaS2 QDs exhibited ultraviolet absorption at 283 nm. Furthermore, we found that dimension reduction of TaS2 has led to a modification of the band gap, namely a transition from indirect to direct band gap, which is explained using first-principle calculations. By using quinine as reference, the fluorescence quantum yield is 45.6%. Therefore, our results suggest TaS2 QDs have unique and extraordinary optical properties. Moreover, the low-cost, facile method of producing high quality TaS2 QDs in this work is ideal for mass production to ensure commercial viability of devices based on this material.
关键词： Transition metal dichalcogenides,First-principle,Quantum dots,Ultrasonic method,Modulating bandgap
更新于2025-09-16 10:30:52
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Residual Stresses in Ultrasonic-Assisted Laser Sintered Grinding Diamond Materials
摘要： Special processing, viz ultrasonic vibration-assisted laser sintering of diamonds was studied. This process would eliminate the drawbacks pertaining to existing super-hard grinding wheels. The composite process fully utilized the odds of laser sintering and ultrasonic vibration to homogenize the structure and reduce residual stresses. Diamond particles were added to a 45 steel matrix using a Ni–Cr alloy via ultrasonic vibration-assisted laser sintering in argon. Metallographic microscopy, and were used to examine the microstructure of a Ni–Cr alloy and abrasive diamond particle bonding interface microstructure, Raman spectrometry was applied to evaluate residual stresses. Acoustic flow and cavitation effects generated by ultrasonic vibration refine crystal grains in the cladding layer and the microstructure is more homogeneous than the microstructure without ultrasonic treatment. A Cr3C2 layer formed on the surface of abrasive diamond particles enhances the bonding ability of a Ni–Cr alloy to diamond, which ensures the diamond isolation and protection, ultrasonic vibration reduces residual stresses inside abrasive diamond particles.
关键词： diamond,laser sintering,ultrasonic vibration,interfacial microstructure,residual stress
更新于2025-09-12 10:27:22
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Semitransparent Sb <sub/>2</sub> S <sub/>3</sub> thin film solar cells by ultrasonic spray pyrolysis for use in solar windows
摘要： The integration of photovoltaic (PV) solar energy in zero-energy buildings requires durable and efficient solar windows composed of lightweight and semitransparent thin film solar cells. Inorganic materials with a high optical absorption coefficient, such as Sb2S3 (>105 cm?1 at 450 nm), offer semitransparency, appreciable efficiency, and long-term durability at low cost. Oxide-free throughout the Sb2S3 layer thickness, as confirmed by combined studies of energy dispersive X-ray spectroscopy and synchrotron soft X-ray emission spectroscopy, semitransparent Sb2S3 thin films can be rapidly grown in air by the area-scalable ultrasonic spray pyrolysis method. Integrated into a ITO/TiO2/Sb2S3/P3HT/Au solar cell, a power conversion efficiency (PCE) of 5.5% at air mass 1.5 global (AM1.5G) is achieved, which is a record among spray-deposited Sb2S3 solar cells. An average visible transparency (AVT) of 26% of the back-contact-less ITO/TiO2/Sb2S3 solar cell stack in the wavelength range of 380–740 nm is attained by tuning the Sb2S3 absorber thickness to 100 nm. In scale-up from mm2 to cm2 areas, the Sb2S3 hybrid solar cells show a decrease in efficiency of only 3.2% for an 88 mm2 Sb2S3 solar cell, which retains 70% relative efficiency after one year of non-encapsulated storage. A cell with a PCE of 3.9% at 1 sun shows a PCE of 7.4% at 0.1 sun, attesting to the applicability of these solar cells for light harvesting under cloud cover.
关键词： solar windows,ultrasonic spray pyrolysis,antimony sulfide,semitransparent solar cells,thin films
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE International Ultrasonics Symposium (IUS) - Glasgow, United Kingdom (2019.10.6-2019.10.9)] 2019 IEEE International Ultrasonics Symposium (IUS) - PMUT-Enabled Underwater Acoustic Source Localization System
摘要： The present work presents the novel application of Piezoelectric Micromachined Ultrasonic Transducer (PMUT) arrays in an Underwater Acoustic Source Localization System. Based on the difference in the time of arrival of ultrasonic bursts originating from an acoustic beacon, the system is capable of determining the direction to the source with no theoretical limitation on the angular range. A cross correlation technique is used to estimate the time of arrival difference between the received signals. Experiments are performed with the prototype submerged in liquid in a tank for arbitrary positions of a beacon, showing large potential for application of the system in a miniaturized, integrated platform for underwater source localization.
关键词： underwater,Direction of Arrival,PMUT,ultrasonic,AVS
更新于2025-09-12 10:27:22