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1.
A ZnO nanorods (NRs)/TiO 2 nanoparticles (NPs) film has been prepared by electrochemical deposition of ZnO NRs growth on P25 TiO 2 NPs film surfaces. It was found that ZnO NRs/TiO 2 NPs could significantly improve the efficiency of dye-sensitized solar cells owing to its relatively enhanced light-scattering capability and efficient charge transport efficiency. The overall energy-conversion efficiency ( η) of 3.48 % was achieved by the formation of ZnO NRs/TiO 2 NPs film, which is 33 % higher than that formed by TiO 2 NPs alone ( η = 2.62 %). The charge recombination behavior of cells was investigated by electrochemical impedance spectra, and the results showed that ZnO NRs/TiO 2 NPs film has the longer electron lifetime than TiO 2 NPs alone, which could facilitate the reduction of recombination processes and thus would promote the photocatalysis and solar cell performance. 相似文献
2.
The effects of the nitric acid (HNO 3) treatment of TiO 2 nanoparticles on the photovoltaic properties of the dye-sensitized solar cell (DSSC) were investigated. The HNO 3 treatment enhanced the dispersion of TiO 2 particles, increased the surface area and porosity of the sintered TiO 2 films, increased the relative proportion of the Ti 3+ state in the Ti 2p X-ray photoelectron spectroscopy spectrum, significantly increased the amount of adsorbed dye molecules on the TiO 2 electrode, and reduced the charge-transfer resistance at the TiO 2/dye/electrolyte interface. The short circuit photocurrent density ( Isc) was increased due to the increased amount of adsorbed dye molecules and the reduced charge-transfer resistance. The HNO 3 pre-treatment of TiO 2 particles improved the overall conversion efficiency of the DSSC by about 14%. 相似文献
3.
Nanocrystalline anatase TiO 2 thin films with different thicknesses (0.5-2.0 μm) have been deposited on ITO-coated glass substrates by a sol-gel method and rapid thermal annealing for application as the work electrode for dye-sensitized solar cells (DSSC). From the results, the increases in thickness of TiO 2 films can increase adsorption of the N3 dye through TiO 2 layers to improve the short-circuit photocurrent ( Jsc) and open-circuit voltage ( Voc), respectively. However, the Jsc and Voc of DSSC with a TiO 2 film thickness of 2.0 μm (8.5 mA/cm 2 and 0.61 V) are smaller than those of DSSC with a TiO 2 film thickness of 1.5 μm (9.2 mA/cm 2 and 0.62 V). It could be due to the fact that the increased thickness of TiO 2 thin films also resulted in a decrease in the transmittance of TiO 2 thin films thus reducing the incident light intensity on the N3 dye. An optimum power conversion efficiency ( η) of 2.9% was obtained in a DSSC with the TiO 2 film thickness of 1.5 μm. 相似文献
4.
Highly branched, jacks-like ZnO nanorods architecture were explored as a photoanode in dye-sensitized solar cells, and their photovoltaic performance was compared with that of branch-free ZnO nanorods photoanodes. The highly branched network and large pores of the jacks-like ZnO nanorods electrodes enhances the charge transport, and electrolyte penetration. Thus, the jacks-like ZnO nanorods DSSCs render a higher conversion efficiency of η = 1.82% ( Voc = 0.59 V, Jsc = 5.52 mA cm −2) than that of the branch-free ZnO nanorods electrodes ( η = 1.08%, Voc = 0.49 V, Jsc = 4.02 mA cm −2). The incident photon-to-current conversion efficiency measurements reveal that the jacks-like ZnO nanorods DSSCs exhibit higher internal quantum efficiency (∼59.1%) than do the branch-free ZnO nanorods DSSC (∼52.5%). The charge transfer resistances at the ZnO/dye/electrolyte interfaces investigated using electrochemical impedance spectroscopy showed that the jacks-like ZnO nanorods DSSC had high charge transfer resistance and a slightly longer electron lifetime, thus improving the solar-cell performance. 相似文献
5.
Three-dimensional nanoparticles-based ZnO hierarchical spheres (ZnO-HS) with strong light harvesting and dye loading abilities have been fabricated by a simple hydrothermal method in this paper. These ZnO-HS were designed as the overlayer for light blocking and applied to the dye-sensitized solar cells (DSSCs) based on bare ZnO nanoparticles (ZnO-NP) or TiO 2 nanoparticles (TiO 2-NP). The results show that the values of the short-circuit current density ( J sc) and the power conversion efficiency ( η) have been heightened up to 12.6 mA cm ?2 and 3.40 % for the ZnO-NP/ZnO-HS double-layered DSSC, far higher than the bare ZnO-NP DSSC. However, another DSSC assembled by the TiO 2-NP/ZnO-HS double-layered film displays an adverse result for the decreasing of J sc and η even though the ZnO-HS light blocking layer has been established on the TiO 2-NP film. According to the electrochemical impedance data compared between the ZnO-NP/ZnO-HS double-layered and TiO 2-NP/ZnO-HS double-layered DSSC, it is found that the former possesses less possibility for the occurrence of charge recombination and electronic loss, which is responsible for its better photovoltaic response. 相似文献
6.
Ultrapure TiO 2 nanoparticles (∼5 nm in size) were supported on “inert” BaTiO 3 films by TiCl 4 treatment, which was used to fabricate dye-sensitized solar cells (DSSCs). The optimized electrode, designated as BaTiO 3/TiO 2(4), was obtained upon four cycles of TiCl 4 treatment. DSSC with BaTiO 3/TiO 2(4) electrode exhibits superior power conversion efficiency (PCE) compared to that with conventional anatase TiO 2 (∼25 nm in size) electrode. The interfacial charge recombination kinetics was investigated by electrochemical impedance spectroscopy (EIS) and intensity-modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS). In contrast to DSSC with anatase TiO 2 electrode, the dramatically enhanced electron lifetime for DSSC with BaTiO 3/TiO 2(4) electrode could be attributed to the decrease of recombination reaction at the TiO 2 photoelectrode/electrolyte interface. It is proposed that the lower interfacial charge recombination can be related to the relatively shallower trap distributions in DSSC with BaTiO 3/TiO 2(4) electrode. 相似文献
7.
TiO 2 nanoparticles were synthesized by hydrothermal process to prepare metal oxide based photoanode for dye sensitized solar cell (DSSC) fabrication. X-ray diffraction analysis indicates the formation of tetragonal TiO 2. High resolution transmission electron microscopy reveals the presence of agglomerated TiO 2 particles and the average particle size is found to be 14 nm. The UV–Visible absorption spectrum ensures the absorption maximum at 268 nm. The band gap energy of TiO 2 nanoparticles was found to be 3.3 eV which lies in the ultra-violet (UV) region. Impedance studies of TiO 2 nanoparticles show an increase in conductivity with an increase in bias voltage. In the present work, the UV active TiO 2 nanoparticles are employed for the fabrication of DSSC based on the hybrid co-sensitization of natural dye (Eugenia Jambolana) and organic dye (Eosin). The interfacial charge transfer resistance phenomena of the DSSC determined by electrochemical impedance spectroscopy is discussed in detail. Photovoltaic efficiency of 0.1377 % is achieved for the fabricated DSSC with co-sensitization of natural and organic dyes. 相似文献
8.
The present paper attempts to report the preparation of TiO 2–ZnO nanocomposite photoanode materials for dye-sensitized solar cells (DSSC) and analyse the efficiency of DSSC with natural dyes. The structural and optical characteristics of the composites were studied by transmission electron microscopy, X-ray diffraction, field effective scanning electron microscopy, energy dispersive spectrometry, photoluminescence and absorption spectroscopy. The synthesized nanocomposites formed on FTO substrates are applied as photoanode in a dye-sensitized solar cell (DSC). The natural dyes extracted from Beta vulgaris (Beetroot) and Syzygium cumini (black plum) were used in the fabrication of DSSC. The solar cells’ photovoltaic performance in terms of short-circuit current, open circuit voltage, fill factor and energy conversion efficiency was tested with photocurrent density–voltage measurements. The evolution of the solar cells parameters is explored as a function of the photoanode and type of dye used in DSSC fabrication.The obtained results show that the efficiency of DSSC significantly changes with the addition of ZnO to TiO 2, while the Beta vulgaris dye has evidently shown higher photo sensitized performance compared to Syzygium cumini in the preparation of DSSC. 相似文献
9.
This paper outlines a new strategy to optimize the performance of electrodes in dye-sensitized solar cells (DSSCs), through the engineering of electronic structures in conjunction with the micro-structures of the devices. We propose a simple hydrolysis method for the fabrication of a family of quasi-core–shell TiO 2 (hydrolysis)/PbS composites for working electrodes. Measurements confirm a shift in absorption from the UV to visible range. We also measured cell performance, including short-circuit photocurrent, open-circuit photovoltage, and the power conversion efficiency ( η) of DSSCs. The obtained η of DSSC (6.05%) with a TiO 2 (P-25)/TiO 2 (hydrolysis) + 0.005 M PbS electrode is substantially higher than that of the conventional DSSC (5.11%) with a TiO 2 (P-25) electrode, due to improved p–n junctions, light-scattering, and light absorption. Finally, the shell of TiO 2 (hydrolysis) protected the core of PbS from the corrosive effects of electrolytes, thereby prolonging the life span of the DSSC. This novel approach to electrode design could lead to advances in DSSC as well as other energy applications including photo-catalysis technology. 相似文献
10.
Pure and Copper/Nitrogen (Cu/N)-codoped TiO 2 photoanodes with various Cu concentrations are prepared via sol–gel route for the photoanode application in dye-sensitized solar cells (DSSCs). All the prepared samples are characterized by X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), UV–Vis spectroscopy (UV–VIS) and Electrochemical Impedance Spectroscopy (EIS). Addition of suitable amount of Cu and N content in TiO 2 can alter its optical and electrical properties by extending absorption in the visible region and band gap reduction. The results show that some of the Ti sites are replaced by Cu atoms while O sites are occupied by N atoms. Upon adequate addition of Cu/N could lead to smaller particle size, higher specific surface area, increased dye adsorption and retarded charge carrier recombination. A significant improvement in the power conversion efficiency is observed in case of optimized 0.3 mol% Cu/N-doped TiO 2 nanoparticles (NPs) based DSSC. This optimized 0.3 mol% Cu/N-doped photoanode accomplished a best power conversion efficiency of 11.70% with a short circuit current density of 23.41 mA cm ?2 which is 41% higher than that of the pure TiO 2 photoanode based DSSC (6.82%). 相似文献
11.
A meso-macroporous TiO 2 film electrode was fabricated by using mesoporous TiO 2 (m-TiO 2) nanoparticles through a screen-printing technique in order to efficiently control the main fabrication step of dye-sensitized solar cells (DSSCs). The qualities of the screen-printed m-TiO 2 films were characterized by means of spectroscopy, electron microscopy, nitrogen adsorption–desorption and photoelectrochemical measurements. Under the optimal paste composition and printing conditions, the DSSC based on the meso-macroporous m-TiO 2 film electrode exhibits an energy conversion efficiency of 4.14%, which is improved by 1.70% in comparison with DSSC made with commercially available nonporous TiO 2 nanoparticles (P25, Degussa) electrode printed with a similar paste composition. The meso-macroporous structure within the m-TiO 2 film is of great benefit to the dye adsorption, light absorption and the electrolyte transportation, and then to the improvement of the overall energy conversion efficiency of DSSC. 相似文献
12.
Low-cost quasi-solid-state dye-sensitized solar cells (DSSCs) are designed and fabricated by using a metal-free organic dye
and a mesoporous carbon aerogel instead of expensive ruthenium-based sensitizers and Pt electrode. The electrospun TiO 2 nanorods are added into a polyvinylidene fluoride (PVDF) solution to form a 3D network nanocomposite gel electrolyte. The
presence of TiO 2 nanorods in the gel electrolyte obviously increases the ionic conductivity and decreases charge-transfer resistance of the
DSSC. The effects of the gel electrolyte and the carbon aerogel counter electrode on electrochemical and photovoltaic properties
have been investigated in detail. Particularly, an optimized DSSC with a nanocomposite gel electrolyte and a carbon aerogel
counter electrode affords a power conversion efficiency (PCE) of 6.20% at a light intensity of 100 mW cm −2. 相似文献
13.
Alkyl and fluoroalkyl substituted symmetrical and unsymmetrical squaraine dyes have been synthesized for the fabrication of dye-sensitized solar cells (DSSC) based on nanoporous TiO 2. Results of DSSC performance clearly indicate that introduction of molecular asymmetry and increase in the alkyl chain length of the squaraine sensitizers leads to the enhancement in the photovoltaic performance. A perusal of photo-action spectra of squaraine sensitizer corroborates that introduction of molecular asymmetry and fluoroalkyl substitution leads to hampering of blue-shifted H-aggregate formation. Estimation of energy of HOMO and LUMO for these squaraine sensitizers used in the present investigation indicates that about 0.16 eV is sufficient for electron injection from photoexcited dye to TiO 2 conduction band and dye regeneration. 相似文献
14.
Nanomaterials play important role in performance of dye-sensitized solar cells. In this paper, highly phase pure anatase TiO2 microspheres were synthesized using a low-cost hydrothermal route. Initially, X-ray diffraction studies and Raman spectroscopic analysis were carried out, and the formation of tetragonal structure of TiO2 with the anatase phase was confirmed. The UV–Vis DRS studies showed the excellent reflectance and optical band-gap energy of 3.29 eV. The well-interconnected spherical nanoparticles with different sizes were examined by Field Emission Scanning Electron Microscopic analysis. The fabricated dye-sensitized solar cell (DSSC) composed of prepared TiO2 microspheres as photoanode exhibited a higher power conversion efficiency (PCE) (η) of 5.4% as compared to commercial P25 with PCE of 3.6%. The higher Jsc (12.03 mA/cm2) in the fabricated DSSC due to efficient dye loading capacity and high light-scattering property was also observed. 相似文献
15.
Cluster like mesoporous TiO 2 spheres, nanorods and nanoparticles were synthesized by simple wet chemical method. The TiO 2 mesoporous spheres, nanorods and nanoparticles were characterized by powder X-ray diffraction, Raman spectroscopy, ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. Accordingly, a possible growth mechanism of mesoporous spheres, nanorods and nanoparticles were discussed. The changes of the dye-sensitized solar cell (DSSC) performance with the variation of the nanostructures of TiO 2 which were used in photoanodes have been investigated. The TiO 2 mesoporous sphere based DSSC with the film thickness of 20 μm was assembled and a conversion efficiency of 6.69% was obtained. 相似文献
16.
The objective of this work was to investigate the improvement in performance of dye sensitized solar cells (DSSCs) by depositing ultra thin metal oxides (hafnium oxide (HfO 2) and aluminum oxide (Al 2O 3)) on mesoporous TiO 2 photoelectrode using atomic layer deposition (ALD) method. Different thicknesses of HfO 2 and Al 2O 3 layers (5, 10 and 20 ALD cycles) were deposited on the mesoporous TiO 2 surface prior to dye loading process used for fabrication of DSSCs. It was observed that the ALD deposition of ultrathin oxides significantly improved the performance of DSSCs and that the improvement in the DSSC performance depends on the thickness of the deposited HfO 2 and Al 2O 3 films. Compared to a reference DSSC the incorporation of a HfO 2 layer resulted in 69% improvement (from 4.2 to 7.1%) in the efficiency of the cell and incorporation of Al 2O 3 (20 cycles) resulted in 19% improvement (from 4.2 to 5.0%) in the efficiency of the cell. These results suggest that ultrathin metal oxide layers affect the density and the distribution of interface states at the TiO 2/organic dye and TiO 2/liquid electrolyte interfaces and hence can be utilized to treat these interfaces in DSSCs. 相似文献
17.
In contrast to the conventional DSSC systems, where the dye molecules are used as light harvesting material, here a solid-state absorber was used as a sensitizer in conjunction with the dye. The materials like ZnO and Al 2O 3 : C, which will show optically stimulated luminescence (OSL) upon irradiation were used as extremely thin absorber layers. This novel architecture allows broader spectral absorption, an increase in photocurrent, and hence, an improved efficiency because of the mobility of the trapped electrons in the absorber material after irradiation, to the TiO 2 conduction band. Nanocrystalline mesoporous TiO 2 photoanodes were fabricated using these solid-state absorber materials and after irradiation, a few number of samples were co-sensitized with N719 dye. On comparing both the dye loaded photoanodes (ZnO/TiO 2 and Al 2O 3 : C/TiO 2), it can be concluded from the present studies that, the Al 2O 3 : C is superior to ZnO under photon irradiation. Al 2O 3 : C is more sensitive to photon irradiation than ZnO and hence there can be more trap centres produced in Al 2O 3 : C. 相似文献
18.
This study examined the characterization of nanoporous structured titanium dioxide and its application to dye-sensitized solar cells (DSSCs). TEM revealed nanopore sizes of 10.0 nm with a regular hexagonal form. When nanoporous structured TiO 2 was applied to DSSC, the energy conversion efficiency was enhanced considerably compared with that using nanometer sized TiO 2 prepared using a hydrothermal method. The energy conversion efficiency of the DSSC prepared from nanoporous structured TiO 2 was approximately 8.71% with the N719 dye under 100 mW cm −2 simulated light. FT-IR spectroscopy showed that the dye molecules were attached perfectly to the surface and more dye molecules were absorbed on the nanoporous structured TiO 2 than on the nano-sized TiO 2 particles prepared using a conventional hydrothermal method. Electrostatic force microscopy (EFM) showed that the electrons were transferred rapidly to the surface of the nanoporous structured TiO 2 film. 相似文献
19.
A series of composite films based on LiFePO 4/TiO 2/Pt were synthesized and used as counter electrodes for dye sensitized solar cells (DSSCs). The composites are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET). These analysis results demonstrate that the crystal structure of LiFePO 4 in composite is not changed, and the prepared LiFePO 4/TiO 2/Pt composite films hold a rough surface and porous structure which provide more catalytic activity sites for I 3 ? reduction and more space for I ?/I 3 ? diffusion. The DSSC based on LiFePO 4/TiO 2/Pt composite CEs shows a high power conversion efficiency of 6.23% at a low Pt dosage of 2%, comparable to the conventional magnetron sputtering Pt CE (6.31%). The electrochemical analysis reveals that the presented composite CEs have good electrocatalytic activity and low charge transfer resistance. Furthermore, the DSSCs based on LiFePO 4/TiO 2/Pt composite CE exhibit high stability under the continuous tests condition and electrolyte soaking. The results suggest that this LiFePO 4-based composite film could be a perspective electrode for practical application of DSSCs and it maybe provide a potential for further research about photo-charging lithium-ion batteries. 相似文献
20.
A novel TiO 2 nanotube array/CdS nanoparticle/ZnO nanorod (TiO 2 NT/CdS/ZnO NR) photocatalyst was constructed by chemical assembling CdS into the TiO 2 NTs, and then laying ZnO NRs on the surface. The SEM results showed that the TiO 2 NTs looked like many “nano test tubes” and the ZnO NRs served as the corks to seal the nozzle. This photocatalyst exhibited a wide absorption range (200-535 nm) in both ultraviolet and visible regions (UV-vis region), and maintained very high photoelectrocatalytic (PEC) activities. The maximum photoelectric conversion efficiencies ( η) of TiO 2 NT/CdS/ZnO NRs are 31.8 and 5.98% under UV light (365 nm) and visible light (420-800 nm), respectively. 相似文献
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