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Deposition of Cu2ZnSnS4 films by doctor blade printing using a one-step microwave heated ink as an absorber layer for solar cells
摘要： Kesterite (Cu2ZnSnS4, CZTS) semiconductors are known as the most suitable compounds for the synthesis of absorber layers. These compounds are used in solar cells due to their high solar energy absorption coe?cient and ideal band gap. In the present work, the microwave-assisted process and doctor blade printing were used to prepare Cu2ZnSnS4 ?lms. To this aim, ink solution was used, which consisted of copper, zinc acetate, tin chloride and thiourea as copper, zinc, tin and sulfur precursors, respectively. Ethylene glycol was used as a non-toxic solvent. The CZTS ink was prepared using microwave heating for 10 min. The CZTS layers were printed on soda lime silica glass substrates and heat treated at 150, 200, 250, 300, and 350°C. The microstructure, phase analysis, morphology, optical properties, and absorption ratio of the samples were evaluated using X-ray di?raction analysis, Raman spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, transmittance spectroscopy, ?eld emission scanning electron microscopy (FESEM), energy dispersive X-ray, and UV–Vis spectrophotometry. The formation of the Kesterite structure was con?rmed using X-ray di?raction and Raman spectroscopy. The FESEM micrographs and DLS (dynamic light scattering) revealed that the ?lms contained equated grains with the diameter range of 350–650 nm. According to the X-ray analysis and Raman spectrum, the highest crystallization and purity of the Kesterite phase as well as the best microstructure property and morphology (smooth spherical particles with good adhesion) of the CZTS ?lms were found in the synthesized specimen at 300°C. The band gap of the samples was measured to be about 1.5 eV using UV–Vis spectrophotometry.
关键词： Microwave heating process,UV–Vis spectrophotometry,Solar cell,CZTS ?lm
更新于2025-09-16 10:30:52
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Impurities in large scale produced Nd-doped phosphate laser glasses. II. Pt ion and Pt inclusion
摘要： Platinum is a special kind of impurity in Nd-doped phosphate laser glasses. Firstly, its presence in the glass depends on the production processes, rather than the purity of the raw materials used. Secondly, there coexist Pt ion and Pt inclusion in the glass, which one is the oxidized and the other is the reduced. The detection for these two kinds of Pt impurities in the large-scale produced Nd-doped phosphate laser glasses can re?ect the control level and stability of the processes. To determine more accurately the content of Pt ion in the glass, a hemi-cyanine dye, instead of SnCl2 previously used, is utilized to color Pt ion solution by dissolving the glass. On the basis of such a new hemi-cyanine spectrophotometric analysis, the factor of proportionality between Pt ion content and its absorption coe?cient at 400 nm is determined and discussed. To avoid the interference from other cations in the multi-cation solution by dissolving the glass, when doing ICP-MS analysis for Pt, a magnetic poly-ionic liquid is synthesized successfully by bonding an ionic liquid to nano-Fe3O4 particles covered by C. Such a new magnetic poly-ionic liquid can adsorb Pt ions with a better selection. The element distribution of Pt, O and P for di?erently sized Pt inclusions in the glass is analyzed by EPMA.
关键词： Pt ion,Pt inclusion,Selective adsorption for Pt ion,EPMA,Spectrophotometry,Nd-Doped phosphate laser glass
更新于2025-09-12 10:27:22
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Ammonia in Jupiter’s Atmosphere: Spatial and Temporal Variations of the NH3 Absorption Bands at 645 and 787 Nm
摘要： Based on the material of long-term spectrophotometric observations of Jupiter, we studied the weak absorption bands of ammonia at 645 and 878 nm, whose behavior had previously been little studied. A clearly expressed depression of ammonia absorption in the 787-nm band was found in the Northern Equatorial Belt (NEB) of Jupiter. In the Great Red Spot, this band also exhibits substantial weakening. The position of the depression in the NEB is similar to that of the enhanced brightness temperature detected in the observations of the millimeter-wave radio emission, which is considered to be a result of the reduced ammonia content in this belt. At the same time, the weakening of the 787-nm band in the Red Spot is most likely caused by the enhanced bulk density of clouds, which influences the formation of absorption bands in the multiple scattering by cloud particles. The brightness temperature in the Red Spot is relatively low, as seen from observations in the radio and thermal IR ranges. We studied the spatial and temporal variations of the 645- and 787-nm bands in five belts of Jupiter: the Equatorial Zone (EZ), both Equatorial Belts (SEB and NEB), and both Tropical Zones (STZ and NTZ). The observations covered the time interval from 2005 to 2015, i.e., almost a complete orbital period of Jupiter. These observations confirmed the systematic character of the depression of the 787-nm band in the NEB and the difference in the latitudinal variations of the 645- and 787-nm bands. The latter can be related to features of the vertical distribution of the cloud density, which has a different influence on bands of different intensity.
关键词： spectrophotometry,molecular absorption,atmosphere,thermal radiation,clouds,ammonia,Great Red Spot,Jupiter
更新于2025-09-10 09:29:36
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Robust and accurate measurements of gold nanoparticle concentrations using UV-visible spectrophotometry
摘要： This paper provides an empirical formula to calculate the extinction efficiencies of gold nanoparticles over the size range 1–1000 nm in fluids with refractive indexes which extend from n = 1 to n = 1.62. The formula contains a shape factor to account for nonspherical particles and aggregates. The empirical curves are fitted to values calculated from accurate Mie and T-Matrix theory and confirm previous descriptions which are restricted to nearly spherical particles in water of diameter between 5 and 100 nm. This paper demonstrates that these previous descriptions will be in error for fluids other than water and for nonspherical particles greater than 100 nm in size. An empirical description is provided which matches calculated values to within a few percent across most of the range. The description also matches experimental data to within the standard relative error, currently 5% at best, using other methods which directly measure the particle concentration. These extinction efficiencies can be used to validate the concentration of gold nanoparticles in a wide range of situations to support the drive for reproducibility in nanoparticle research.
关键词： Mie theory,extinction efficiencies,gold nanoparticles,T-Matrix theory,UV-visible spectrophotometry
更新于2025-09-10 09:29:36
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DIRECT SPECTROPHOTOMETRIC DETERMINATION OF ATENOLOL AND TIMOLOL ANTI-HYPERTENSIVE DRUGS
摘要： Objective: Direct and sensitive spectrophotometric method is described for the quantitative determination of some anti-hypertensive drugs such as atenolol (ATN) and timolol (TIM) in pure forms as well as in their dosage forms. Methods: The proposed method is based on the redox reaction between the selected drugs and KMnO4 in alkaline medium. The method involves treating the aqueous solution of the selected drugs with KMnO4 in alkaline medium and measuring the bluish-green product at 610 nm. The different experimental parameters affecting the development and stability of the color were carefully studied and optimized. Results: The fixed-time method is adopted for constructing the calibration curves, which were found to be linear over the concentration ranges of 2.0–14 m g/ml and 2.0–28 m g/ml for ATN and TIM, respectively. The determination of the studied drugs by initial rate, variable time and rate constant method was workable with the calibration equations obtained but the fixed time method has been found to be more applicable. Conclusion: The applicability of the proposed method was demonstrated by the determination of the selected drugs in both pure and in commercial dosage forms and has met the validation requirements.
关键词： Spectrophotometry,Timolol,Atenolol,Dosage forms,Potassium permanganate
更新于2025-09-10 09:29:36
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PHYTOSYNTHESIS OF SILVER NANOPARTICLES USING E. CAMALDULENSIS LEAF EXTRACT AND THEIR CHARACTERIZATION
摘要： Herein, we report a simple green synthesis of silver nanoparticles (Ag NPs) by the reduction of aqueous silver salt solution using leaf broth of Eucalyptus camaldulensis. The profile of synthesized silver nanoparticles was evaluated by using UV-visible spectrophotometer, X-ray diffractometer, atomic force microscope, energy-dispersive X-ray spectroscope and scanning electron microscope. Surface plasmon resonance peak of silver nanoparticles appeared at 425 nm in UV-vis spectra of silver nanoparticles. XRD studies clearly confirmed the crystalline nature of the synthesized nanoparticles. The EDX analysis disclosed the arranged inorganic composition of the synthesized Ag NPs. Atomic force microscopy investigation revealed 3D surface profile of nanoparticles. From the SEM images, the silver nanoparticles were found to be more or less spherical with an average diameter range of 110-250 nanometers.
关键词： E. camaldulensis,SEM,AFM,UV-visible spectrophotometry,XRD,Ag NPs
更新于2025-09-10 09:29:36
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Investigations of properties of opal-like photonic crystals using combined methods
摘要： We propose a technique that combines atomic force microscopy, optical spectrophotometry and di?raction method for characterization of photonic crystals. These materials are promising for the creation of various devices, as well as for the observation of new e?ects due to their unique properties. Photonic crystals were synthesized by self-assembly of colloidal silica particles with low deviation in size. It is shown that the developed technique allows to increase the accuracy of determining the parameters of the photonic crystal.
关键词： diffraction method,photonic crystals,self-assembly,colloidal silica particles,atomic force microscopy,optical spectrophotometry
更新于2025-09-09 09:28:46
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Review of instrumental inter-agreement study of spectral and colorimetric data of commercial multiangle spectrophotometers
摘要： Several different instruments have been introduced into the market to obtain good color characterization for different measurement configurations. These commercial instruments have different optical and working configurations, however, the measurement data provided by each instrument should be similar to have good consistency when comparing them to each other measuring the same sample material. Therefore, the purpose of this work was to apply an inter-model agreement study of spectral and colorimetric data of three instruments (CM-M6, BYK-mac-I, and MA98). Two different statistical tests were applied following ASTM recommendations. In general, the measurement geometries close to the specular direction and the flop direction showed greater deviations. In addition, the partial color differences calculated for the comparison of MA98 versus CM-M6 were larger than the BYK-mac-i versus CM-M6 comparison. Finally, it can be concluded that most of the measurement geometries were statistically significantly different from each other which means that these differences were due to systematic or bias errors and not exclusively to random errors.
关键词： inter-model-agreement,color measurement,goniochromatism,spectrophotometry,reproducibility
更新于2025-09-09 09:28:46
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Personalized nanomedicine: a rapid, sensitive, and selective UV–vis spectrophotometry method for the quantification of nanostructured PEG-asparaginase activity in children’s plasma
摘要： PEGylated asparaginase (PEG-ASNase), which hydrolyzes asparagine to ammonia and aspartic acid, is an effective nanostructured antitumor agent for acute lymphoblastic leukemia (ALL). In order to monitor the activity of PEG-ASNase in plasma and design an individualization project, a rapid and sensitive method to determine PEG-ASNase activity in plasma using ultraviolet–visible spectrophotometry was established. Methods: PEG-ASNase is commonly used in acute lymphoblastic leukemia. With Nessler’s reagent as the chromogenic reagent of ammonia, a stable yellow complex was produced. The units of enzyme activity were defined as micromoles of ammonia released per minute. Results: Calibration curves fitted by plotting the OD at 450 nm of the Nessler product vs concentration were linear in the range of 27.8–1,111.0 IU/L with r2=0.999. The lower limit of quantification for PEG-ASNase activity in human plasma was 20 IU/L with good accuracy and precision. The intra- and interday precision (relative standard deviation) values were below 10% and accuracy ranged from 90% to 110% at all quality control levels. Analytical recoveries were determined between 90% and 110% for all quality control samples. Conclusion: This study proved that the Nessler method is well validated and can be successfully applied in the determination of plasma samples in the clinical setting for patients with ALL. It takes personalized nanomedicine to an entirely new level.
关键词： PEG-ASNase,plasma,ALL,enzyme activity,Nessler method,personalized nanomedicine,UV–vis spectrophotometry,Nessler’s reagent
更新于2025-09-09 09:28:46
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A new sensitive photometric procedure for the determination of sulfate in fuel ethanol without sample preparation exploiting a flow-batch strategy
摘要： A simple, accurate, and fast flow-batch procedure employing photometric detection for the determination of sulfate in fuel ethanol was developed. After the formation of soluble barium sulfate in alcoholic medium, the remaining barium forms a product with dimethylsulfonazo III (DMS), the absorbance of which was monitored at 655 nm directly in the reaction chamber. The proposed procedure does not require any sample treatment such as dilution. Under the optimized conditions, the technique offers the advantages of low waste generation (less than 5 mL), sampling throughput of 35 h-1, linear response from 0.1?1.5 mg L-1 sulfate, and a limit of detection (95%) and coefficient of variation (n = 6) of 48 μg L-1 and 1%, respectively. The accuracy was assessed by comparison of results with those obtained by ion-chromatography; no significant difference was observed at the 95% confidence level.
关键词： Arduino due,Fuel,Spectrophotometry,Bioethanol,Green chemistry,Barium sulfate
更新于2025-09-09 09:28:46