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Fast Growth of Thin MAPbI <sub/>3</sub> Crystal Wafers on Aqueous Solution Surface for Efficient Lateral-Structure Perovskite Solar Cells
摘要： Fast Growth of Thin MAPbI3 Crystal Wafers on Aqueous Solution Surface for Efficient Lateral-Structure Perovskite Solar Cells
关键词： aqueous solution,lateral structure,perovskite solar cells,crystal wafer,fast growth
更新于2025-10-22 19:40:53
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Chemical Sensing Performance of Flower-Like ZnO/PSi Nanostructures via Electrochemical Impedance Spectroscopy Technique
摘要： ZnO nanostructures were synthesized on porous Si (PSi) structures using a method developed by this study known as electric field-assisted aqueous solution technique. The detailed characterization of this nanostructure was performed using atomic force microscopy, field emission scanning electron microscopy, x-ray diffraction, room-temperature photoluminescence and Raman spectroscopy. Electrochemical impedance spectroscopy (EIS) technique was used to detect two classifications of chemical solvents, namely polar and non-polar solvents. Nyquist plots in EIS were utilized to detect chemical solvents (ethanol, acetone, toluene and benzene) exposed to ZnO/PSi nanostructure arrays. The results showed that the grown flower-like ZnO nanostructure arrays served as good chemical sensors with high sensitivity and low power consumption. Meanwhile, the ZnO/PSi nanoflowers exposed to ethanol showed the highest sensitivity (94.6% response) compared to other chemical solutions with the least response exhibited by benzene (68.4% response). It was postulated that the interaction between the solution and oxygen species of ZnO/PSi nanostructure surface induced a resistance change resulting in the release of free electrons that migrated to the conduction band of ZnO/PSi nanoflower structures and reduced the number of surface-adsorbed oxygen species. Subsequently, the changes observed in the Nyquist semicircle diameter and Warburg impedance led to the chemical sensing response.
关键词： ZnO/PSi nanoflower,electric field-assisted aqueous solution technique,Chemical sensors,electrochemical impedance spectroscopy,Nyquist plot
更新于2025-09-23 15:23:52
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A turn-on reactive fluorescent probe for Hg2+ in 100% aqueous solution
摘要： It is an effective and precise strategy to design the fluorescence probe for Hg2+ based on a new specific reaction. A novel turn-on fluorescent probe, 4-{2-[4-(2-Mercapto-benzoyloxy)-phenyl]-vinyl}-1-methyl-pyridinium[e]iodide (MBPVP) for Hg2+ was developed. The mechanism was based on Hg2+-mediated ester hydrolysis to release the fluorophore, 4-[2-(4-Hydroxy-phenyl)-vinyl]-1-methyl-pyridinium[e]iodide, which showed outstanding intramolecular charge transfer (ICT) and the yellow-green fluorescence were observed. The turn-on probe showed rapid response time, outstanding selectivity and sensitivity for Hg2+ over other metal ions in 100% PBS buffer (pH = 7.4). The linear range was 2-16 μM and the detection limit was 6.5 nM. Furthermore, MBPVP was used to determine Hg2+ in real samples and in the solid state.
关键词： Hg2+,ester hydrolysis,MBPVP,100% aqueous solution,fluorescent probe
更新于2025-09-23 15:23:52
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An Ellipsometric Technique with an ATR Module and a Monochromatic Source of Radiation for Measurement of Optical Constants of Liquids in the Terahertz Range
摘要： Measuring the optical constants of liquids, especially water-containing solutions, is very difficult in the terahertz range. The well-known methods of measurement of the refractive index and absorption coefficient in this range include time-domain spectroscopy and Fourier-transform spectrometry. We have developed a highly sensitive ellipsometry method for measuring the optical constants of liquids using the tunable monochromatic radiation from the Novosibirsk free-electron laser. The ellipsometer is supplemented with an internal reflection module for the measurement of highly absorbing samples. The angle of incidence on the sample in the silicon prism of the module has been optimized for maximum sensitivity to parameters to measure. Measurements of the optical constants of various liquids have been performed, and a sensitivity of 0.01 has been demonstrated.
关键词： Internal reflection ellipsometry,Free electron laser,Aqueous solution,Terahertz range
更新于2025-09-23 15:21:21
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Aqueous Sn-S Complex Derived Electron Selective Layer for Perovskite Solar Cells
摘要： A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs). The tin and sulfur powder were directly dissolved in a (NH4)2S water solution to form Sn-S precursor. After depositon and annealing, the SnO2 film was formed, presenting as a low cost and enviromental friendly method for preparation of ESL. The films showed excellent transmittance at visible wavelength range. Moreover, the method exhibited high compatibility for doping using Cu, Cd, Li, and Zn elements. Zn doping (0.05 M) in the as-prepared SnO2 ESL significantly improved perovskite solar cells (PSCs) performance. The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO2 ESL samples. TiCl4 modifications on SnO2 film improved photovoltaic performance to 14.45%, but resulted in the poor long-term stability, around 80% more degredation than that of PSCs based on Zn-doped SnO2 films.
关键词： SnO2,Sn-S complex,aqueous solution,perovskite solar cell,electron selective layer
更新于2025-09-23 15:21:01
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Raman and infrared spectroscopic quantification of the carbonate concentration in K2CO3 aqueous solutions with water as an internal standard
摘要： Carbonate-bearing fluids widely exist in different geological settings, and play important roles in transporting some elements such as the rare earth elements. They may be trapped as large or small fluid inclusions (with the size down to <1 μm sometimes), and record critical physical-chemical signals for the formations of their host minerals. Spectroscopic methods like Raman spectroscopy and infrared spectroscopy have been proposed as effective methods to quantify the carbonate concentrations of these fluid inclusions. Although they have some great technical advantages over the conventional microthermometry method, there are still some technical difficulties to overcome before they can be routinely used to solve relevant geological problems. The typical limitations include their interlaboratory difference and poor performance on micro fluid inclusions. This study prepared standard ion-distilled water and K2CO3 aqueous solutions at different molarities (from 0.5 to 5.5 mol/L), measured densities, collected Raman and infrared spectra, and explored correlations between the K2CO3 molarity and the spectroscopic features at ambient P-T conditions. The result confirms that the Raman O-H stretching mode can be used as an internal standard to determine the carbonate concentrations despite some significant differences among the correlations, established in different laboratories, between the relative Raman intensity of the C-O symmetric stretching mode and that of the O-H stretching mode. It further reveals that the interlaboratory difference can be readily removed by performing one high-quality calibration experiment, provided that later quantifying analyses are conducted using the same Raman spectrometer with the same analytical conditions. Our infrared absorption data were collected from thin fluid films (thickness less than ~2 μm) formed by pressing the prepared solutions in a Microcompression Cell with two diamond-II plates. The data show that both the O-H stretching mode and the O-H bending mode can be used as internal standards to determine the carbonate concentrations. Since the IR signals of the C-O antisymmetric stretching vibration of the CO3 2- ion, and the O-H stretching and bending vibrations from our thin films are very strong, their relative IR absorbance intensity, if well calibrated, can be used to investigate the micron-sized carbonate-bearing aqueous fluid inclusions. This study establishes the first calibration of this kind, which may have some applications. Additionally, our spectroscopic data suggest that as the K2CO3 concentration increases the aqueous solution forms more large water molecule clusters via more intense hydrogen-bonding. This process may significantly alter the physical and chemical behavior of the fluids.
关键词： Relative IR absorbance,K2CO3 concentration,Relative Raman intensity,Carbonate aqueous solution,Micro fluid inclusion
更新于2025-09-23 15:19:57
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Silsesquioxane-Polythiophene Hybrid Copolymer as an Efficient Modifier for Single-Walled Carbon Nanotubes
摘要： One silsesquioxane-polythiophene hybrid copolymer, with combined star-like structure and intramolecular heterogeneity, was synthesized and sufficiently characterized via various methods, including FTIR, NMR, and SEC measurements. According to the exploration and characterization results, it was much more efficient at modifying SWNTs than its linear analogs in aqueous solution. The hydrophobic silsesquioxane core and PEDOT chains could locally anchor to the surface of the nanotubes, while the soluble flexible copolymer chains extended into the solution and rigid conjugated chains provided some π-π stacking effect to enhance adhesive force with the conjugated structure of the carbon nanotube, imparting steric stabilization to nanotube dispersion. The noncovalent interaction with SWNTs and solubility in aqueous solution improved the electrochemical characteristics of the modified-SWNT composite and availed for the preparation of a flexible and transparent electroactive film. Accordingly, this kind of silsesquioxane-polythiophene hybrid copolymer will be forwarded to apply to the assembling of flexible optoelectronic devices.
关键词： silsesquioxane-polythiophene hybrid copolymer,single-walled carbon nanotubes,noncovalent modification,electrochemical characteristics,aqueous solution
更新于2025-09-23 15:19:57
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Infrared Spectroscopic and Kinetic Characterization on the Photolysis of Nitrite in Alcohol-Containing Aqueous Solutions
摘要： Nitrite is regarded as a potential OH and NO precursor in aqueous solution upon ultraviolet photolysis. A step-scan Fourier-transform interferometer was employed to collect the transient infrared difference spectra upon excitation of the sodium nitrite aqueous solution in the presence of methanol and ethanol upon 355 nm pulsed excitation. The photolytic intermediates were proposed to be NO and NO2 via the direct dissociation from NO2? and the rapid reaction of OH and NO2?, respectively. Coupled with the theoretical calculations of the absolute energies and harmonic wavenumbers of relevant species using B3LYP density functional theory with the C-PCM model to account for the medium effect of H2O, a transient band at 1860?2030 cm?1 could be attributed to dissolved N2O3 isomers that could be quickly generated from NO + NO2. On the basis of the predicted thermodynamics, the reactions of alcohols with N2O3 were less thermodynamically favorable than that of water, resulting in a slightly decelerated depletion rate of N2O3 in alcohol-containing aqueous solution. Comparing the transient population of N2O3 in the absence and presence of CH3OH or C2H5OH, the upper-bound bimolecular rate coefficient of NO or NO2 with alcohols is reported as 7.3 × 103 M?1 s?1 for the first time. The spectroscopic and kinetic evidence of the reactivity of alcohols with NO, NO2, and N2O3 are provided to augment the roles of alcohols and NxOy in solution or in aqueous aerosol photochemistry.
关键词： Alcohols,Kinetics,Nitrite,Infrared spectroscopy,Aqueous solution,Photolysis
更新于2025-09-23 15:19:57
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A combined experimental and theoretical study of optical rotatory dispersion for ( <i>R</i> )-glycidyl methyl ether in aqueous solution
摘要： The dispersive optical activity for aqueous solutions of non-rigid (R)-glycidyl methyl ether (R-GME) has been explored synergistically from experimental and theoretical perspectives. Density functional theory analyses performed with the polarizable continuum model for implicit solvation identified nine low-lying stable conformers that are interconverted by rotation about two large-amplitude torsional coordinates. The antagonistic chiroptical signatures predicted for these structural isomers were averaged under a Boltzmann-weighting ansatz to estimate the behavior expected for a thermally equilibrated ensemble. This led to optical rotatory dispersion profiles that reproduced the overall shape of observations but failed to achieve uniform agreement with measured specific-rotation values even when anharmonic vibrational corrections were applied. A mixed QM/FQ paradigm, whereby quantum-mechanical (QM) calculations of optical activity were combined with classical molecular dynamics simulations of explicit solvation that included mutual-polarization effects by means of fluctuating charges (FQ), was enlisted to elucidate the microsolvation environment and gauge its impact upon conformer distributions and response properties. Although quantitative accord with experiments remained elusive, this approach revealed strong variations in the magnitude and sign of rotatory powers for R-GME as the configuration of surrounding water molecules evolved, thereby highlighting the inherently dynamical nature of the solvated chiroptical response, calling into question the validity of ''static'' descriptions based on the presumption of distinct energy minima, and giving insight into the inherent complexity posed by the modeling of such properties for solvated systems.
关键词： aqueous solution,fluctuating charges,molecular dynamics,(R)-glycidyl methyl ether,chiroptical properties,polarizable continuum model,optical rotatory dispersion,density functional theory
更新于2025-09-19 17:15:36
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Facile synthesis and color conversion of Cu-doped ZnSe quantum dots in an aqueous solution
摘要： A facile growth-doping method in aqueous solution has been developed to synthesize Cu-doped ZnSe (ZnSe:Cu) QDs by using thioglycolic acid (TGA) as a stabilizer. The effects of the Cu doping concentration, reaction temperature and pH value on the synthesis of ZnSe:Cu QDs were investigated systematically. The as-synthesized ZnSe:Cu QDs with an excellent green emission still belong to a cubic zinc blende crystalline structure, and the average particle size is approximately 3.0 nm. The photoluminescent quantum yield (PLQY) is as high as 20%, and the exciton radiative lifetime is approximately 113.8 ns. Moreover, the patterned ZnSe:Cu QDs thin films have been successfully fabricated by using an inkjet printing method to verify the ability of the potential application to the color conversion. With the assistance of 5.5 pair distributed bragg reflector (DBR) structures, the color coordinate of the ZnSe:Cu QDs thin film excited by the blue LEDs is located at (0.2182, 0.4352) and the intensity of PL peak located at 513 nm reaches to be 45.1%. In addition, the PLQY of color conversion-based ZnSe:Cu QDs thin film is approximately 9.64%. Based on these results, ZnSe:Cu QDs are potentially useful for the fabrication of optoelectronic devices, especially QDs photoluminescence and electroluminescence.
关键词： color conversion,Cu-doped ZnSe QDs,photoluminescent quantum yield,inkjet printing,aqueous solution
更新于2025-09-16 10:30:52