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Effect of doping on thin film solar cell efficiency based on ZnMn2O4 nanocrystals
摘要： The present study reports, for the first time, a facile synthesis for ternary ZnMn2O4 nanocrystals synthesized by a simple and low cost two-phase method. Those nanocrystals were used on thin film solar cell as active absorber layer. The resulting nanocrystals were characterized by XRD, TEM, AFM-MFM, FTIR and JV characterization techniques to investigate the crystalline behavior, chemical composition, morphology and optical properties. Two phase method allows the successful synthesis of oleic acid (OA) capped ZnMn2O4 nanocrystals with 5-10 nm particle size. After doping of the ZnMn2O4 nanocrystals at different ratios with P3HT:PCBM, an enhancement was observed in the solar cell performances based on thin films. The power conversion efficiency of P3HT:PCBM-ZnMn2O4 thin film solar cell was investigated by J-V characteristic curve and as a result of this study, the highest efficiency was achieved as 3.27% with a doping ratio of 1%. Thus we believe that this work will open a new perspective to the synthesis of ZnMn2O4 materials for applications in the field of energy conversion systems.
关键词： Two Phase,Magnetic force microscopy,Zinc Manganese Oxide,ZnMn2O4
更新于2025-09-12 10:27:22
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Effect of Laser Beam Welding on the Cyclic Material Behavior of the Press-hardened Martensitic Chromium Steel X46Cr13
摘要： For the application of high-strength materials in welded joints, a point of principle is how the strength of the sheet metal is affected by cyclic loading and by welding. For the investigation of the cyclic material behavior of the press-hardened martensitic chromium steel X46Cr13, strain-controlled fatigue tests were performed and evaluated. The aim of compensating the limitations in the weldability of this press-hardened material is achieved by a reduced heat input of the laser beam welding and a defined heat treatment. The effect of laser beam welding on the fatigue properties is shown by the cyclic behavior of butt joints. The cyclic material behavior is the basis of strain-based fatigue assessment approaches. Both cyclic stress-strain curves and strain-life curves are used for the fatigue life estimation. No clear difference between the press-hardened base material and butt joints has been found in the cyclic stress-strain curves. Transient effects are found by comparison of hysteresis loops of the initial loading, at the cyclically stabilized state and at crack initiation. Cyclic hardening is concluded from the initial loading and the cyclically stabilized state. By comparison of strain-life curves, a difference in the number of cycles to crack initiation between the base material and butt joints is found. Cycles to crack initiation of butt joints tested under strain control result in over 50 % of the base material’s fatigue strength at 1·106 cycles to failure.
关键词： high manganese TWIP steels,high-strength steel,MnCr steels,butt joint,laser beam welding,Martensitic stainless steel,integral fatigue life estimation method,press-hardening,cyclic material behavior
更新于2025-09-12 10:27:22
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Monitoring of the Mechanism of Mn Ions Incorporation into Quantum Dots by Optical and EPR Spectroscopy
摘要： Synthesis of nanoparticles doped with various ions can significantly expand their functionality. The conditions of synthesis exert significant influence on the distribution nature of doped ions and therefore the physicochemical properties of nanoparticles. In this paper, a correlation between the conditions of synthesis of manganese-containing cadmium sulfide or zinc sulfide nanoparticles and their optical and magnetic properties is analyzed. Electron paramagnetic resonance was used to study the distribution of manganese ions in nanoparticles and the intensity of interaction between them depending on the conditions of synthesis of nanoparticles, the concentration of manganese, and the type of initial semiconductor. The increase of manganese concentration is shown to result in the formation of smaller CdS-based nanoparticles. Luminescent properties of nanoparticles were studied. The 580 nm peak, which is typical for manganese ions, becomes more distinguished with the increase of their concentration and the time of synthesis.
关键词： manganese,electron paramagnetic resonance (EPR),nanoparticles,quantum dots,zinc sulfide,cadmium sulfide,luminescence
更新于2025-09-12 10:27:22
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Infrared photodissociation spectroscopy of di-manganese oxide cluster cations
摘要： Infrared multiple-photon dissociation (IR-MPD) spectroscopy and density functional calculations have been employed to elucidate the geometric structure of a series of di-manganese oxide clusters Mn2Ox+ (x = 4–7). The theoretical exploration predicts that all investigated clusters contain a rhombus-like Mn2O2 core with up to four, terminally bound, oxygen atoms. The short Mn–O bond length of the terminal oxygen atoms of ～1.58 ? indicates triple bond character instead of oxyl radical formation. However, the IR-MPD spectra reveal that higher energy isomers with up to two O2 molecules η2-coordinated to the cluster core can be kinetically trapped under the given experimental conditions. In these complexes, all O2 units are activated to superoxide species. The sequential increase of the oxygen content in the cluster allows for a controlled increase of the positive charge localized on the Mn atoms reaching a maximum for Mn2O7+.
关键词： superoxide species,density functional theory,di-manganese oxide cluster cations,IR-MPD spectroscopy,Infrared photodissociation spectroscopy
更新于2025-09-12 10:27:22
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Manganese oxide nanofoam prepared by pulsed laser deposition for high performance supercapacitor electrodes
摘要： Manganese oxide nanofoam has been prepared by pulsed laser deposition, from a metallic Mn target in a 5 Torr pressure O2 buffer atmosphere. The as-prepared samples were heat-treated at different temperatures (300?C-500?C) in air. Both as-deposited and heat-treated samples have a high porosity foam-like morphology, as shown by Field Emission Scanning Electron Microscopy. High Resolution Transmission Electron Microscopy revealed that the nanofoam is composed by linked nanoparticles with slight crystallization and growth of the nanoparticles due to heat-treatment, which was confirmed by X-ray diffraction, Raman Spectroscopy and X-ray Photoelectron Spectroscopy. These techniques also showed a variable oxide composition upon heat treatment. The supercapacitive properties of manganese oxide nanofoam treated at 300?C exhibited a specific capacitance higher than 1000 F/g, in the 0 to +1.0 V potential range. After heat treatment at 400?C and 500?C, the specific capacitance decreased compared to that of the 300?C treated sample. An increase of about 130% in the initial capacitance was obtained after 500 cycles for this sample. However, it decreases to one third of the maximum value after 5000 cycles. The results shows that the obtained manganese oxide nanofoam has very high specific capacitance but need to improve the cycle stability.
关键词： microstructures,pulsed laser deposition,porous materials,supercapacitors,nanofoam,manganese oxides
更新于2025-09-11 14:15:04
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Pulsed Laser Deposition of Rocksalt Magnetic Binary Oxides
摘要： Magnetic binary oxides with the rocksalt structure constitute an important class of materials for potential applications as electronic or electrochemical devices. Moreover, they often become a theoretical playground, due to the simple electronic and crystal structures, in the quest for novel phenomena. For these possibilities to be realized, a necessary prerequisite would be to grow atomically ordered and controllably-strained binary oxides on proper substrates. Here we systematically explore the use of pulsed laser deposition technique (PLD) to grow three basic oxides that have rocksalt structure but different chemical stability in the ambient atmosphere: NiO (stable), MnO (metastable) and EuO (unstable). By tuning laser fluence FL, an epitaxial single-phase NiO thin-film growth can be achieved in a wide range of growth temperatures 10 ≤ TG ≤750 °C. At the lowest TG, the out-of-plane strain raises to 1.5%, which is five times higher than in NiO film grown at 750 °C. MnO thin films that had long-range order were successfully deposited on the MgO substrates after appropriate tuning of deposition parameters. The growth of MnO phase was strongly influenced by FL and the TG. EuO films with satisfactory quality were deposited by PLD after oxygen availability had been minimized. Synthesis of EuO thin films at rather low TG = 350 °C prevented thermally-driven lattice relaxation and allowed growth of strained films. Overall, PLD was a quick and reliable method to grow binary oxides with rocksalt structure in high quality that can satisfy requirements for applications and for basic research.
关键词： Thin films,Nickel monoxide,Long-range ordered,Manganese monoxide,Europium monoxide,Strain engineering
更新于2025-09-11 14:15:04
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Mn doped ZnO nano material: a highly visible light active photocatalyst for environmental abatment
摘要： Mn doped ZnO nano photocatalyst (MnDZ) was prepared via simple co-precipitation method. MnDZ catalyst was characterized by XRD, FT-IR, UV–Vis-DRS, FE-SEM and TEM. The FE-SEM images showed that the MnDZ have rod and sphere like morphology with a size ranged from 20 to 50 nm. The catalytic activities were tested for the degradation of Direct blue 71 under visible light irradiation. The catalyst found to be highly active under neutral pH range and exhibit pseudo-first-order kinetics. The reusability of the photocatalyst indicates that 93% of dye was degraded even upto 3rd cycles of use.
关键词： ZnO,recycle,manganese,visible light,photocatalyst
更新于2025-09-10 09:29:36
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Influence of Iodine Doping on the Structure, Morphology and Physical Properties of Manganese Phthalocyanine Thin Films
摘要： Doping with halide ions is a popular method to alter the properties of metal phthalocyanines (MPcs), particularly magnetic and electrical nature of organic semiconductors for applications in spintronic or electronic devices. Doping can cause a structural rearrangement in MPc packing and the physical properties may be correlated with molecular packing. Films of a planar and magnetic MPc, manganese(II)phthalocyanine (MnPc) is chosen for iodine doping study. The optical, magnetic and the electrical properties of pristine and iodine doped MnPc thin films are investigated and can be directly associated with their molecular structure. 2D grazing incidence Synchrotron X-ray diffraction reveals structural disorder in MnPc films upon iodine infusion induced by the reorientation of ordered, edge-on molecular configuration to tilted and face-on configurations in a random fashion. The film morphology changes accordingly, where in the uniform crystallites reorganize in a disordered manner. The ferromagnetic nature of the pristine film gets weakened due to iodine species and favors antiferromagnetic coupling. The study of electrical properties at room temperature by conducting atomic force microscopy reveals that the conductance is enhanced independently of the film thickness due to disorder induced by iodine inclusion.
关键词： Thin Films,Electrical properties,Structural rearrangement,Manganese Phthalocyanine,Iodine doping,Magnetic properties
更新于2025-09-09 09:28:46
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Lead‐Free Semiconductors: Soft Chemistry, Dimensionality Control, and Manganese‐Doping of Germanium Halide Perovskites
摘要： Lead halide perovskites have drawn enormous interest due to their exceptional photovoltaic and optoelectronic properties. However, the toxic heavy metal lead is harmful to humans and the environment resulting in a need for strategies to replace this toxic element. Herein, we report a facile aqueous synthesis of CsGeX3 (X = I, Br) perovskite nanocrystals with size control achieved by varying the cysteammonium halide ligand concentration. We observe a variety of morphologies including pyramidal, hexagonal, and spheroidal. CsGeX3 nanocrystals undergo a lattice expansion due to partial replacement of Cs+ with larger cysteNH3+ cations into the lattice. We successfully dope Mn2+ into the CsGeX3 lattice for the first time with incorporation up to 29% in bulk and 16% in nano samples. XRD peak shifts and EPR hyperfine splitting strongly indicate that Mn2+ is doped into the lattice. Our results introduce a new member to the lead-free halide perovskite family and set the fundamental stage for their use in optoelectronic devices.
关键词： Germanium Halide Perovskites,Manganese(II) Doping,Perovskite Phases,Lead Substitution,Perovskite Nanocrystals
更新于2025-09-09 09:28:46
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Manganese phosphinocarbodithioate for RAFT polymerisation with sunlight-induced chain end post-treatment
摘要： A new manganese RAFT agent of the formula Cp(CO)2MnP(Ph)2C(vS)SCH(CH3)Ph was synthesized in a good overall yield by a three-step reaction from cymantrene and diphenylphosphine as the main starting materials. This complex proved to be e?cient for the control of RAFT polymerisation of St, n-BA and DMAAm. The reaction course could be conveniently monitored by 31P NMR spectroscopy. The controlled character of these polymerisations and the integrity of the polymer chain ends were demonstrated by the synthesis of diblock copolymers of St and n-BA. In the case of long polymerisation times (i.e. for PSt), photo-induced polymer chain coupling reactions were detected. Importantly, removal of the Mn-RAFT-ω-chain end by visible light irradiation led to the formation of a monomodal SH-terminated PSt. These phenomena were evidenced by IR spectroscopy, SEC with RI and UV detection modes and by ESI mass spectrometry.
关键词： sunlight-induced chain end post-treatment,visible light irradiation,manganese phosphinocarbodithioate,RAFT polymerisation,diblock copolymers
更新于2025-09-04 15:30:14