A three‐step method for the deposition of CH3NH3PbI3 perovskite films with a high crystalline structure and large cuboid overlayer morphology is reported. The method includes PbI2 deposition, which is followed by dipping into a solution of C4H9NH3I (BAI) and (BA)2PbI4 perovskite formation. In the final step, the poorly thermodynamically stable (BA)2PbI4 phase converts into the more stable CH3NH3PbI3 perovskite by dipping into a solution of CH3NH3I. The final product is characterized by XRD, SEM, UV/Vis, and photoluminescence analysis methods. The experimental results indicate that the prepared perovskite has cuboids with high crystallinity and large sizes (up to 1 μm), as confirmed by XRD and SEM data. Photovoltaic investigations show that the three‐step method results in higher solar cell efficiency (15 % enhancement in efficiency) with a better reproducibility than the conventional two‐step deposition method. 相似文献
In this study, an extraction and preconcentration technique using solid-phase extraction (SPE) along with hollow fiber (HF) has been developed as an ultra-preconcentration technique for some triazole pesticides in aqueous samples. Triazole pesticides were employed as model compounds to assess the method and were monitored by gas chromatography-flame ionization detection (GC-FID). Initially, an aqueous solution of target analytes was passed through an RP-8 SPE cartridge and then the adsorbed analytes were eluted with μL amounts of toluene. The collected elute was slowly introduced into an HF that had one end blocked. This allowed precipitation inside the lumen and pores of the HF. Finally, the obtained HF was mounted on a home-made solid-phase microextraction syringe and entered into the GC injection port for thermal desorption-GC analysis. The effect of various experimental parameters including injection port temperature, desorption time, state of HF, washing solvent, elution solvent and its volume, sample volume, etc. were investigated for finding the optimum conditions. The calibration graphs were linear in the ranges of 2-1000 ng/mL (penconazole and hexaconazole), 5-1000 ng/mL (tebuconazole), 15-1000 ng/mL (triticonazole) and the detection limits (LODs) ranged from 0.6 to 4.5 ng/mL. The enhancement factors were in the range of 870-950. The relative standard deviations (RSD%) for five repeated experiments (C=250 ng/mL of each pesticide) varied from 4.5 to 8.7%. The relative recoveries obtained for analytes in grape juice samples, spiked with different levels of each pesticide, were in the range of 87-119%. 相似文献
The syntheses of three mixed ligand chelate copper(II) complexes of the type [Cu(L)(acac)(H2O)]BPh4 where acac=acetyleacetonate; L=N,N‐dimethyl,N′‐benzylethane‐1,2‐diamine ( L1 ), N,N‐dimethyl, N′‐2‐methylbenzylethane‐1,2‐diamine ( L2 ) or N,N‐dimethyl,N′‐2‐chlorobenzylethane‐1,2‐diamine ( L3 ) are reported and characterized by elemental analyses, spectroscopic and molar conductance measurements. The X‐ray structure of complex 1 shows that the central copper atom is placed in a distorted square pyramidal geometry made by acac and diamine chelate in the base and a H2O molecule on the apex. The prepared complexes are fairly soluble in a large number of organic solvents and show positive solvatochromism. Calculations of SMLR (stepwise multiple linear regression) method was utilized to find the best model explaining the observed solvatochromic behavior and showed that among different solvent parameters, donor number (DN) is a dominant factor responsible for the shift in the d‐d absorption band of the complexes to the lower wavenumber with increasing its values. The importance of substituent effect in diamine ligand on the spectral and SMLR measurements is also discussed. 相似文献
Nanoscale rifts and ripples at a periodicity of 130 nm were generated on Si(100) surfaces immersed in water using tightly focused 800 nm 12 fs pulsed 85 MHz laser light at subnanojoule pulse energies. At radiant exposure close to the ablation threshold rifts were typically 20-50 nm in width and 70 nm in depth running perpendicular to the laser polarization. On increase of the irradiance, the rifts broadened and formed periodic ripples, whereas at highest exposure, a random nanoporous surface topology emerged. Rift and ripple formation is explained by laser-induced standing surface plasma waves, which result in periodic variation of dissipation and ablation. 相似文献
A novel ZnS nanoparticle‐modified carbon paste electrode (ZnSNP‐MCPE) was fabricated and used to study the electrooxidation of thioridazine (TR) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The determination conditions, such as accumulation time, pH of solution, and modifier amount were optimized. The mechanism of the electrooxidation process on the surface of the modified electrode was studied electrochemically. A linear range of 0.1–36.0 µM with detection limit of 65.0 nM was obtained for TR. In a mixture containing TR and olanzapine (OLZ), the DPV peaks of two compounds can be well separate from each other with a potential difference of 425 mV. Finally, this method was successfully applied to determinate the TR content in real samples. 相似文献
Two di- and triorganotin (IV) complexes, Sn (CH3)2Cl2(4-PCAPh)2 ( C 1 ) and Sn(C6H5)3Cl(4-PCAPh) ( C 2 ); {4-PCAPh = 4-NC5H4C(O)NHP(O)(C6H12N)2}, have been synthesized and characterized by elemental analysis, 1H, 13C, 31P NMR and IR spectroscopy. The crystal structure of C 1 has been confirmed by X-ray crystallography, which reveals an octahedral geometry surrounding Sn (IV). Both ligands function in an all-trans conformation, with an N-ligated mode for 4-PCAPh. Also, the complexes were prepared at nano- ( Ć 1 ) and micro-size ( Ć 2 ) by the sonochemical process. The role of reaction solvent and the concentration of initial reactants on the size and morphology of particles were studied and the products were characterized by X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The activities and mechanism of complexes C 1 , C 2 , Ć 1 , Ć 2 and their corresponding ligand ( L ) on cholinesterase (ChE) were evaluated using a modified Ellman's method and Lineweaver-Burk plots. Nanosheet Ć 1 showed the best activity against AChE and BChE with the IC50 values being 73.08 ± 0.12 μM and 122.48 ± 0.69 μM, respectively, and the mixed-type mechanism. Molecular modeling simulation revealed the binding interaction template for Sn (CH3)2Cl2(4-PCAPh)2 with the ChE. 相似文献
Sodium sulfate‐induced deep eutectic solvent–based solidification of floating organic droplets–dispersive liquid phase microextraction was developed prior to gas chromatography–mass spectrometry. In this method, a mixture of Na2SO4 solution (as phase separation agent and disperser) containing menthol–decanoic acid was rapidly injected into an alkaline aqueous solution containing Na2SO4. The solution was placed in an ice bath and the menthol–decanoic acid solvent was solidified on the surface of the solution. Under the optimal conditions, the enrichment factors and extraction recoveries were 122–147 and 74–89%, respectively. Finally, an aliquot of the collected organic phase was removed and mixed with acetonitrile and injected into the separation system. The limits of detection and lower limits of quantification were obtained at the ranges of 13–25 and 24–41 ng L?1, respectively. The relative standard deviations of the proposed method were ≤11% for intra‐ and inter‐day precisions at four concentrations. 相似文献
N-Acetyl-N′-methyl urea or ethyl urea in the presence of an acetylenic ester and a desired phosphine functioned as a NH-acid and added to the triple bond in a chemoselective reaction. One of the obtained products underwent lactonization to the corresponding imidazolidine containing ylide moiety when heated in the presence of a base such as triethyl amine. 相似文献