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Superior light harnessing and charge injection kinetics utilizing mirror-like nano cuboidal ceria coupled with reduced graphene oxide in zinc oxide nanoparticle based photovoltaics
摘要： Efficiency in nanoparticle based photovoltaics is limited by optical transparency, light absorption as well as detrimental back transfer of electron at the hetero-interfaces. Three dimensional (3D) micro/nanostructures with excellent light scattering properties play pivotal role in light harvesting efficiency in DSSCs. Present study deals with the design and development of ternary hybrid photoanode utilizing high quality mirror like nano-cuboidal ceria (CeO2 NC) and 2D- reduced graphene oxide (RGO) sheets in conjunction with ZnO nanoparticle. A ～6% power conversion efficiency has been achieved for photoanode with optimized CeO2 NC loaded with 1 wt% RGO into ZnO NP. CeO2 NC owing to its size and high quality mirror like facets provides a better light harvesting by multiple interactions of incident photon with the absorber as revealed by UV–Vis diffused reflectance and IPCE analysis. 2D- RGO is proposed to act as an electron sink and provides faster electron transport pathway. Inclusion of 2D- RGO sheets yields a better charge injection kinetics (keinj ～ 2.3 × 108 s?1 for ternary, 1.1 × 108 s?1 for reference device) and collection at FTO as well as elevated recombination resistance (Rrec) and photo-induced electron life time (τe), unveiled by Electrochemical Impedance Spectroscopic (EIS) analysis corroborates a reduced reverse tunneling of photo-injected electron at ZnO/sensitizer/redox couple interface.
关键词： Diffusion,Mirror-like,Light scattering material,Reduced graphene oxide,Electrochemical impedance spectroscopy,Nano cuboidal
更新于2025-11-21 11:01:37
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Electrochemical synthesis of Zn: ZnO/Ni2P and efficient photocatalytic degradation of Auramine O in aqueous solution under multi-variable experimental design optimization
摘要： Present work is devoted to synthesis Zn: ZnO/Ni2P by electrochemical method and identification and properties investigation by various techniques such as SEM, EDS, XRD and DRS. The experimental results reveal have ability for degradation of Auramine O (AO) following estimation of correlation among response to (main effect and variables interactions) variable like irradiation time, nanocomposite mass, pH and initial AO concentrations by a central composite design (CCD). The optimum condition for the photo-degradation of AO by photocatalyst was 6.72, 61.66 min, 13.13 mg.L-1 and 0.014 g correspond to the pH, irradiation time, AO concentration and photocatalyst mass, respectively. At these optimum conditions, the AO photocatalytic degradation percentages with desirability of 0.94 was 95.47% using reasonable consumption of reagent. The quasi first-order kinetic model derived from Langmuir–Hinshelwood (L–H) efficiently represent real behavior of experimental data of correspond to under study system. The photocatalytic reaction, L–H rate constants and L–H adsorption constants for Zn: ZnO/Ni2P were 0.0375 min-1, 27.39 mg.min-1.L and 0.00048 L.mg-1, respectively.
关键词： photocatalytic degradation,Auremine O,electrochemical synthesis.,Zn: ZnO/Ni2P,response surface methodology
更新于2025-11-21 11:01:37
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Electrochemical capacitance-voltage profiling of nonuniformly doped GaAs heterostructures with SQWs and MQWs for LED applications
摘要： Light-emitting heterostructures with single and multiple GaAs/InGaAs quantum wells have been investigated by means of electrochemical capacitance-voltage (ECV) profiling. Capacitance-voltage characteristics were measured; concentration profiles of free charge carriers over the heterostructure depth as well as the intensity of quantum well filling by charge carriers were obtained. In heterostructures with a single quantum well (QW) we considered limitations of capacitance techniques for undoped QW profiling, which is situated near the metallurgic border of the p–n –junction. We made a detailed consideration of phenomena related to Debye smearing and we developed and analyzed the dependence of the space charge region width on the doping. Special attention was paid to investigation of the “blind” area. This was inspired by the practical problem from capacitance spectroscopy of semiconductors, when the researcher poses the task of obtaining a free charge carrier depth distribution profile as deep as possible in the space charge region, i.e. where the intensity of the electric field is maximum. Generally, the active QW of a LED heterostructure is placed deep in the space charge region, so reaching these regions is extremely important for practical problems. We present an evolution of capacitance-voltage characteristics during ECV profiling of nonuniformly doped p – n– heterostructures. For a heterostructure with multiple quantum wells we registered a response from 6 QWs.
关键词： capacitance-voltage profiling,heterostructure,quantum well,nonuniform doping,Electrochemical capacitance-voltage profiling,quantum dot,light-emitting diodes
更新于2025-11-14 17:28:48
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Probing Electrocatalytic CO2 Reduction at Individual Cu Nanostructures via Optically Targeted Electrochemical Cell Microscopy
摘要： Optically targeted electrochemical cell microscopy (OTECCM) was applied to measure electrocatalytic rates at individual Cu nanoparticles (NPs) under electrolyte conditions relevant to CO2 reduction. The electrocatalytic responses from individual NPs were found to exhibit a wide variation in behavior, with significant NP-to-NP variations in the magnitude of electrocatalytic currents and necessary overpotentials being observed. Correlations of these quantities with metrics of NP size suggest no significant variations in the inherent electrocatalytic activity of the NPs with size. Finite element simulations of diffusion in this system demonstrate the observed diffusion-limited currents are significantly smaller than expected, attributable to the presence of a significant amount of residual ligand on the surface of the Cu NPs, which were prepared via an organic phase synthesis. The results presented here further demonstrate the promise of techniques which employ correlated optical and electrochemical measurements, such as OTECCM, for studying electrocatalysis at individual NPs.
关键词： Nanoparticles,Electrochemical microscopy,Electrochemistry,CO2 reduction
更新于2025-11-14 17:03:37
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N-arylated bisferrocene pyrazole for dual-mode detection of hydrogen peroxide: AIE-active fluorescent “turn on/off” and electrochemical non-enzymatic sensor
摘要： A series of new N?arylated bisferrocene pyrazole (D-π-A-π-D) chromophores have been synthesized by the Chan?Lam cross-coupling (1, 2) and Buchwald–Hartwig amination (3, 4) reactions. The compounds 1-4 were characterized with the aid of analytical and spectroscopic methods. The solvatochromism behaviour of compounds (1, 3) showed positive solvatochromism and later (2, 4) exhibited negative solvatochromism. The compounds 1-4 interestingly showcased high-enhanced fluorescent intensity in their aggregate state while in the solution state they exhibited low fluorescent intensity behaviour. The origin of enhanced emission in the aggregated state is due to a restriction of intramolecular rotation, especially in the ratio of mixture 40:60 (CH3CN/H2O). The aggregation-induced emission(AIE) properties were utilized to detect the H2O2 which show quick response in a linear range of 10-50 μM with a detection limit of 38.8 nM (1) and 15.9 nM (3). Furthermore, the electrochemical reduction of hydrogen peroxide in the same linear range as above showed and a limit of detection (3σ) of 14.4 mM (1) and 11.6 mM (3).
关键词： Dual-mode detection of H2O2,Electrochemical non?enzymatic sensor,AIE-active luminogens
更新于2025-11-14 15:29:11
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Synthesis, characterization, optical and electrochemical band gaps of green poly(azomethine-ester)s containing oxalyl and succinyl units
摘要： A new series of poly(azomethine-ester)s (PAZ-E)s with different (turning ortho, meta and para) positions were synthesized by condensation polymerization. The chemical structure of polymers was veri?ed by 1H-NMR, 13C-NMR, FTIR and UV–Vis measurements. Electrochemical characteristics of the corresponding polymers were obtained with cyclic voltammetric (CV) analysis. Thermal characteristics of the obtained polymers were analysed by TG-DTA, DMA and DSC measurements. The ?rst degradation temperature values of PAZ-E compounds were found between 198 and 250?C from TGA measurements. Photophysical characteristics of the obtained polymers were explained with photoluminescence (PL) spectroscopy. Molecular weight distributions of (PAZ-E)s were obtained by gel permeation chromatographic (GPC) analysis. Two- and three-dimensional (2D and 3D) properties and images of the synthesized (PAZ-E)s were analysed by SEM and AFM surface analysis techniques, respectively. Electrochemical band gap (E g) values of (PAZ-E)s P-9, P-10, P-11, P-12, P-13 and P-14 were calculated as 2.58, 2.14, 1.90, 2.06, 1.89 and 1.69 eV, respectively. The E g values of the (PAZ-E)s were found to be quite low.
关键词： surface morphologies,Poly(azomethine-ester),electrochemical properties,photophysical behaviour,schiff base,thermal degradation
更新于2025-11-14 15:26:12
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Electrochemical and surface deformation studies on electrodeposited nanostructured Bi2Te3 thin films
摘要： In this article, we have used double exposure digital holographic interferometry (DEDHI) technique for surface deformation study and hologram recording during synthesis of the Bi2Te3 thin films by electrodeposition method. The synthesized Bi2Te3 thin films were characterized structural, morphological, electrochemical, wettability and surface deformation study. Further the holograms are recorded during the electrodeposition process by varying the concentration of electrolyte. From the recorded fringes the stress, deposited mass and thickness have been calculated. It is observed that the fringe width, mass of deposited thin films, and stress to substrate changes with the concentration of electrolyte. The DEDHI technique is found more reliable for thickness measurement in electrodeposition process. The EIS study confirms that the deposited material is highly conducting.
关键词： Bi2Te3,EIS,Holography,DEDHI,Electrochemical properties,Electrodeposition
更新于2025-11-14 15:16:37
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Influence of Electrochemical Hydrogenation on the Circular Photocurrent in the Ag/Pd Nanocomposite
摘要： This work reports on a circular photocurrent in Ag/Pd nanocomposite films. The films, containing metal (Ag-Pd) and semiconductor (PdO) nanocrystallites in amorphous lead-silicate glass, are modified by electrochemical hydrogenation in a sulfuric acid solution. The photocurrent in the modified nanocomposite films is excited by nanosecond laser pulses at wavelengths of 532, 1064, and 1550 nm. In order to determine the circular and linear contributions in a transverse photocurrent, the dependences of the photocurrent on the degree of circular polarization of the exciting radiation are investigated. It is found that the electrochemical hydrogenation modification leads to a significant decrease of the electrical resistance and the polarization-sensitive transverse photocurrent in the films. It is also found that electrochemical hydrogenation significantly affects the ratio of the circular and the linear photocurrent components. The photocurrent is found to be generated on the subsurface layer of the films in the absence of crystalline phase component PdO.
关键词： circular photocurrent,Ag/Pd nanocomposite,electrochemical hydrogenation
更新于2025-11-14 15:13:28
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Mo/CIGS/CdS Structures by E‐ALD
摘要： The chalcopyrite CuIn(1-x)GaxSe2 (CIGS) thin films and their cadmium sulfide (CdS) window layer structures (CIGS/CdS) were grown on Mo foil substrate in layer-by-layer fashion by electrochemical atomic layer deposition (E-ALD) and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and photoelectrochemical (PEC) activity. XRD shows distinct pattern changes from chalcopyrite to chalcopyrite plus CdS structures upon adding E-ALD CdS layer to CIGS layers on Mo substrate. SEM shows that uniform and homogeneously distributed nanoparticles of CdS formed on top of CIGS layers, and EDS shows the successful preparation of CIGS/CdS structures with good atomic ratios in each layer. PEC performance reveals that bare CIGS films were of p-type conductivity but that CIGS/CdS structures n-type with p-type response near null.
关键词： Photoelectrochemistry,CuIn(1-x)GaxSe2/cadmium sulfide,Chalcopyrites,Electrochemical atomic layer deposition
更新于2025-11-14 14:48:53
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Anti-Reflecting Absorbing Layers for Electrochemical and Biophotonic Applications
摘要： Anti-reflecting layers deposited on flat surfaces make molecular films visible in reflecting light microscopy. For centuries, single Anti-Reflecting layers have been implicitly associated with dielectric materials. We recently demonstrated that anti-reflecting layers could be achieved out of absorbing materials such as metals as well, but only when used as backside layers where illumination and detection are performed through a supporting window. Fortunately, this corresponds to the best geometry when envisaging biophotonic or electrochemical applications at the solid/liquid interface. Here we explain how single absorbing anti-reflecting layers can serve each of these applications, and both simultaneously.
关键词： Biophotonic,Zeolites,Anti-Reflecting,Electrochemical,applications
更新于2025-09-23 15:23:52