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Elaboration of microporous CeO2 thin layers having nanocrystallites network controlled by Pluronic P123: Impact of key experimental parameters
摘要： Microporous ceria thin ?lms having nanocrystallites network were synthesized by evaporation-induced self-assembly process, using P123 amphiphilic copolymer as structure-directing agent. The impact of key experimental parameters, i.e., the sol ageing, the relative humidity (RH), the thermal treatment, on the thin layer elaboration were investigated. The results show that the organization of the nanoparticles is possible for a sol ageing time lower than 16 days and that the size of the mesophase within the thin layer increases with the relative humidity ?xed during the ?lm deposition. Finally, an increase of the thermal treatment temperature from 300 to 1000 °C leads to the formation of ?uorite-like dioxide material coupled with a loss of nanocrystallites organization and porosity due to the increase of the size of the crystallites. This loss of nanocrystallites organization is more drastic in the direction perpendicular to the surface and less pronounced along the surface. Thus, a compromise between the crystallization and the preservation of the porosity needs to be found.
关键词： relative humidity,P123 amphiphilic copolymer,evaporation-induced self-assembly,nanocrystallites network,thin films,thermal treatment,Microporous ceria,sol ageing
更新于2025-09-16 10:30:52
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Enhanced and switchable silicon-vacancy photoluminescence in air-annealed nanocrystalline diamond films
摘要： Silicon vacancy (SiV) centers in CVD-deposited nanodiamond particles or films always exhibit a photoluminescent (PL)-quenching behavior. Herein, in order to overcome this issue, air annealing of nanocrystalline diamond (NCD) films with uniform doping of Si atoms is employed to improve the PL emission efficiency of SiV centers. Without severe mass loss in diamond, SiV centers exhibit an increased PL emission intensity at 738 nm with an increased annealing temperature and time. In comparison to the untreated film, the maximum PL enhancement reaches about 200 and 1473 folds when the NCD films are annealed at 600 oC for 60 min and 700 oC for 20 min, respectively. Such giant increase in SiV PL emission is mainly attributed to the transition of diamond surface from hydrogen to oxygen termination together with the optimized crystalline quality of the annealed films, as confirmed by the HRTEM, Raman and XPS measurements. A schematic model based on the theory of surface band bending is proposed to elucidate the mechanism of the SiV PL enhancement in oxygen-terminated NCD films: a near-surface light trap layer formed in hydrogen-terminated NCD is converted during the oxidation process, leading to the additional collection of SiV PL emission from the inner layer.
关键词： thermal treatment,luminescence,surface modification,color center,nano-crystalline diamond
更新于2025-09-12 10:27:22
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Thermodynamic control of quantum defects on single-walled carbon nanotubes
摘要： Single-walled carbon nanotubes with designed quantum defects are prepared and characterized. The photoluminescence (PL) of the nanotubes can be modified by thermal treatment from 1215–1224 to 1249–1268 nm. Theoretical calculations suggest that the change in the PL spectra by thermal treatment can be explained by isomerization from kinetic to thermodynamic products.
关键词： quantum defects,Single-walled carbon nanotubes,photoluminescence,thermal treatment,isomerization
更新于2025-09-12 10:27:22
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Four-dimensional optoacoustic monitoring of tissue heating with medium intensity focused ultrasound
摘要： Medium-intensity focused ultrasound (MIFU) concerns therapeutic ultrasound interventions aimed at stimulating physiological mechanisms to reinforce healing responses without reaching temperatures that can cause permanent tissue damage. The therapeutic outcome is strongly affected by the temperature distribution in the treated region and its accurate monitoring represents an unmet clinical need. In this work, we investigate on the capacities of four-dimensional optoacoustic tomography to monitor tissue heating with MIFU. Calibration experiments in a tissue-mimicking phantom have confirmed that the optoacoustically-estimated temperature variations accurately match the simultaneously acquired thermocouple readings. The performance of the suggested approach in real tissues was further shown with bovine muscle samples. Volumetric temperature maps were rendered in real time, allowing for dynamic monitoring of the ultrasound focal region, estimation of the peak temperature and the size of the heat-affected volume.
关键词： photoacoustic imaging,thermal treatment monitoring,therapeutic ultrasound,temperature monitoring,optoacoustic tomography
更新于2025-09-10 09:29:36
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Enhancement of photoluminescence efficiency in GeSe ultrathin slab by thermal treatment and annealing: experiment and first-principles molecular dynamics simulations
摘要： The effect of thermal treatment and annealing under different temperatures from 100 °C to 250 °C on the photoluminescence spectroscopy of the GeSe ultrathin slab is reported. After the thermal treatment and annealing under 200 °C, we found that the photoluminescence intensity of A exciton and B exciton in GeSe ultrathin slab is increased to twice as much as that in untreated case, while is increased by ~84% in the photoluminescence intensity of C exciton. Combined by our experimental work and theoretical simulations, our study confirms the significant role of thermal treatments and annealing in reducing surface roughness and removing the Se vacancy to form more compact and smoother regions in GeSe ultrathin slab. Our findings imply that the improved quality of GeSe surface after thermal treatments is an important factor for the photoluminescence enhancement.
关键词： annealing,ultrathin slab,first-principles molecular dynamics,GeSe,photoluminescence,thermal treatment
更新于2025-09-10 09:29:36
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Effects of ultraviolet photon irradiation and subsequent thermal treatments on solution-processed amorphous indium gallium zinc oxide thin films
摘要： Effects of exposure to ultraviolet (UV) photons and thermal treatments on solution-processed amorphous indium gallium zinc oxide (a-IGZO) films were investigated by X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. As a result, oxygen vacancies obviously become more abundant in the films sintered at 250 or 300 ?C by the exposure to 7.21 eV photons and less abundant by the subsequent thermal treatment at 250 ?C in air. The drain current also clearly becomes smaller in a thin film transistor fabricated using the IGZO film in a manner opposite to the abundance of oxygen vacancies. That is, the drain current becomes smaller by the UV irradiation and returns to the original high value by the subsequent thermal treatment. This indicates that oxygen vacancies act as trapping centers or scattering centers of electrons. In addition, the reversible change of the drain current with the cycle of UV irradiation and the thermal treatment opens the possibility of the use of the IGZO films as a UV sensor.
关键词： oxygen vacancies,amorphous indium gallium zinc oxide,thin film transistor,UV irradiation,thermal treatment
更新于2025-09-10 09:29:36
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End-of-life of silicon PV panels: A sustainable materials recovery process
摘要： In this paper, the management of end-of-life PV modules based on an advanced eco-sustainable process has been presented and discussed. The thermal removal of the polymeric compounds contained in c-Si PV modules has been investigated to separate and recover Si, Ag, Cu, Al and glass. A two-step thermal process has been employed. In the first step, the rear polymeric layer has been removed without emissions of dangerous fluorinated substances. In the second step, the remaining polymers have been completely removed with low volatile organic compounds (VOCs) emissions. The polymers degradation has been studied at combustion equivalent ratios U varying from 0.5 to 2 and at 500 °C. The materials recovery has been evaluated from an environmental point of view and optimized by considering the energy cost, through the identification of the best operating conditions, in terms of temperature, time, atmosphere and gas flow. One hour of heat treatment and a slightly oxidizing atmosphere have been enabled to separate and recover the different materials of the module. The elemental compositions of the PV sample and the residue condensed organic products have been determined. The gaseous degradation products have been characterized by gas chromatographic analysis (GC).
关键词： Recycling,Photovoltaic module,Thermal treatment,Polymer removal,Energy consumption
更新于2025-09-09 09:28:46
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Deoxynivalenol Decontamination in Raw and Germinating Barley Treated by Plasma-Activated Water and Intense Pulsed Light
摘要： The contamination of barley kernel by Fusarium fungi constitutes a serious problem for malting-related industries. Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium fungi. DON can affect dopaminergic receptors in the human brain; it may cause symptoms such as vomiting, diarrhea, headache, and fever. The aims of this study were to evaluate the DON destruction effect of the intense pulsed light (IPL) and plasma-activated water (PAW) treatments in raw and germinating barley and assess the feasibility for disinfection in the malt industry. Both non-thermal methods degraded DON concentration in germinating barley. IPL treatment significantly reduced (p < 0.05) the DON level of germinating barley samples by 35.5% after 180 pulses in 60 s, and the PAW treatment effectively degraded the DON level by 34.6% in germinating barley in the first 5 min. However, higher barley quality remained for PAW treatment (germination rate: 81–100%) than for the IPL treatment (germination rate: 41–60%). For the raw barley samples, although significant reduction (30.9%) was achieved after 180 pulses of IPL treatment, noticeable quality (germination rate: 20–40%) alteration was observed. Significantly less DON degradation was achieved by the PAW treatment on raw barley than the germinating barley for all times. Overall, these findings suggested that PAW and IPL might potentially be used to reduce DON levels in some malt-related industry applications, and PAW was recommended as a better method than IPL to maintain the barley quality.
关键词： Deoxynivalenol degradation,Non-thermal treatment,Barley kernel,Plasma-activated water,Intense pulsed light
更新于2025-09-09 09:28:46
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Toward reproducible metal-insulator transition characteristics in V <sub/>2</sub> O <sub/>3</sub> thin films sputter-deposited on glass
摘要： Vanadium sesquioxide (V2O3) exhibits remarkable property changes through its metal-insulator transition near 150 K and is a very promising candidate for device applications. Thin V2O3 films were deposited on SiO2 glass by reactive DC magnetron sputtering. While resistivity changes over four orders of magnitude were demonstrated, films deposited under nominally identical conditions exhibited significant differences in electrical characteristics, which would hinder reproducibility under deposition techniques appropriate for industrial scale production with standard control features. These differences were attributed to small deviations from exact stoichiometry. A post-deposition thermal treatment consistent with equilibrium temperature and oxygen pressure conditions for V2O3 applied to the samples succeeded in nearly equalizing their characteristics within a relatively short time and without negatively impacting the glass substrate or film continuity. Analysis of film structure, morphology, and resistivity measured from room temperature through the metal-insulator transitions, both before and after the thermal process, revealed information about the interplay between non-stoichiometry, residual stress, and electrical characteristics of the films. The approach employed can lead to reproducible results for V2O3 films and is applicable to similar materials which exhibit metal-insulator transitions.
关键词： stoichiometry,sputtering,thin films,V2O3,thermal treatment,metal-insulator transition
更新于2025-09-09 09:28:46
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The role of adsorbed water on TiO <sub/>2</sub> particles in the electrorheological effect
摘要： TiO2 particles prepared by the hydrolysis of titanium butoxide adsorb water molecules with different adsorption energies. The electrorheological (ER) ?uid composed of TiO2 particles behaves as the polar-molecule giant electrorheological (GER) ?uid at 25?C even after thermal treatment at 75?C. After thermal treatment at 125?C and 175?C, the water molecules with low adsorption energy are removed and the ER ?uid behaves as traditional ER ?uid at 25?C. However, at 175?C, the ER ?uid treated at 175?C behaves as a polar-molecule GER ?uid when the external electric ?eld is larger than 2 kV/mm. These results show that the water molecules with low adsorption energy act as polar molecules responsible for the GER effect and, with the help of thermal energy, water molecules with high adsorption energy can work as those with low adsorption energy, resulting in the GER effect.
关键词： TiO2 particles,electrorheological effect,polar-molecule GER ?uid,adsorbed water,thermal treatment
更新于2025-09-09 09:28:46