ZnO nanorods on undoped and indium-doped ZnO thin films as a TCO layer on nonconductive glass for dye-sensitized solar cells (original) (raw)
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International Journal of Photoenergy, 2010
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Oriental Journal of Chemistry, 2018
In this work, the effect of indium (In) and gallium (Ga) dopants on the structural, optical and electrical properties of ZnO thin films was studied. ZnO thin films were deposited on glass substrates at 400°C using the spray pyrolysis deposition technique. X-ray diffraction (XRD) results indicated that both undoped and doped ZnO films had (002) preferred orientation. The undoped ZnO films were found to exhibit high transmittance above 80%, while indium-doped (In:ZnO) and galliumdoped (Ga:ZnO) films had transmittance above 60% and 70% respectively. From the Hall Effect measurements, doping improved the conductivity of the ZnO thin films however, In:ZnO films showed higher electrical conductivity compared to Ga:ZnO films. Electron probe microanalysis (EPMA) results were used to confirm the presence of the respective dopants in the thin film samples.
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Nanoscale Research Letters, 2012
Aligned ZnO nanowires with different lengths (1 to approximately 4 μm) have been deposited on indium titanium oxide-coated glass substrates by using the solution phase deposition method for application as a work electrode in dye-sensitized solar cells (DSSC). From the results, the increases in length of zinc oxide (ZnO) nanowires can increase adsorption of the N3 dye through ZnO nanowires to improve the short-circuit photocurrent (J sc) and open-circuit voltage (V oc), respectively. However, the J sc and V oc values of DSSC with ZnO nanowires length of 4.0 μm (4.8 mA/cm 2 and 0.58 V) are smaller than those of DSSC with ZnO nanowires length of 3.0 μm (5.6 mA/cm 2 and 0.62 V). It could be due to the increased length of ZnO nanowires also resulted in a decrease in the transmittance of ZnO nanowires thus reducing the incident light intensity on the N3 dye. Optimum power conversion efficiency (η) of 1.49% was obtained in a DSSC with the ZnO nanowires length of 3 μm.
Effect of a compact ZnO interlayer on the performance of ZnO-based dye-sensitized solar cells
Solar Energy Materials and Solar Cells
ZnO is a promising material for application in dye-sensitized solar cells, related to its attractive electrical properties and the facile preparation of nanomaterials, with excellent control over the structure and morphology. In this work ZnO-based dye-sensitized solar cells were prepared, and the effect of the presence of a compact ZnO interlayer between the transparent conducting oxide (TCO) electrode and the nanostructured, mesoporous ZnO film on the performance of the solar cell is reported. The compact interlayer was deposited using planar rf magnetron sputtering, and the ZnO nanomaterial was prepared by forced hydrolysis from zinc acetate in ethanol solution. The presence of the compact interlayer has a positive effect on the overall characteristics of the solar cell and decreases the recombination rate from the TCO substrate, resulting in a higher open circuit voltage under low light conditions. The best efficiency of non-optimized solar cells at 1 sun was 4.0%.
Indium-doped ZnO thin films deposited by the sol–gel technique
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Conducting and transparent indium-doped ZnO thin films were deposited on sodocalcic glass substrates by the sol-gel technique. Zinc acetate and indium chloride were used as precursor materials. The electrical resistivity, structure, morphology and optical transmittance of the films were analyzed as a function of the film thickness and the post-deposition annealing treatments in vacuum, oxygen or argon. The obtained films exhibited a (002) preferential growth in all the cases. Surface morphology studies showed that an increase in the films' thickness causes an increase in the grain size. Films with 0.18 Am thickness, prepared under optimal deposition conditions followed by an annealing treatment in vacuum showed electrical resistivity of 1.3 Â 10 À 2 Vcm and optical transmittance higher than 85%. These results make ZnO:In thin films an attractive material for transparent electrodes in thin film solar cells.
Effects of Na-doping on the efficiency of ZnO nanorods-based dye sensitized solar cells
Journal of Materials Science: Materials in Electronics, 2014
Na-doped ZnO nanorods (Zn 1-x Na x O: x = 0.0, 0.02, 0.04) were grown by a chemical bath deposition method on ZnO seeded FTO substrates. The influence of Na-doping on the efficiency of ZnO nanorods-based dye-sensitized solar cells (DSSCs) was investigated. Undoped and Na-doped ZnO nanorods were used as photo-anodes for the fabricated DSSCs. X-ray diffraction measurements exhibited that all the samples had a wurtzite structure of ZnO with a preferred orientation of (002) plane. Scanning electron microscopy images of the samples revealed that all the samples displayed hexagonal shaped nanorods. It was observed from optical measurements that the band gap energy gradually decreased from 3.29 to 3.21 eV for undoped and 4 at.% Na-doped ZnO nanorods, respectively. Photoluminescence spectrum for undoped ZnO showed three peaks located at 379, 422, and 585 nm corresponding to UV emission, zinc vacancy, and deep level emission (DLE) peaks, respectively. When ZnO nanorods were doped with 2 at.% Na, the intensity of UV peak increased whereas the intensity of DLE peak decreased. The maximum conversion efficiency of DSSCs was found to be 0.22 % with a J sc of 0.80 mA/cm 2 , V oc of 0.49 V, and fill factor of 0.523 as ZnO nanorods were doped with 2 at.% Na atoms.
2018
In the present work, Ga-doped ZnO (GZO) thin films and ZnO nanorods (ZNRs) were fabricated for possible use as a transparent conducting oxide (TCO) film and a semiconductor oxide (SC) material, respectively, for photoelectrode component of the dye-sensitized solar cells (DSSCs). The GZO nanoparticles (NPs) were synthesized using the reflux-precipitation method, while ZNRs were grown on glass substrates seeded with an optimized GZO layer by the chemical bath deposition (CBD) method. The material properties of the samples were studied using various techniques. The X-ray diffraction patterns for all the GZO NPs and ZNRs exhibited a highly crystalline and hexagonal wurtzite structure of ZnO with no impurity phases. The values of the crystallite sizes range from 11 - 28 and 21 - 31 nm for the NPs and ZNRs samples, respectively. Peak shifts to lower diffraction angles from 47.45 - 47.35° with the increase in Ga/Zn solution pH was observed. A similar trend was observed also for other growt...
Micromachines
This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64 mA/cm2 and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency of the NWs+a single layer of NPs was found to be 2.28%, with a short-circuit photocurrent density (JSC) of 3.02 mA/cm2, open-circuit voltage (VOC) of 0.74 V, and a fill factor (FF) of 0.76, which is 60% higher than that of NWs cells and over 165% higher than NWs+a triple layer of NPs-based DSSCs....
Materials Letters, 2015
The synthesis of ZnO nanorods on transparent conducting oxides, Al doped ZnO seed layer on glass substrate (AZO) and indium tin oxide substrate (ITO) by using zinc nitrate hexahydrate (Zn (NO 3) 2 •6H 2 O) and Hexamethylenetetramine (HMT, (CH 2)6N 4 as raw materials is presented. The ZnO seed layer was fabricated by depositing an Al-doped ZnO thin film on glass substrate by sputtering. The effect of seeding on (AZO) and (ITO) substrate by using the wet chemical route growth of ZnO nanorods was investigated. The synthesized nanostructures of ZnO were characterized by X-ray diffraction (XRD), UV-Vis absorption spectroscopy, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results indicated that all the nanostructures of ZnO were preferentially grown as nanorods along [0002] direction (c-axis) of the hexagonal wurtzite structure and the nanorods which were grown on annealed seeded substrate are well shaped hexagonal faceted than those formed on non seeded substrate. However we have observed that when we were increasing the aluminum doping on the seed layer the ZnO growth was as nanoplatelets.