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Universal defects elimination for high performance thermally evaporated CsPbBr3 perovskite solar cells
摘要： Inorganic CsPbBr3 perovskite has emerged as a promising material for fabricating highly stable perovskite solar cell devices. However, during the formation of thermally evaporated CsPbBr3 film, an all-solid reaction between CsBr and PbBr2 leads to non-uniform interfaces and high defect density in the perovskite film. In this work, we utilize a two-step sintering (TSS) method which successfully modifies the morphologies of thermally evaporated CsPbBr3 films and the power conversion efficiency of a champion CsPbBr3 perovskite solar cell achieves 9.35%. Steady-state photoluminescence, time-resolved photoluminescence and space-charge-limited-current results prove that the TSS process can effectively reduce defect densities also. Besides these improvements, the TSS device maintains 94% of initial efficiency after being heated at 100°C without encapsulation for over 40 days under ambient lab condition. In comparison, the untreated device reduces about 15%. Transmission electron microscope results further prove the reduction of line defects in CsPbBr3 crystals after TSS treatment.
关键词： Two-step sintering,Defects elimination,Thermal evaporation method,All-inorganic CsPbBr3 perovskite solar cells
更新于2025-09-11 14:15:04
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Electrical Properties of Indium-Oxide Thin Films Produced by Plasma-Enhanced Reactive Thermal Evaporation
摘要： The structure and electrical properties of transparent indium-oxide thin films produced by plasma-enhanced reactive thermal evaporation at different substrate temperatures are studied. It is found that the films have a grained structure. An increase in the substrate temperature yields a considerable increase in the conductivity of the films and a decrease in the photoconductivity-relaxation time. An interpretation of the effect of the substrate temperature on the observed changes in the electrical and photoelectric properties of the indium-oxide films under study is proposed.
关键词： indium-oxide thin films,electrical properties,substrate temperature,photoconductivity,plasma-enhanced reactive thermal evaporation
更新于2025-09-11 14:15:04
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Formation of CH <sub/>3</sub> NH <sub/>2</sub> -incorporated intermediate state in CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> hybrid perovskite thin film formed by sequential vacuum evaporation
摘要： CH3NH3PbI3 thin films were formed with various deposition rates of PbI2 first layer using a sequential vacuum evaporation method (SVE) to understand the formation behavior. Under low PbI2 deposition rates with 1 and 3 ? s?1, the thin films did not form the hybrid perovskite structure. Over the 6 ? s?1 deposition rate, the perovskite structure is observed with the remaining PbI2 and an intermediate phase together. In the 10 ? s?1, the intermediate phase is increased, and the CH3NH2 molecular defect is observed. The hybrid perovskite thin film formed by SVE is confirmed with tiny grains and CH3NH2-incorporated intermediate state.
关键词： CH3NH3PbI3,intermediate phase,CH3NH2 molecular defect,sequential vacuum evaporation,hybrid perovskite
更新于2025-09-10 09:29:36
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Investigations on synthesis, growth and physicochemical properties of semi-organic nonlinear optical crystal: l-arginine sodium nitrate
摘要： Single crystals of l-arginine sodium nitrate semiorganic nonlinear optical crystal were grown by slow evaporation process at room temperature. The single crystal X-ray diffraction study confirms that the unit cell parameters of the grown l-arginine sodium nitrate crystal. Fourier transform infrared spectrum analysis was used to identify the functional groups of the grown crystal. The thermal stability of the l-arginine sodium nitrate was determined using thermogravimetric analysis and differential thermal analysis. The linear optical property of LARSN crystal has been studied using Ultraviolet–visible spectroscopy studies in the wavelength range 200–800 nm. The relative second harmonic efficiency of the l-arginine sodium nitrate compound is found to be 0.49 times that of Potassium Di-hydrogen phosphate. The mechanical property of the grown crystals was determined by Vicker’s micro hardness test and it proved the hard nature of the grown crystal. Dielectric study reveals that both dielectric constant and dielectric loss decreases with increase in frequency.
关键词： thermal analysis,l-arginine sodium nitrate,slow evaporation process,FTIR,nonlinear optical crystal,microhardness,dielectric properties,X-ray diffraction,SHG efficiency,UV–Vis spectroscopy
更新于2025-09-10 09:29:36
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Physical properties of fluorides barium and calcium nanopowders produced by the pulsed electron beam evaporation method
摘要： The mesoporous nanocrystal powders BaF2 and CaF2 with a specific surface up to 34.8 and 88.7 sq.m/g, respectively, are produced by the pulsed electron beam evaporation method in vacuum. The influence of thermal annealing of nanoparticles on air in the range of temperature from 200 to 900°C on the size, morphology of particles and change of their magnetic and luminescent properties investigated have been investigared. The essential stoichiometric impurity (overage of metals) and significant growth in a specific surface of nanopowders (NP) BaF2 and CaF2 after annealing at the temperature of 200°C have been detected. It is established that the synthesized NP BaF2 is a paramagnetic while initial material in the bulk state is diamagnetic. After annealing at 900°C appears the small ferromagnetic contribution at NP BaF2. Produced NP CaF2 showed ferromagnetic behavior. In literature there is no information about the ferromagnetism of CaF2. Appearance of the ferromagnetic response can be explained with formation of structural and radiation defects (F-centers, etc.). The analysis of PCL and magnetization curves of samples BaF2 and CaF2 allows drawing conclusions about their connection.
关键词： CaF2,pulsed electron beam evaporation,magnetic properties,luminescent properties,nanopowders,BaF2
更新于2025-09-10 09:29:36
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Structural and thermoelectric properties of Se doped In <sub/>2</sub> Te <sub/>3</sub> thin films
摘要： The Se-Te based chalcogenides exhibit novel property of Phase Change Memory (PCM) which has potential applications in electrical non-volatile memories. These materials are also suitable in thermal to electrical energy conversions and, hence, of potential interest in energy sustainability as thermoelectric devices. In this study, the Se doped In2Te3 thin films were prepared by thermal evaporation and were annealed at 250 ?C and 300 ?C in Argon gas. The X-ray diffraction spectra show that thermal annealing leads to the phase transitions in Se doped In2Te3 into binary phases of In2Se3 and In2Te3. The surface morphology of the films exhibits the grains of spherical nature. Annealing also decreases the energy band gap due to the presence of two phases. From the four probe and photoconductivity measurements, a large contrast in electrical resistance between the amorphous and crystalline states is found with a variation of a few orders of magnitude. The electrical transport properties such as the electrical resistivity, Seebeck coefficient and the power factor were measured in the temperature range from 300 K to 430 K. All the deposited and annealed thin films exhibit n-type conductivity with the Seebeck coefficient ranging from -338 μVK-1 to -510 μVK-1. An increase in thermoelectric power of 25% is observed in the 300 ?C annealed films in comparison to the as-deposited films. Moreover, the lower Se doped In2(Te0.96Se0.04)3 compound exhibits a better thermoelectric performance compared to the In2(Te0.90Se0.1)3 composition. This study shows the multifunctional nature of Se doped In2Te3 both for PCM and thermoelectric applications.
关键词： power factor,Seebeck coefficient,Phase Change Memory,X-ray diffraction,thermal evaporation,Se-Te based chalcogenides,electrical resistance,thermoelectric devices
更新于2025-09-10 09:29:36
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[Energy, Environment, and Sustainability] Advances in Solar Energy Research || Experimental Investigation into the Applicability of Nanoparticles in Purification of Sewage Water Through Usage of Solar Energy
摘要： In recent years, solar energy driven water desalination/puri?cation systems have been extensively researched with the objective of improving the distillate yield. In these conventional solar driven systems, solar energy heats the water indirectly i.e. in these systems the solar energy is transferred to the water through conduction, resulting in evaporation and hence puri?cation of the water. The present work explores the idea of adding nanoparticles into the wastewater so that solar energy is transferred to water volumetrically, which considerably improves the evaporation rate. Amorphous carbon nanoparticles have been used owing to their high solar weighted absorptivity values. Careful experiments have been carried out to quantify the effect of nanoparticles on the evaporation rate. It was found that optimum level of nanoparticles addition could actually enhance the evaporation rates of the sewage water by *15%. Furthermore, total dissolved solids (TDS) and pH measurements showed considerable improvements, the values being in the range to qualify for drinkable water.
关键词： Evaporation,Nanoparticles,Condensation,Solar energy,Sewage water
更新于2025-09-10 09:29:36
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Change in the morphology of SnO<sub>2</sub> crystals synthesized by thermal evaporation of SnO<sub>2</sub> powder mixed with graphite in ambient air
摘要： The morphology of tin oxide (SnO2) crystals, which were formed by thermal evaporation of SnO2/graphite powder mixture, was changed with the ratio of graphite to SnO2 powder in the source material. The synthesis process was performed in air at atmospheric pressure and no catalysts and substrates were used, which makes the process very simple and low cost. At the low ratios of graphite to SnO2 powder in the source material, the SnO2 crystals had a spherical shape with nanometer dimensions. With increasing the ratio of graphite to SnO2 powder, the morphology of SnO2 crystals changed from particle to belt. The belt-shaped SnO2 crystals had the widths in the range of 1.2–3.1 μm and the lengths of several tens of micrometers. X-ray diffraction analysis showed that all the SnO2 crystals had a rutile tetragonal crystal structure. Visible emission band with the wavelength in the range of 400–600 nm was observed in the cathodoluminescence spectra of the SnO2 crystals.
关键词： Graphite,Mixing ratio,Air,Tin oxide,Thermal evaporation,Morphology variation
更新于2025-09-10 09:29:36
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Combined Infrared Thermography, X-ray Radiography, and Computed Tomography for Ink Drying Studies
摘要： This work describes the comparison of drying behavior of ink deposited on two substrates used commonly in polymer electrolyte fuel cells (PEFCs): microporous layer (MPL) and Nafion. For the same drying conditions and ink composition, ink deposited onto the MPL dried faster and also formed cracks faster. During drying, ink deposited on the MPL had more cracks and smaller intercrack spacing compared to ink deposited on Nafion. Smaller intercrack spacing for ink on the MPL substrate is explained by the higher critical stress predicted by the model. A novel combination of infrared (IR) thermography, X-ray radiography, and computed tomography (CT) is used to characterize ink drying behavior. X-ray radiography with fast temporal resolution showed the existence of skin on the top of drying film that formed due to slow convective ink transport within the film and fast evaporative drying. From X-ray CT, detailed three-dimensional data was obtained on crack morphology within the drying film and was correlated to temperature profiles obtained with IR-thermography. The formation of a Y-crack in the film deposited on the MPL was correlated to the defect within the MPL substrate. The combination of three techniques is a unique probe to capture the temporal, thermal, and morphological evolution of drying ink.
关键词： IR thermography,fuel cells,evaporation,X-ray computed tomography,X-ray radiography,ink drying
更新于2025-09-10 09:29:36
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Substrate temperature dependent variation in the properties of cadmium telluride thin films deposited on glass
摘要： The present study relates to the variation in properties of cadmium telluride (CdTe) thin films deposited via electron beam and thermal vacuum evaporation methods at two different substrate temperatures. The influence of substrate temperature on structural, morphological, optical and electrical properties of CdTe thin films is investigated. For structural characterization, grazing incidence X-ray diffraction technique is used which revealed that thin films deposited at 200 °C temperature are more crystalline in nature as compare to the room temperature. The parameters such as average crystallite size (D), lattice strain (ε), number of crystallites per unit area (N) and texture coefficient TC (hkl) were calculated for both types of synthesized CdTe thin films. Surface morphology of thin films was recorded using scanning electron microscopy and found to be homogeneous in nature. The optical studies carried out using UV–Visible Spectrophotometer and Photoluminescence shown a decrease in band gap values for both electron beam and thermally deposited thin films samples at 200 °C substrate temperature. Electrical measurements recorded using two probes method showed the maximum value of current for CdTe thin films deposited by electron beam evaporation method at 200 °C substrate temperature.
关键词： Thermal vacuum evaporation,Optical properties,Thin films,Electron beam evaporation,Electrical properties,Structural properties,Substrate temperature,Cadmium telluride
更新于2025-09-09 09:28:46