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Formation of titanium carbide on the titanium surface using laser ablation in n-heptane and investigating its corrosion resistance
摘要： Laser ablation of titanium in liquid (LAL) using a fiber laser was studied. Firstly, LAL was carried out in toluene, n-hexane, n-heptane, and acetone as liquid media at the same irradiation conditions. Samples were characterized by different diagnostic techniques X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS). It was found that titanium carbide (TiC) structure has been generated on the surface of laser ablated samples in toluene, n-hexane, and n-heptane. Also, titanium dioxide was formed on the surface of laser ablated sample in acetone along with TiC. After that, n-heptane was chosen as the adequate liquid medium. LAL process was repeated in n-heptane for different ablation process times at the same irradiation conditions. Samples were investigated by XRD, Raman spectroscopy, EDS, nuclear reaction analysis (NRA), and cross sectional FESEM. It was concluded that the ablation process time of about 30 s is threshold time to form detectable TiC structure by XRD. Additionally, it was deduced that the amount of the carbon (in two forms of amorphous and carbidic) on the surface of the irradiated titanium for about 2 min (S8 sample) is more than other samples. The corrosion behavior of samples was studied by electrochemical impedance spectrometry (EIS) tests. The EIS plots obtained after 24, 48, 72, and 96 h immersion time showed the corrosion resistance of S8 sample enhancement in Ringer's solution compared with the other samples, and the corrosion resistance of this sample increased by rising the immersion time up to 96 h.
关键词： EIS.,titanium carbide,Ringer's solution,n-heptane,laser ablation,titanium
更新于2025-09-19 17:15:36
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Photoconversion efficiency of Titania solar cells co-sensitized with natural pigments from cochineal, papaya peel and microalga Scenedesmus obliquus
摘要： Three natural pigments obtained from cochineal, papaya peel, and the microalga Scenedesmus obliquus were tested as sensitizers in dye sensitized Titania solar cells. The absorption characteristics of the pigments and the photoelectrochemical parameters were studied to determine the photoconversion efficiency of the cells. The interfacial charge transport processes present in the individually sensitized and the co-sensitized cells were determined by electrochemical impedance spectroscopy (EIS). The highest efficiencies achieved for individual pigments after testing a set of different concentrations were 0.228, 0.093 and 0.064% using cochineal, papaya peel extract and Scenedesmus obliquus extract respectively. 0.36% conversion efficiency was reached in the sensitized cell using a combination of the three pigments. The efficiency reached is in the range of those reported for natural pigments. Papaya peel extract and chlorophylls from Scenedesmus obliquus were examined for the first time as possible sensitizers in DSSC.
关键词： photoelectrochemical parameters,energy conversion efficiency.,natural pigments,DSSC,mixed extracts,electrochemical impedance spectroscopy (EIS)
更新于2025-09-12 10:27:22
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Binary ionic liquid electrolytes for copper indium sulfide quantum dot sensitized-TiO2 solar cell to achieve long-term durability
摘要： This work demonstrates a straightforward strategy to develop the copper-indium-sul?de (CIS) quantum dot-sensitized solar cells (QDSSCs) consisting of ionic liquids (ILs) as electrolyte instead of any volatile solvent. The power conversion ef?ciency (PCE) of the solar cell yielded with 0.36% in the presence of 1-butyl-3-methylimidazolium sul?de ([BMIm][S2?/Sn2?]) and 1-butyl-3-methylimidazolium thiocyanate ([BMIm][SCN]) exhibited an improvement of JSC and FF yielding with 0.75% (JSC: 8.69 mA cm?2, VOC: 0.32 V, FF 26.8%). It exhibited long-term stability within 20% drops after 72 h-continuous photo-irradiation and subsequent storage for more than 1300 h in dark. It is due to suppression of the volatilization of solvent and decomposition of sul?de/polysul?de (S2?/Sn2?) anions. The solar cell performances were found to promote as an increase of interfacial charge transfer ef?ciency between electrolyte and electrodes by means of electrochemical impedance spectroscopy.
关键词： Electrochemical impedance spectroscopy (EIS),Power-conversion ef?ciency (PCE),Ionic liquid electrolyte,Quantum dot-sensitized solar cell,Copper indium-sul?de (CIS) colloids
更新于2025-09-12 10:27:22
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Influence of the Adsorption of Phycocyanin on the Performance in DSS Cells: and Electrochemical and QCM Evaluation
摘要： The influence of some coadsorbents and different pH values on the efficiency of DSS cells assembled with phycocyanin was evaluated using quartz crystal microbalance (QCM) and electrochemical techniques as impedance spectroscopy (EIS) and cyclic voltammetry (CV). Chlorophyll, heptadecanoic acid and 7.5 or 8.5 pH values were applied when nanostructured TiO2 electrode was dipped in the dye solution. Best efficiency conversion values were obtained when using fatty acids as coadsorbents, reaching a conversion efficiency of 0.04 % for open cells.
关键词： DSSC,QCM,coadsorbents,EIS,phycocyanin
更新于2025-09-10 09:29:36
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Al-doped ZnS thin films: Physical and electrochemical characterizations
摘要： This study evaluated the effect of Al incorporation on the structural, optical, electrical and electrochemical properties of ZnS thin films. An electrochemical route was used to synthesize the studied un- and Al-doped ZnS thin films on indium tin oxide (ITO) glass substrates using an aqueous solution of ZnCl2 and Na2S2O3. The Al-doped ZnS samples were prepared by adding different amounts of AlCl3 to the main electrolyte. Cyclic voltammetry determined (cid:1)0.9 to (cid:1)1.1 V as the appropriate potential range for deposition of the ZnS thin films. In addition, appearance of a new reduction peak in the cyclic voltammograms of the Al-doped ZnS samples approved the presence of the Al dopant in the structure of the electrodeposited films. The recorded X-ray diffraction (XRD) patterns exhibited that all deposited samples contain cubic ZnS crystals and indicated that Al-doping decreases the crystallite size of the ZnS samples. Field emission scanning electron microscopy (FESEM) demonstrated that all samples are composed of big grains with 150e600 nm dimension distributed in a background phase including 15e60 nm grains. The photoluminescence (PL) spectra showed that all samples emit five PL peaks due to their different crystal defects. UVeVis spectroscopy clarified that Al-doping decreases the band gap energy of the ZnS samples from 3.93 to 3.50 eV. Furthermore, it showed that the Al-doped ZnS samples present a lower capacitance and a shorter response time, which are suitable properties for application of these materials in fast photodetectors. The Mott-Schottky plots demonstrated n-type conductivity for all samples and revealed that the existence of the Al dopant increases the carrier concentration of the ZnS thin films. The electrochemical impedance spectroscopy (EIS) results confirmed that Al incorporation reduces the time constant and capacitance of the ZnS samples. Consequently, all results declared that Al incorporation has significant effects on the physical, optical and electrical properties of ZnS thin films.
关键词： EIS,Photoluminescence,Electrodeposition,Al incorporation,ZnS thin films
更新于2025-09-09 09:28:46
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Electrochemical Behavior of Titanium Nitride Thin Films Deposited on Silicon by Plasma Discharge Technique in Cathodic Cage
摘要： Titanium nitride films were deposited on silicon by plasma discharge in cathodic cage with holes and without holes on the sides. Each film was deposited with a pressure of 253 Pa, treatment time of 2 h, and at diverse conditions of temperature and gas flow of N2 and H2. The electrochemical polarization and electrochemical impedance techniques were used to understand the effect on the electrochemical properties of these films in relation to the presence or absence of holes on the sides of the cathodic cage and to investigate the electrochemical behavior of the films formed, which presented as both capacitive and resistive for the conditions analyzed.
关键词： thin films,cathodic cage,polarization,titanium nitride,EIS
更新于2025-09-09 09:28:46