Investigation of Various Nano-Structural Morphologies of Zinc Oxide for their Applications in Dye-Sensitized Solar Cells (original) (raw)
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Electrochimica Acta, 2008
In this work, the morphology of ZnO materials could be controlled by changing the capping agent at constant alkali solution in hydrothermal process. ZnO nanomaterials with the structure of flowers, sheet-spheres and plates were obtained with the capping agent of ammonia, citric acid and oxalic acid, respectively. Thus prepared ZnO nanomaterials were characterized and applied as the photo-anode materials for dye-sensitized solar cell. All synthesized ZnO nanomaterials possessed high crystalline wurtzite structures grown in the (0 0 1) direction with the size of 2-4 m, which consist of ZnO units around 20-400 nm. Among them, Sheet-sphere ZnO showed the highest crystallinity, surface area and uniform film morphology, resulting in the significantly improved PV performance with the overall conversion efficiency of 2.61% in dye-sensitized solar cell (DSSC) fabricated with sheet-sphere ZnO. It is notable that the ZnO materials with sphere structure may be the optimal photo-anode material among various ZnO nanomaterials for DSSC.
The Journal of Physical Chemistry C, 2013
ABSTRACT We report on the growth control of zinc oxide nanorods to point out the effect of the ZnO nanorods quality on the power conversion efficiency (PCE) of transparent conductive oxide (TCO)/ZnO nanorods/dye/spiro-OMeTAD/metal electrode photovoltaic devices. A promising PCE of 0.61% was measured for the best nanorods growth conditions. A careful control of all the growth parameters during the seeds layer deposition and the hydrothermal synthesis was necessary to reach such a high PCE for this kind of device. A regular nanorod layer with a flat upper surface was obtained for ethylenediamine to zinc acetate dihydrate molar ratio equal to 1.74 and a pH of 8.2. The growth was performed at 65 °C for 2 h to avoid zinc oxide brushes deposition on the surface, arising from zinc hydroxyacetate decomposition during the hydrothermal treatment. The effect of ZnO nanorods length (ranging from 1 to 3 μm) on solar cell efficiency was tested. Although the UV–vis absorption increases when the nanorods length increases, the best photovoltaic parameters were measured for the shortest nanorods length studied (1 μm).
Journal of Nanoscience and Nanotechnology, 2011
This article reports a facile growth of well-crystalline aligned hexagonal ZnO nanorods on fluorinedoped tin-oxide (FTO) substrate via non-catalytic thermal evaporation process. The morphological investigations done by field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) reveal that the grown products are aligned hexagonal ZnO nanorods which are grown in a very high density over the whole substrate surface. The detailed structural properties observed by high-resolution TEM equipped with selected area electron diffraction (SAED) and X-ray diffraction (XRD) pattern confirmed that the synthesized nanorods are well-crystalline possessing wurtzite hexagonal phase and preferentially grown along the c-axis direction. A sharp and strong UV emission at 381 nm in room-temperature photoluminescence (PL) spectrum showed that the as-grown ZnO nanorods possess excellent optical properties. The as-grown nanorods were used as photo-anode for the fabrication of dye-sensitized solar cells (DSSCs) which exhibits an overall light-to-electricity conversion efficiency (ECE) of 0.7% with V OC of 0.571 V, J SC of 2.02 mA/cm 2 and FF of 0.58.
Direct Growth of Flower-Shaped ZnO Nanostructures on FTO Substrate for Dye-Sensitized Solar Cells
Crystals, 2019
The proposed work reports that ZnO nanoflowers were grown on fluorine-doped tin oxide (FTO) substrates via a solution process at low temperature. The high purity and well-crystalline behavior of ZnO nanoflowers were established by X-ray diffraction. The morphological characteristics of ZnO nanoflowers were clearly revealed that the grown flower structures were in high density with 3D floral structure comprising of small rods assembled as petals. Using UV absorption and Raman spectroscopy, the optical and structural properties of the ZnO nanoflowers were studied. The photoelectrochemical properties of the ZnO nanoflowers were studied by utilizing as a photoanode for the manufacture of dye-sensitized solar cells (DSSCs). The fabricated DSSC with ZnO nanoflowers photoanode attained reasonable overall conversion efficiency of ~1.40% and a short-circuit current density (JSC) of ~4.22 mA cm−2 with an open circuit voltage (VOC) of 0.615 V and a fill factor (FF) of ~0.54. ZnO nanostructures...
We have grown Zinc Oxide (ZnO) nanosheet layers on bare glass and conducting Fluorine doped tin oxide (FTO) glass substrates by hydrothermal route. Aluminum doped ZnO (AZO) layer was deposited using a spin coating method prior to growth of ZnO nanostructures which is then used as a seed layer in hydrothermal growth. Asgrown zinc oxide films' structure, surface morphology and optical properties were studied by using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Ultraviolet Visible (UV-Vis) Spectrophotometer, respectively. XRD study confirmed hexagonal wurtzite structure of ZnO orienting along (002) planes. Scanning Electron Microscope image clearly shows the growth of nanosheet like structures of ZnO.
2018
ZnO nanoparticles (ZnO NPs) were synthesized using hydrothermal and sol-gel techniques using zinc acetate dihydrate (Zn (CH3COO)2.2H2O) as a row material and methanol as a solvent. The structural properties of ZnO NPs were studied using EDX, XRD, TEM, and the optical properties were characterized using UV-VIS and PL spectroscopies. The synthesized ZnO NPs showed high purity and revealed a wurtzite (hexagonal) crystal structure with particle size (D) ranged from 25 nm to 28 nm. The UV-VIS absorption spectra of ZnO NPs samples and sensitizing dyes were performed. The obtained ZnO NPs exhibited the direct optical bandgap 3.15 eV. Dye-sensitized solar cells (DSSCs) were fabricated using synthesized ZnO NPs as a semiconducting layer, which was dyed with different low cost dyes such as Eosin B (EB), Eosin Y (EY) and Rhodamine B (RB) that was used to sensitize the photoanode (ZnO NPs). The experimental results showed a significant efficiency for the fabricated DSSCs of synthesized ZnO NPs ...
Zinc oxide nanostructure-based dye-sensitized solar cells
Journal of Materials Science, 2017
Developing new technologies that could lead to alternatives to the traditional silicon-based solar panels, and to efficiently light the world in the future, is critically important because of limited natural petroleum resources. Dye-sensitized solar cells (DSSCs) are promisingly efficient and clean hybrid, organicinorganic, low-cost molecular solar cell devices. The key components of DSSCs are the organic dyes that play the role of a photosensitizer-like the chlorophyll of a green plant that is responsible for photosynthesis-and nanostructured semiconductor metal oxides. Because of their unique, multifunctional properties, zinc oxide (ZnO) nanostructures are promising materials to use to create photoanodes for DSSCs. This review looks at recent developments in the field of ZnO-based DSSC devices; synthesis of ZnO nanostructures with variable morphologies, including nanorods, nanofibers, nanotubes, nano-/microflowers, thin sheets, and nanoaggregates; factors that control the growth and morphologies of these nanomaterials; and the role of crystallographic planes for the synthesis of versatile ZnO nanostructures. This review also covers photoelectrode fabrication, DSSC device components, nature and chemical features of the dyes used as photosensitizers, and operational principles. In addition, various photovoltaic parameters such as current density, open-circuit voltage, fill factor, photoconversion efficiency, and factors that influence these parameters for ZnO-based DSSCs are summarized and discussed.
We have grown Zinc Oxide (ZnO) nanosheet layers on bare glass and conducting Fluorine doped tin oxide (FTO) glass substrates by hydrothermal route. Aluminum doped ZnO (AZO) layer was deposited using a spin coating method prior to growth of ZnO nanostructures which is then used as a seed layer in hydrothermal growth. Asgrown zinc oxide films' structure, surface morphology and optical properties were studied by using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Ultraviolet Visible (UV-Vis) Spectrophotometer, respectively. XRD study confirmed hexagonal wurtzite structure of ZnO orienting along (002) planes. Scanning Electron Microscope image clearly shows the growth of nanosheet like structures of ZnO.
Zinc oxide (ZnO) is a unique semiconductor material that exhibits numerous useful properties for dye-sensitized solar cells (DSSCs) and other applications. Various thin-film growth techniques have been used to produce nanowires, nanorods, nanotubes, nanotips, nanosheets, nanobelts and terapods of ZnO. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in solar cells, optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by various techniques and their application in DSSCs. The application of ZnO nanowires, nanorods in DSSCs became outstanding, providing a direct pathway to the anode for photo-generated electrons thereby suppressing carrier recombination. This is a novel characteristic which increases the efficiency of ZnO based dye-sensitized solar cells.
ZnO Nanorods Formation for Dye-Sensitized Solar Cells Applications
International Journal of Technology, 2017
Different morphologies of zinc oxide (ZnO) can be obtained through various synthesizing methods, such as that of the water bath. By synthesizing under various conditions, different ZnO morphologies can be seen as the result of the water bath method. Replacing ZnO nanoparticles with vertically aligned ZnO nanorods results in a much higher energy conversion efficiency. Yet vertically aligned nanorods can only be grown through difficult and expensive methods. Several researchers have studied the growth of one-dimensional (1D) nanorods on homogeneous film with various growth conditions. However, there has been little in the way of research on ZnO nanorods grown on ZnO seed layers using the water bath method. In this research, vertically aligned nanorods with an optimum size ratio were formed through a simple water bath method. This method reveals that the ZnO nanorods are well aligned and grown with a high density and uniformity on the substrate. Their X-ray diffraction patterns reveal that the nanorods are grow in the [001] direction. The density, diameter, and length of the ZnO nanorods can be altered by changing the growing condition. All of the samples were characterized using a scanning electron microscope, X-ray diffraction, and micro Raman spectroscopy. To investigate crystal growth, zinc nitrate and zinc acetate were used when preparing the solution. The results demonstrate that the morphology and alignment of ZnO nanorods are determined by the precursor's type and deposition time.