99 research outputs found
Impact of coupled plasmonic effect with multishaped silver nanoparticles on efficiency of dye sensitized solar cells
No full textDye sensitized solar cells (DSSCs) have numerous advantages, but in order to use widespread industrial deployment we need to boost the power conversion efficiency. One promising approach to improve DSSC performance is to improve the spectral response of sensitizers with metal nanoparticle-based surface plasmon resonance. Even single shaped nanoparticles (NPs), however, have physical limitations. Thus, in this study a simple synthesis route is used to fabricate multishaped silver (Ag) NPs to create a coupled plasmonic effect in DSSC to cover more of the solar spectrum. The impact of multishaped AgNPs combinations are studied to determine which aspects improve the power conversion efficiency of DSSC. A detailed investigation was made of both the TiO2 (XRD) and AgNPs (UV–Vis spectrometry) to couple the impacts on the DSSC (I-V) with the combination of the morphologies (TEM and FESEM) of AgNPs. Synthesized AgNPs with distinct extinction cross section covers the visible and IR regime from 300 nm to 1100 nm by tuning its plasmonics band. It is inferred that multi-shaped AgNPs predominately enhance the light harvesting, charge separation and carrier transportation. The results show that the increment in short circuit current and open circuit voltage resulted in an increase of 45% overall power conversion efficiency in the standard DSSC device is attributed to the usage of multi-shaped AgNPs. Finally, a mechanism is proposed to support the outcome of the experiment by demonstrating the extinction cross section and the local field of the various shaped AgNPs using Finite-difference time-domain (FDTD) simulation
Effect of microwave power irradiation on TiO2 nano-structures and binder free paste screen printed dye sensitized solar cells
No full textTitanium dioxide (TiO2) nanostructures (nanorods and nanoparticles) were prepared using a low-cost microwave irradiation method from a polyol medium of glycerol. Titanium glycerolate and TiO2 powders were obtained in the glycerol medium for the first time with four different power densities (240 W, 480 W, 720 W, 960 W) of irradiation using a domestic microwave oven of 2.45 GHz, to understand the impact of power on morphology tuning. The structural and morphological features of the titanium glycerolate and TiO2 powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Raman spectra analysis. The TiO2 was successfully used in the fabrication of photovoltaic devices and as a proof-of-concept binder free paste was prepared and successfully employed for photo-anode using screen printing on the fluorine-doped tin oxide substrate.Peer reviewe
The Distal Part of the Transition Zone Is the Most Aluminum-Sensitive Apical Root Zone of Maize1
No full textAbstract
For a better understanding of Al inhibition of root elongation, knowledge of the morphological and functional organization of the root apex is a prerequisite. We developed a polyvinyl chloride-block technique to supply Al (90 μm monomeric Al) in a medium containing agarose to individual 1-mm root zones of intact seedlings of maize (Zea mays L. cv Lixis). Root elongation was measured during a period of 5 h. After Al treatment, callose (5 h) and Al (1 h) contents of individual 1-mm apical root segments were determined. For comparison, callose and Al levels were also measured in root segments after uniform Al supply in agarose blocks to the 10-mm root apex. Only applying Al to the three apical 1-mm root zones inhibited root elongation after 1 h. The order of sensitivity was 1 to 2 &gt; 0 to 1 &gt; 2 to 3 mm. In the 1- to 2-mm root zone high levels of Al-induced callose formation and accumulation of Al was found, independently of whether Al was applied to individual apical root zones or uniformly to the whole-root apex. We conclude from these results that the distal part of the transition zone of the root apex, where the cells are undergoing a preparatory phase for rapid elongation (F. Baluška, D. Volkmann, P.W. Barlow [1996] Plant Physiol 112: 3–4), is the primary target of Al in this Al-sensitive maize cultivar.</jats:p
Zoom-in to molecular mechanisms underlying root growth and function under heterogeneous soil environment and abiotic stresses.
No full textThe review describes tissue-specific and non-cell autonomous molecular responses regulating the root system architecture and function in plants. Phenotypic plasticity of roots relies on specific molecular and tissue specific responses towards local and microscale heterogeneity in edaphic factors. Unlike gravitropism, hydrotropism in Arabidopsis is regulated by MIZU KUSSIE1 (MIZ1)-dependent asymmetric distribution of cytokinin and activation of Arabidopsis response regulators, ARR16 and ARR17 on the lower water potential side of the root leading to higher cell division and root bending. The cortex specific role of Abscisic acid (ABA)-activated SNF1-related protein kinase 2.2 (SnRK2.2) and MIZ1 in elongation zone is emerging for hydrotropic curvature. Halotropism involves clathrin-mediated internalization of PIN FORMED 2 (PIN2) proteins at the side facing higher salt concentration in the root tip, and ABA-activated SnRK2.6 mediated phosphorylation of cortical microtubule-associated protein Spiral2-like (SP2L) in the root transition zone, which results in anisotropic cell expansion and root bending away from higher salt. In hydropatterning, Indole-3-acetic acid 3 (IAA3) interacts with SUMOylated-ARF7 (Auxin response factor 7) and prevents expression of Lateral organ boundaries-domain 16 (LBD16) in air-side of the root, while on wet side of the root, IAA3 cannot repress the non-SUMOylated-ARF7 thereby leading to LBD16 expression and lateral root development. In root vasculature, ABA induces expression of microRNA165/microRNA166 in endodermis, which moves into the stele to target class III Homeodomain leucine zipper protein (HD-ZIP III) mRNA in non-cell autonomous manner. The bidirectional gradient of microRNA165/6 and HD-ZIP III mRNA regulates xylem patterning under stress. Understanding the tissue specific molecular mechanisms regulating the root responses under heterogeneous and stress environments will help in designing climate-resilient crops. [Abstract copyright: © 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
pH Triggered Curcumin Release from PMMA-AA Coated ZnO Nanoparticles for Excellent Anti-Gastric Cancer Therapy
No full textDual morphology titanium dioxide for dye sensitized solar cells
No full textAnatase TiO2 displaying dual morphologies were synthesized with a simple chemical route via a single step. A strong correlation between the dye sensitized solar cell (DSSC) device performance and the obtained dual morphologies are highlighted using relevant evidences from UV–vis and diffuse reflectance spectroscopy (DRS), Raman analysis, field emission scanning electron microscope, high resolution transmission electron microscope, current-voltage characteristics and impedance analysis. Structural investigation revealed that the interested medium in this work employed for the synthesis of TiO2 produced different types of dual morphologies such as nanospheres with nanoparticles (NSNP), microsphere decorated with nanoparticles (μSNP) and nanoparticles with stone like features (NPS). UV–vis and DRS results indicated the ability of the materials to assist with diffused reflectance and optical absorption of the screen printed photoanodes. In addition, an investigation of Raman vibrational characteristics was carried out in detail using synchronous and asynchronous 2D correlation analysis. The high intense Eg anatase mode of Raman spectrum was simulated using a phonon confinement model and its normalized spectra are compared with an experimental data. The resultant performances in the DSSCs were not indicative by the material properties; so, the charge transfer resistance (Rct) and recombination properties of the photoanode were investigated. These results showed that the Nyquist plot of NSNP possesses the smallest diameter, which reveals that the device based on NSNP offers the lowest Rct value that accounts for the higher conversion efficiencies when compared with the DSSC device based on photoanodes μSNP and NSP. It can be concluded that the improved power conversion efficiency shown by photoanode fabricated using NSNP has the dual role of optimum surface area for dye loading and light scattering centres. These properties, when optimized along with the offered pathway for electrolyte diffusion to the dye degeneration with less Rct, could lead to better photoelectric conversion efficiency.Peer reviewe
Properties of Al-doped zinc oxide and In-doped zinc oxide bilayer transparent conducting oxides for solar cell applications
No full textInternational audienceNovel aluminum and indium doped zinc oxide bilayer transparent conducting oxide thin films have been developed by simple sol gel spin coating and annealed at 500 C for an hour under nitrogen ambient towards solar cell applications. The structural, electrical and optical properties of both the as deposited and annealed bilayer thin films are characterized. X-ray diffraction studies showed a hexagonal wurtzite-type structure of ZnO with (002) orientation, which was enhanced with annealing. In atomic force microscopy studies minimum surface roughness is attained for the Al-doped ZnO/In-doped ZnO bilayer TCO films. The best Al-doped ZnO/In-doped ZnO films had sheet resistance of 0.057 M ohm/square and the films had an average transmittance in the visible region over 90%. Further results are discussed with single and bilayer structure
Properties of Al-Doped Zinc Oxide and In-Doped Zinc Oxide Bilayer Transparent Conducting Oxides for Solar Cell Applications
No full textNovel aluminum and indium doped zinc oxide (ZnO) bilayer transparent conducting oxide thin films was fabricated by simple sol-gel spin coating method and post-annealed at 500 °C for an hour under nitrogen ambient for solar cell applications. The structural, electrical and optical properties of both the as-deposited and annealed bilayer thin films were characterized. X-ray diffraction studies show a hexagonal wurtzite-type structure of ZnO with (0 0 2) orientation, which enhanced with annealing. In atomic force microscopy studies, minimum surface roughness was attained for Al-doped ZnO (AZO)/In-doped ZnO (IZO) bilayer TCO film compared to IZO/AZO bilayer film. The AZO/IZO film sheet resistance improved to 0.057 M ohm/square after post-annealing, while the single layer AZO film sheet resistance degraded upon annealing in nitrogen atmosphere. All the films had an average transmittance in the visible region over 96%
Effects of silver catalyst concentration in metal assisted chemical etching of silicon
No full textA systematic investigation is performed to determine the effects of the concentration of silver on metal assisted chemical etching (MaCE) for nanostructure formation mechanisms on silicon as well as their resultant optical properties. Silver nitrate concentrations of 8 mM, 4 mM, 3 mM and 2 mM with hydrogen fluoride were used for the preparation of p-type silicon nanostructures. Experimentally, it is observed that when the catalysis molarity concentration is decreased in the etching processes, it resulted in nanostructures ranging from 140 to 60 nm, respectively over the concentrations investigated. A detailed analysis of the optical properties and structure provided insight into the physics of their formation. In addition, the results show the silicon nanostructures formed black silicon where in the visible region of the spectrum the reflectance dropped by an order of magnitude. The results indicate MaCE is a promising approach to the manufacturing of antireflection coatings on black silicon-based solar photovoltaic cells. MaCE is a simple and scalable approach to enhance the optical absorption of silicon and improve the overall efficiency of the solar cell without adding significantly to the complexity, capital expenditure or cost of production
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