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1.
TiO 2 nanoparticles (NP) at top of TiO 2 nanotube (TiO 2 NP@TiO 2NT) double-layered architecture is constructed to combine the advantages of TiO 2 NP and TiO 2 NT together. This composite TiO 2 NP@TiO 2NT architecture as photoanode possesses a larger surface area for more QDs loading, and highly tubular structure for electron swift transport. Based on this architecture, CdSe/CdS quantum dots (QDs) have been successfully synthesized by successive ionic layer adsorption reaction (SILAR) method for quantum dots-sensitized solar cell application. The photovoltaic performance of QDSSCs based on TiO 2 NP@TiO 2 NT have been investigated in contrast with bare TiO 2 NP and bare TiO 2 NT architectures with almost the same thickness. The results show that the power conversion efficiency (PCE) of QDSSCs could be enhanced using TiO 2 NP@TiO 2 NT and improved to 3.26%, which is 80% and 38% higher than QDSSCs based on bare TiO 2 NT and bare TiO 2 NP, respectively. The BET surface area, UV–vis absorption spectra, and incident photon to current conversion efficiency (IPCE) measurements results show the evidence that the TiO 2 NP@TiO 2 NT can combine advantages of TiO 2 NP and TiO 2 NT structures together and lead to a higher light harvesting efficiency, electron collecting efficiency, and efficient electron transport. 相似文献
2.
Multi-layered TiO 2 nanostructured films were fabricated to improve the light harvest efficiency of the dye-adsorbed TiO 2 electrode in dye-sensitized solar cells (DSSCs) by light scattering. Three different structures of TiO 2 electrodes, with layers consisting of TiO 2 pastes with average diameters of 9, 20, and 300 nm, respectively, were fabricated and their photovoltaic effects on the DSSC
devices were investigated. By utilizing the multi-layered TiO 2 electrode constructed using the three different TiO 2 pastes, the overall power conversion efficiency of the DSSC devices in the PEG-based electrolyte was increased to 5.24% under
irradiation of 100 mW/cm 2 at AM 1.5. 相似文献
3.
Titanium dioxide nanotubes (TiO 2 NTs) with various sizes have been prepared by low-temperature chemical synthesis using commercial anatase TiO 2 particles with different crystallite size in NaOH solution and used as a photoelectrode in a dye-sensitized solar cell (DSSC).
The relationship between the physicochemical properties of electrode materials and photovoltaic performance was investigated.
The electrodes made from modified TiO 2 NTs showed a strong dependency on their specific surface area and resultant amount of dye adsorption; the surface area decreased
with increase in the diameter of the NT from 9.8 to 23.6 nm. The conversion efficiency of the cell made from TiO 2 NT, 12.9 nm in diameter, was enhanced by 12% compared to that of the smallest NT. These results suggested that the photovoltaic
performance improved by the suppression of photogenerated charge recombination in spite of a 25.3% reduction in the specific
surface area. In addition, larger TiO 2 NTs could be utilized as a scattering layer on the top of the TiO 2 nanoparticulate working electrode. It was observed that this controlled TiO 2 photoelectrode architecture exhibited enhanced conversion efficiency without TiCl 4 treatment. 相似文献
4.
The rapid manufacturing of high-efficiency dye-sensitized solar cells (DSSCs) is limited by the slow dye adsorption on TiO 2 nanoparticles (NPs)-accumulated photoelectrode using conventional dip-coating process. Therefore, we aim to accelerate the adsorption of dyes that are attached on TiO 2 NPs by employing an aerosol impactor. Herein the aerosolized dyes are designed to get deposited rapidly on the TiO 2 NPs-accumulated photoelectrode. In addition, to effectively trap the irradiated sunlight in DSSCs, we assemble the photoelectrodes incorporated with bilayered TiO 2 thin films comprising small TiO 2 NPs-based underlayer and large TiO 2 NPs-based overlayer as dye-supporting and light-scattering mediums, respectively. Furthermore, the effects of dye aerosol impaction and TiO 2 stacking structures on the efficiency of DSSCs are examined. The power conversion efficiency (PCE) of DSSCs comprising a N719 dye-supporting layer treated with dip-coating process was determined as ~ 5.67%; however, when the bilayered TiO 2 thin films with an optimized thickness ratio of light-scattering overlayer and dye-supporting underlayer were coated with N719 dyes using dye aerosol impactor, the resulting PCE increased to ~ 7.46%. This suggests that the photovoltaic characteristics of DSSCs can be enhanced considerably using the effective TiO 2 NP stacking structures coated with rapid, uniform, and strong aerosol dye adsorption throughout the TiO 2-based photoelectrodes. 相似文献
5.
We developed a process for preparing SiO 2/TiO 2 fibers by means of precursor transformation method. After mixing PCS and titanium alkoxide, continuous SiO 2/TiO 2 fibers were fabricated by the thermal decomposition of titanium-modified PCS (PTC) precursor. The tensile strength and diameter
of SiO 2/TiO 2 fibers are 2.0 GPa, 13 μm, respectively. Based on X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution
transmission electron microscopy (HRTEM) measurements, the microstructure of the SiO 2/TiO 2 fibers is described as anatase–TiO 2 nanocrystallites with the mean size of ~10 nm embedded in an amorphous silica continuous phase. 相似文献
6.
Mesoporous TiO 2 nanoparticle (NP) films are broadly used as electrodes in photoelectrochemical cells, dye‐sensitized solar cells (DSSCs), and perovskite solar cells (PSCs). State‐of‐the‐art mesoporous TiO 2 NP films for these solar cells are fabricated by annealing TiO 2 paste‐coated fluorine‐doped tin oxide glass in a box furnace at 500 °C for ≈30 min. Here, the use of a nontraditional reactor, i.e., flame, is reported for the high throughput and ultrafast annealing of TiO 2 paste (≈1 min). This flame‐annealing method, compared to conventional furnace annealing, exhibits three distinct benefits. First, flame removes polymeric binders in the initial TiO 2 paste more completely because of its high temperature (≈1000 °C). Second, flame induces strong interconnections between TiO 2 nanoparticles without affecting the underlying transparent conducting oxide substrate. Third, the flame‐induced carbothermic reduction on the TiO 2 surface facilitates charge injection from the dye/perovskite to TiO 2. Consequently, when the flame‐annealed mesoporous TiO 2 film is used to fabricate DSSCs and PSCs, both exhibit enhanced charge transport and higher power conversion efficiencies than those fabricated using furnace‐annealed TiO 2 films. Finally, when the ultrafast flame‐annealing method is combined with a fast dye‐coating method to fabricate DSSC devices, its total fabrication time is reduced from over 3 h to ≈10 min. 相似文献
7.
TiO 2-based nanotubes (NTs), nanoparticles (NPs) and composite structural film (50% NP + 50% NT film) were synthesized by sol-gel hydrothermal process. Synthetic indigo dye was used as a sensitizer with the unique combination of electrolyte (EMII + BMII + PMII) and with cobalt sulphide as counter electrode. The structure and morphology of the three films, namely, NP, NT and NPNT is studied through X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The absorption spectra and incident photon-to-current conversion efficiency (IPCE) of the three films were compared and found to be higher for NPNT film. The efficiency and photocatalytic activity of three films were evaluated. The composite structure showed improved efficiency (1.72%) than NP (1%) and NT films (0.78%). The photocatalytic activity of the three films were measured using organic dye, methylene blue under UV light radiation. The composite structure showed higher dye absorption and higher rate of reaction with time. This paper certainly proves that there are many rooms to focus on the photoanode configuration, which plays a key role to improve the efficiency of dye-sensitized solar cell (DSSC). 相似文献
8.
Crystalline size and porosity of TiO 2 films are known to be easily controlled by changing acid or base catalyst concentration. This work investigates the influence of acid/base catalyst treatments of TiO 2 nanoparticles on the efficiency of dye-sensitized solar cells (DSSCs). The results indicate that the performance of DSSC fabricated with base-treated TiO 2 is remarkably better than that fabricated with acid-treated TiO 2 because of different film properties including particle size, shape, film porosity, and surface structure and electron transport phenomena. 相似文献
9.
Rafts of aligned, high aspect ratio TiO 2 nanotubes were fabricated by an electrochemical anodization method and their axial electrical conductivities were determined
over the temperature range 225–400 °C. Length, outer diameter, and wall thickness of the nanotubes were approximately 60–80 μm,
160 nm, and 30 nm, respectively. Transmission electron microscopy studies confirmed that the TiO 2 nanotubes were initially amorphous, and became polycrystalline anatase after heat treatment at temperatures as low as 250 °C
in air. The activation energy for conductivity over the temperature range 250–350 °C was found to be 0.87 eV. The conductivity
values are comparable to those of nanocrystalline and nanoporous anatase thin films reported in literature. 相似文献
10.
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
11.
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
12.
N/TiO 2, S/TiO 2, and N S/TiO 2 nanocrystalline films anode were obtained by doping non-metallic element N and S which could change the LUMO of anode, leading
to the easy injection of electron from the excited state of dye molecule to the conduction band of semiconductor, and thus
improving the photoelectric conversion efficiency and reducing the impedance of solar cells. The anode films treated by titanium
tetrachloride and co-sensitized by P3HT/N719 were also studied. The absorption region of P3HT/N719 covered the entire visible
region in the solar cells. The solar cell based on N/TiO 2 anode film treated by titanium tetrachloride and P3HT/N719 showed a short-circuit current density of 10.20 mA/cm 2, open-circuit voltage of 0.557 V, and photoelectric conversion efficiency of 2.55%. 相似文献
13.
Anatase TiO 2 nanotubes (NTs) with the diameter of about 12 nm and the length of several hundreds nanometers were synthesized by hydrothermal method. The samples were characterized by X-ray diffraction (XRD), transmitting electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmet–Teller (BET) measurements. The NTs are used to make composites photoanode with pristine TiO 2 nanoparticles in dye-sensitized solar cells (DSSCs). It was found that the NT/nanoparticle ratio had a pronounced impact on the performance of solar cells. The electrode composite has better photoelectric properties than the full nanoparticle and NTs solar cells. The optimum content NTs, was found to be 5%, at which content the incident photon to current efficiency was about 63.1%, an 13.8% increment compared to that using full P25 under the same condition. 相似文献
14.
Physical properties of the TiO2 and Au-doped TiO2 films fabricated by sol–gel dip-coating route are investigated. The diffraction peaks of XRD spectra confirmed the formation of anatase phase. Crystallite size was found to be decreased by increasing dopant concentration from 12.02 to 10.10 nm. All the thin films annealed in air exhibit significant room-temperature ferromagnetism displaying anatase phase that can be employed in spintronic devices. The saturation magnetization increases from 6.8 to 10.35 emu/cm3 with the increase in Au concentration. The coercivity values vary between 360.82 and 478.515 Oe and remnant magnetization ranges between 0.46 and 0.71 emu/cm3. Dielectric parameters obeyed Maxwell-Wagner model and Koop’s theory and were explained by hopping mechanism. Small values of dielectric constant made them favorable for high-frequency devices. The band gaps of the undoped and Au-doped TiO2 thin films is in the range 3.5 to 3.38 eV, which are lesser than those of reported pure TiO2 (3.7 eV) that is favorable for enhancing solar cells efficiency. Au-doped TiO2 leads to an optimum antimicrobial agent. The photocatalysts having 5 wt% Au exhibit the highest photoactivities. The degradation of methylene blue under sunlight made them promising materials for water treatment. 相似文献
15.
Ordered porous TiO 2 thin films were fabricated on conductive glass by using colloid crystal template of polystyrene (PS) spheres. Microstructural characterization by scanning electron microscopy techniques was carried out to explore the porous structural changes due to the PS templates which could be controlled by adjusting the drawing rate. Photovoltaic performance was measured and this revealed the effect of microstructural changes. The results showed that monolayer porous TiO 2 films and multilayer porous TiO 2 films could be successfully prepared. And multilayer porous TiO 2 films provided large surface area for dye absorption to increase the efficiency of dye-sensitized solar cells (DSSCs) which were assembled by porous TiO 2 films. 相似文献
16.
A novel configuration of hybrid solar cells fabricated using TiO 2 and in situ polymerization of poly(3-hexylthiophene), or P3HT, on the surface of TiO 2 is reported. Comparison of UV–Vis absorption and current/voltage (I/V) characteristics of devices with or without in situ
polymerized P3HT layer were discussed, and the surface morphology of TiO 2/in situ polymerized P3HT film was investigated by AFM in the contact mode. The short-circuit current density and energy conversion
efficiencies of device with in situ polymerized P3HT layer were higher by 6 times and 3 times compared to that of device without
the in situ polymerized P3HT layer. By adding poly (ethylene dioxythiophene)-poly (styrene sulfonic acid)(PEDOT-PSS) layer
under the top contact, device showed a short-circuit current density of 1.27 mA cm −2, an open-circuit voltage of 0.52 V, a fill factor of 0.24, and a energy conversion efficiency of 0.16% at AM 1.5 solar illumination
(100 mW cm −2). 相似文献
17.
Nanocrystalline TiO 2 thin films have been successfully synthesized by controlled precipitation route. These films are further annealed at 623 K
for 2 h. The change in structural, morphological, optical, and wettability properties are studied by means of X-ray diffraction
(XRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM), optical absorption, and contact angle
measurement. From the XRD pattern it is clear that the as-grown TiO 2 films are amorphous in nature which becomes polycrystalline after annealing. The FTIR study reveals the formation of TiO 2 compound. Scanning electron micrographs shows that the as-grown TiO 2 film consists of agglomerated nanograins well covered to the substrate surface which gets converted into vertical nanorods
after annealing. As-deposited and annealed TiO 2 films showed hydrophilic behavior as water contact angles were 24° and 32°, respectively. The optical absorption study reveals
the small red shift due to annealing and attributed to grain size. The annealed TiO 2 film showed conversion efficiency of 0.037% in photoelectrochemical cell with 1 M NaOH electrolyte. 相似文献
18.
In the present study dye sensitized solar cells (DSSCs) have been fabricated with a tri-layer photo anode consisting of hydrothermally prepared titania nano tubes (TNT) having a diameter of 9-10 nm and length of several micrometers as outer layer, P25 TiO 2 powder as transparent light absorbing middle layer and a compact TiO 2 inner layer to improve the adhesion of different layers on a transparent conducting oxide coated substrate. In comparison to cells fabricated using TNTs or P25 alone, the tri-layer DSSCs exhibit an enhanced efficiency of 7.15% with a current density of 17.12 mA cm − 2 under AM 1.5 illumination. The enhancement is attributed to the light scattering generated by TNTs aggregates, reduction in electron transport resistance at the TiO 2/dye/electrolyte interface and an improvement in electron life-time. 相似文献
19.
TiO 2 nanoparticle (NP), composite TiO 2 nanoparticle–nanorod (NP–NR) and bi-layer TiO 2 nanoparticle/nanorod (NP/NR) with the optimized diameter of NRs had been prepared as anode layer in dye-sensitized solar cells (DSSCs). Morphology and thickness of anode layers were provided by field emission scanning electron microscope (FE-SEM) and scanning electron microscopy (SEM) devices. Current density–voltage diagrams were prepared by potentiostat and solar simulator devices at air mass (AM) 1.5. It is determined that DSSCs based on composite NP–NR photoelectrode had the best conversion efficiency of 5.07%. Also, the results of the electrochemical modelling of these DSSCs indicated that solar cells based on NP–NR electrode had the highest electron transport time ( τ d) of 312.87 ms, electrons’ recombination lifetime ( τ n) of 130.4 ms and the lowest transfer resistance ( R ct) as well as transport resistance ( R t) of 22.46 and 9.4 Ω, respectively. 相似文献
20.
TiO 2 nanorod (NR) and nanotube (NT) arrays grown on transparent conductive substrates are attractive electrode for solar cells. In this paper, TiO 2 NR arrays are hydrothermally grown on FTO substrate, and are in situ converted into NT arrays by hydrothermally etching. The TiO 2 NR arrays are reported as single crystalline, but the TiO 2 NR arrays are demonstrated to be polycrystalline with a bundle of 2–5 nm single crystalline nanocolumns grown along [001] throughout the whole NR from bottom to top. TiO 2 NRs can be converted to NTs by hydrothermal selective etching of the (001) core and remaining the inert sidewall of (110) face. A growth mechanism of the NR and NT arrays is proposed. Quantum dot‐sensitized solar cells (QDSCs) are fabricated by coating CdSe QDs on to the TiO 2 arrays. After conversion from NRs to NTs, more QDs can be filled in the NTs and the energy conversion efficiency of the QDSCs almost double. 相似文献
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