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1.
Ordered nanoporous TiO 2 materials (MK-TiO 2, MS-TiO 2, and MU-TiO 2) were synthesized for the dye-sensitized solar cell (DSSC) by using different silica templates such as KIT-6, SBA-15, and MSU-H. To prepare a photoelectrode in DSSC, cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)-ruthenium(II)bis-tetrabutylammonium dye (N719) was adsorbed onto the synthesized nanoporous TiO 2 materials. The samples were characterized by XRD, TEM, FE-SEM, AFM, and N 2 adsorption analyses. The photovoltaic performance of DSSC was evaluated from the overall conversion efficiency, fill factor, open-circuit voltage, and short-circuit current from the I- V curves measured. It was found that the photoelectric performance is highly dependent on the adsorption properties of N719 dye molecules on the nanoporous TiO 2 replicas (MK-TiO 2, MS-TiO 2, and MU-TiO 2) synthesized from different silica templates. 相似文献
2.
The solar cell performance of the black dye, N719 dye and the cocktail of two dyes on TiO 2 films were studied by mean of the utilization as light harvesting electrodes in solid-state FTO|TiO 2|dye|CuI|Cr–FTO cells. The power conversion efficiencies of 3.8% and 3.0% are obtained when N719 and black dye were used. When the mixture of 1:1 of two dyes was used, the conversion efficiency rises to 4.6%. In the mixture of N719 and black dye, the N719 dye acts as the aggregation preventer and a co-absorber on TiO 2 surfaces. The increased absorption of light by the two dyes results in increase of electron injection thus enhancing both the short-circuit current density and the open circuit voltage contributing to increased power conversion efficiency of the cell. 相似文献
3.
Hydrothermal process has been employed to synthesize titanium oxide (TiO 2) bottle brush. The nanostructured bottle brushes with tetragonal nanorods of ~75 nm diameter have been synthesized by changing the nature of the precursors and hydrothermal processing parameters. The morphological features and structural properties of TiO 2 films were investigated by field emission scanning electron microscopy, X-ray diffraction, high-resolution transmission electron spectroscopy, Fourier transform Raman spectroscopy, and X-ray photoelectron spectroscopy. The influence of such nanostructures on the performance of dye-sensitized solar cells (DSSCs) is investigated in detail. The interface and transient properties of these nanorods and bottle brush-based photoanodes in DSSCs were analyzed by electrochemical impedance spectroscopic measurements in order to understand the critical factors contributing to such high power conversion efficiency. Surface area of sample was recorded using Brunauer–Emmett–Teller measurements. It is found that bottle brush provides effective large surface area 89.34 m 2 g ?1 which is much higher than TiO 2 nanorods 63.7 m 2 g ?1. Such effective surface area can facilitate the effective light harvesting, and hence improves the dye adsorption and the photovoltaic performance of DSSCs, typically in short-circuit photocurrent and power conversion efficiency. A best power conversion efficiency of 6.63 % has been achieved. We believe that the present device performance would have wide interests in dye-sensitized solar cell research. 相似文献
4.
Dye-sensitized solar cells (DSSCs) were fabricated using TiO 2 nanoparticles (NPs), TiO 2 nanotube arrays (NTAs), and surface-modified NTAs with a TiCl 4 treatment. The photovoltaic efficiencies of the DSSCs using TiO 2 NP, NTA, and TiCl 4-treated NTA electrodes are 4.25, 4.74, and 7.47 %, respectively. The highest performance was observed with a TiCl 4-treated TiO 2 NTA photoanode, although in the case of the latter two electrodes, the amounts of N719 dye adsorbed were similar and 68 % of that of the NP electrode. Electrochemical impedance measurements show that the overall resistance, including the charge–transfer resistance, was smaller with NTA morphologies than with NP morphologies. We suggest that a different electron transfer mechanism along the one-dimensional nanostructure of the TiO 2 NTAs contributes to the smaller charge–transfer resistance, resulting in a higher short circuit current ( J sc), even at lower dye adsorption. Furthermore, the TiCl 4-treated NTAs showed even smaller charge–transfer resistance, resulting in the highest J sc value, because the downward shift in the conduction band edge improves the electron injection efficiency from the excited dye into the TiCl 4-treated TiO 2 electrodes. 相似文献
5.
CdS quantum dots (QDs) were introduced as an interface modifier in the poly(3-hexylthiophene) (P3HT)/TiO 2 nanorod arrays hybrid photovoltaic device. The presence of CdS QDs interlayer was found to provide enhanced light absorption, increased interfacial recombination resistance at the P3HT/TiO 2 interfaces, thus leading to a lower recombination rate of the electrons due to the stepwise structure of band edge in P3HT/CdS/TiO 2, which accounts for the observed enhanced photocurrent and photovoltage of the hybrid solar cells. The optimized performance was achieved in P3HT/CdS/TiO 2 hybrid solar cells after deposition of CdS QDs for 10 cycles, with a power conversion efficiency of 0.57 %, which is nearly ten times higher than that of P3HT/TiO 2. The findings indicate that inorganic semiconductor quantum dots provide effective means to improve the performance of polymer/TiO 2 hybrid solar cells. 相似文献
6.
Titania (TiO 2) nanorods have been synthesized with controlled size for dye-sensitized solar cells (DSSCs) via hydrothermal route at low hydrothermal temperature of 100 °C for 24 h. The titania nanorods were characterized using XRD, SEM, TEM/HRTEM, UV-vis Spectroscopy, FTIR and BET specific surface area ( S BET), as well as pore-size distribution by BJH. The results indicated that the bulk traps and the surface states within the TiO 2 nanorods films have enhanced the efficiency of DSSCs. The size of the titania nanorods was 6.7 nm in width and 22 nm in length. The high surface area can provide more sites for dye adsorption, while the fast photoelectron-transfer channel can enhance the photogenerated electron transfer to complete the circuit. The specific surface area S BET was 77.14 m 2?g ?1 at the synthesis conditions. However, the band gap energy of the obtained titania nanorods was 3.2 eV. The oriented nanorods with appropriate lengths are beneficial in improving the electron transport property and thus leading to the increase of photocurrent, together enhancing the power conversion efficiency. A nearly quantitative absorbed photon-to-electrical current conversion achieved upon excitation at wave length of 550 nm and the power efficiency was enhanced from 5.6 % for commercial TiO 2 nanoparticles Degussa (P25) cells to 7.2 % for TiO 2 nanorods cells under AM 1.5 illumination (100 mW?cm ?2). The TiO 2 cells performance was improved due to their high surface area, hierarchically mesoporous structures and fast electron-transfer rate compared with the Degussa (P25). 相似文献
7.
In the present paper, photovoltaic studies of dye-sensitized solar cells (DSSCs) based on betacyanin/TiO 2 and betacyanin/WO 3–TiO 2 have been done. The cell performances were compared through I– V curves and wavelength dependant photocurrent measurements for the two new types of DSSCs. The TiO 2-coated DSSC showed the photovoltage and photocurrent of 300 mV and 4.96 mA/cm 2, whereas the cell employing WO 3–TiO 2 photoelectrode showed the values 435 mV and 9.86 mA/cm 2, respectively. The conversion efficiency of TiO 2 based dye-sensitized solar cell was found to be 0.69 %, while WO 3–TiO 2-based cell exhibited a higher conversion efficiency of 2.2 %. The better performance of the WO 3–TiO 2 dye-sensitized solar cell photoelectrode is thought to be due to an inherent energy barrier at the electrode/electrolyte interface leading to the reduced recombination of photoinduced electrons. 相似文献
8.
Zinc oxide carbon nanotube (ZnO-CNTs) thin films were prepared by a chemical bath deposition (CBD) method and immersed in N719 dye for 24 h. The structure and surface morphology of the samples was captured by X-ray diffraction (XRD) and field effect scanning electron microscopy (FESEM) unit, respectively. The photovoltaic properties of ZnO- and ZnO-CNT-based dye-sensitized solar cells (DSSCs) were measured by considering the power conversion efficiency ( η), photocurrent density ( J sc), open-circuit voltage ( V oc), and fill factor (FF). The cell's efficiency doped with single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) reached 0.65 and 0.28 %, respectively. ZnO-based DSSC generated only η?=?0.003 %. The electrochemical impedance spectroscopy (EIS) unit was employed to investigate the electron transport properties such as effective electron lifetime ( τ eff), effective electron chemical diffusion coefficient ( D eff), and effective electron diffusion length ( L n ). The addition of CNTs has enhanced the photovoltaic properties of the DSSCs and reduced the recombination effect inside the solar cell. 相似文献
9.
TiO 2-reduced graphene oxide (RGO) composite was synthesized via a sol-gel process and investigated as an anode material for sodium-ion batteries (SIBs). A remarkable improvement in sodium ion storage with a reversible capacity of 227 mAh g ?1 after 50 cycles at 50 mA g ?1 is achieved, compared to that (33 mAh g ?1) for TiO 2. The enhanced electrochemical performance of TiO 2-RGO composite is attributed to the larger specific surface area and better electrical conductivity of TiO 2-RGO composite. The excellent performance of TiO 2-RGO composite enables it a potential electrode material for SIBs. 相似文献
10.
利用自制TiO 2纳米粒子研究敏化染敏太阳能电池. 使用自制的旋转涂布加热平台装置将产出的TiO 2粒子均匀的涂布在ITO导电玻璃上形成薄膜,浸泡于N-719 染料中12小时以上作为DSSCs的光电极
元件,最后完成染料敏化太阳能电池的系统组装并进行光电转换效率测量. 实验结果表明,放电过程产出的TiO 2纳米粒子具有锐钛矿晶相,粒径尺寸可控制在20~70 nm,粒子表面电位约为-30 mV,是稳定的纳米悬浮夜. 添加0.5 mL 的Triton X-100在导电玻璃表面上,利用的旋转涂布加热到22 oC可以制得厚度均匀缜密的薄膜结构,不但粒子不受到热处理效应与介面活性剂的影响而发生晶相改变,并且薄膜也有良好的染料吸附效果. 较厚二氧化钛薄膜的光电极会提升敏化染敏太阳能电池的效率. 实验结果得知,以15 μm的二氧化钛薄膜组装DSSCs测得最高效率2.15%,但是当薄膜厚度超过15 μm 则会导致开路电压与充填因子逐渐下降,光电转换效率变差. 相似文献
11.
A novel, facile, catalyst-free, and low temperature process for the synthesis of discrete anatase TiO2 nanocrystals has been developed in the absence of stabilizing agent. The product was shown to be discrete anatase TiO2 nanocrystals with a mean diameter of 4.97 ± 0.9 nm and a specific surface area of 393 m2/g. By varying the water content and precursor concentration, the particle size could be tuned. Also, the resultant colloid solution was quite stable even in the absence of stabilizing agent because of the coverage of EG molecules on the particle surface. In addition, the anatase TiO2 nanocrystals obtained in this work had highly thermal stability even at temperatures up to 800 °C. Also, as compared to Degussa P25 TiO2 powders, they exhibited stronger absorption at 200–350 nm and higher transmittance in the visible light region. Thus, the new approach proposed in this work was practicable for the synthesis of anatase TiO2 nanocrystals, particularly for those requested to have highly thermal stability and UVC-cut capability. 相似文献
12.
The TiO 2/BiOI heterostructured nanofibers were prepared by electrospinning–solvothermal two-step process. The BiOI nanosheets, which owned a thickness of tens of nanometers and an average side length of about 300 nm, were intensive and crossed arranging on the TiO 2 nanofibers whose diameter was about 400–550 nm and length was about 15–45 μm. The absorption edge of TiO 2/BiOI heterostructured nanofibers was extended to more than 600 nm in visible-light region and the TiO 2/BiOI exhibited enhanced visible-light photocatalytic performance and excellent recyclability compared to the individual TiO 2 nanofibers and the BiOI microflowers in the photodecomposition of methylene blue, which was ascribed to nanoscale size heterostructure, narrow energy band, peculiar band gap structures, and porous surface structure. 相似文献
13.
In this research, Cu-doped TiO 2 thin films have been successfully deposited onto a glass substrate by Sol–gel technique using dip coating method. The films were annealed at different annealing temperatures (400–500 °C) for 1 h. The structural, optical and electrical properties of the films were investigated and compared using X-ray Diffraction, UV–visible spectrophotometer and 4-point probe method. Optical analysis by mean transmittance T(λ) and absorption A(λ) measurements in the wavelength range between 300 to 800 nm allow us to determine the indirect band gap energy. DRX analysis of our thin films of TiO 2:Cu shows that the intensities of the line characteristic of anatase phase increasing in function of the temperature. 相似文献
14.
In this study, TiO 2 wedgy nanotubes with rectangular cross-sections were fabricated on transparent conductive substrates by using TiO 2 nanorods as the precursor via the anisotropic etching route. TiO2 nanotubes with V-shaped hollow structure and the special crystal plane exposed on the tube wall possess nature of high surface area for more dye molecules absorption, and the strong light scattering effects and dual-channel for effective electron transport of the TiO 2 V-shaped nanotubes based dye-sensitized solar cell exhibit a remarkable photovoltaic enhancement compared with the TiO 2 nanorods. The photoanode based on our V-shaped TiO 2 nanotubes with a length of 1.5 μm show a 123% increase of the dye loading and a 182% improvement in the overall conversion efficiency when compared with 4 μm rutile TiO 2 nanorods photoanode. 相似文献
15.
A ‘cap and dip’ method of adsorbing ruthenium di-2,2′-bipyridyl-4,4′-dicarboxylic acid diisocyanate (N3 dye) on a rutile TiO 2 (110) surface was investigated using pyrocatechol as a capping molecule. This method involves cleaning the rutile surface in ultra-high vacuum (UHV), depositing pyrocatechol onto the surface to ‘cap’ the adsorption sites, removing from vacuum, ‘dipping’ in an N3 dye solution and returning to vacuum. Photoemission measurements following the return of the crystal to vacuum suggest that the pyrocatechol keeps the surface free from contamination on exposure to atmosphere. Photoemission spectra also indicate that the pyrocatechol capping molecules are replaced by the N3 dye in solution and that the N3 dye is adsorbed intact on the rutile TiO 2 (110) surface. This technique may allow other large molecules, which are thermally unstable to evaporation in UHV, to be easily deposited onto TiO 2 surfaces. 相似文献
16.
The modification of non-metallic elements N and S to nanocrystalline TiO 2 anode results in the energy gap is reduced to 2.63 eV and a strong redshift to the visible region occurred in the UV–visible spectrum. Poly (3-decylthiophene) (P3DT) is synthesized. Ultraviolet–visible spectra (UV–vis) shows that the light absorption of P3DT (Poly (3-decylthiophene)) and N719 (RuL2(NCS)2:2TBA (L=2,2′-bipyridyl-4, 4′-dicarboxylic acid)) are complementary to cover the entire visible region. Solar cell based on N–S/TiO 2 is co-sensitized by P3DT and N719. The photoelectric conversion efficiency of co-sensitized solar cell increases 56.8% comparing with the single dye-sensitized solar cell. 相似文献
17.
The ZnO nanowire (NW) array/TiO 2 nanoparticle (NP) composite photoelectrode with controllable NW aspect ratio has been grown from aqueous solutions for the fabrication of dye-sensitized solar cells (DSSCs), which combines the advantages of the rapid electron transport in ZnO NW array and the high surface area of TiO 2 NPs. The results indicate that the composite photoelectrode achieves higher overall photoelectrical conversion efficiency ( η) than the ZnO NW alone. As a result, DSSCs based on the ZnO NW array/TiO 2 NP composite photoelectrodes get the enhanced photoelectrical conversion efficiency, and the highest η is also achieved by rational tuning the aspect ratio of ZnO NWs. With the proper aspect ratio (ca. 6) of ZnO NW, the ZnO NW array/TiO 2 NP composite DSSC exhibits the highest conversion efficiency (5.5 %). It is elucidated by the dye adsorption amount and interfacial electron transport of DSSCs with the ZnO NW array/TiO 2 NP composite photoelectrode, which is quantitatively characterized using the UV-Vis absorption spectra and electrochemical impedance spectra. It is evident that the DSSC with the proper aspect ratio of ZnO NW displays the high dye adsorption amount and fastest interfacial electron transfer. 相似文献
18.
The self-organized titania nanotube arrays (NTAs) fabricated by anodisation has gained enormous interest due to its high spatial orientation, excellent charge transfer structure, and large internal surface area; all are crucial properties influencing the absorption and propagation of light. In this study, a composite material, CdSe nanoparticle/TiO 2 nanotube arrays (CdSe/TiO 2 NTAs) were assembled through the insertion of CdSe nanoparticles onto the anodized TiO 2 nanotube arrays via electrochemical deposition. The annealing temperature of CdSe/TiO 2 NTAs was varied from 200 to 350 °C and was found to play an important role in controlling the formation of CdSe nanoparticles on TiO 2 NTAs. Characterizations of the films were performed by using field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, high resolution transmission electron microscopes, X-ray diffractometry and UV–visible diffuse reflectance spectroscopy. The transient photocurrent was examined in a three-electrode system under halogen illumination by using the prepared film as the photoanode. It was found that the CdSe nanoparticles were susceptible to spread through electrochemical deposition and formed on the nanotubes by annealing in nitrogen atmosphere. The increment in annealing temperature has resulted in greater amount of CdSe loaded onto TiO 2 nanotube arrays. Therefore, a suitable annealing temperature can enhance the particle interaction, leading to considerable improvement in PEC performance. The sensitized CdSe/TiO 2 NTAs annealed at 250 °C displayed 84 folds improvement in photoconversion efficiency than that of bare TiO 2 NTAs counterparts. 相似文献
19.
Li 2CO 3 modified carbon microbead composites (LCO/CMB-T) with different covering amount are prepared by solvent evaporation and dipping method. LiCH 3COO are first used as lithium source, which can provide a precise control of Li 2CO 3 amount through varying dipping times or solution concentration. The morphology, structure, and covering amount are characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), and atomic absorption spectrometer (AAS). The dipping process can produce the samples with better surface coverage, more uniform coating, and higher Li 2CO 3 crystallinity, while the appropriate amount of Li 2CO 3 can help to decrease initial irreversible capacity and improve cell performance. Here, the sample with 1.07 % Li 2CO 3 prepared by dipping method shows the highest initial discharge capacity of 353.7 mAh g ?1 and coulombic efficiency of 89.5 %. The capacity retention is up to 82.1 % after 30 cycles. 相似文献
20.
Self-cleaning and anti-bacterial activities of the photo-catalyst titanium dioxide make it a superior compound for use in the ceramics and glass industry. In order to achieve high self-cleaning efficiency for building products, it is important that Titania is present as anatase phase. Moreover, it is desirable that the particle sizes are in Nano-range, so that a large enough surface area is available for enhanced catalytic performance. In the present paper, Cobalt and Nickel co-doped (4%mol Ni and 4%mol Co doped TiO 2) and un-doped TiO 2 Nano powders have been prepared by sol–gel technique. They were calcined at the temperatures in the range of 475–1075 °C. Ni/Co co-doped TiO 2 postponed the anatase to rutile transformation of TiO 2 by about 200–300°C, such that before calcination at 775°C, no rutile was detected for 4 mol% Ni/Co co-doped TiO 2. A systematic decreasing on crystallite size and increasing on specific surface area of Ni/Co co-doped TiO 2 were observed. Photo-catalytic activity of anatase polymorph was measured by the decomposition rate of methylene blue under visible light. The results showed enhanced catalysis under visible light for Ni/Co co-doped TiO 2 as compared to pure TiO 2. The enhanced performance was attributed to surface chemistry change associated with a slight shift in the band gap. Depending on the temperatures ranging from 475 to 1075 °C, band gap energy of Ni and Co doped TiO 2 crystals decreased. For all samples there is a general reduction of the band gap energy from 3.00 to 2.96 eV. 相似文献
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