[en] The microstructure design of TiO₂ nanoparticles for photoanodes is an important issue in optimization of dye-sensitized solar cell (DSSC) performance. Up to date, the nanostructured TiO₂ particles have been extensively employed as active layers. However, less attention has been focused on the development of various TiO₂ nanostructures as the light-scattering layers (LSLs). In the present work, a facile hydrothermal method was utilized to prepare quasi-cube TiO₂ (qcTiO₂) nanoparticles as the LSL for the DSSC photoanode. The anatase qcTiO₂ nanoparticles had a size distribution of 30–60 nm. The photoconversion efficiency of the cell with the qcTiO₂ LSL was enhanced 12 %, compared to the TiO₂ film without a scattering layer. The above enhancement was further vindicated by the incident photon-to-current efficiency measurement. The effect of the qcTiO₂ LSL on electron transport and charge recombination of the DSSC was studied by electrochemical impedance spectroscopy. The experiment results revealed that the enhanced photovoltaic performance is attributed to the better light-harvesting capacity, longer electron life time, and less charge recombination of the qcTiO₂ nanoparticles

[en] One dimensional TiO₂ nanotube structure recently plays an important role in the application of dye sensitized solar cells (DSSCs) due to its faster electron transport. The fabrication of photoanode using the TiO₂ nanotube structures mixed with the TiO₂ nanoparticles was investigated to enhance the photovoltaic efficiency of DSSCs by increasing the surface area of electrode. In this work, self-organized and vertically-oriented TiO₂ nanotube arrays (TNAs) covered with uniformly distributed TiO₂ nanocubes (TNCs) were fabricated in a simple one-step anodization process. The X-ray diffraction patterns reveal that both TNAs and TNCs are in anatase phase. The scanning electron microscopy analysis demonstrates that the wall thickness and inner diameter of hexagonal close-packed TiO₂ nanotubes from chemically polished Ti foils are 10–15 and 100–120 nm, respectively, and the particle size of TNCs is 60–75 nm. The DSSC fabricated by the mixed morphological TNAs with TNCs shows an enhanced photoconversion efficiency of ∼ 63% than that of TNAs alone, due to the increase of both dye adsorption and electron transportation rate. - Highlights: ► Fabrication of TiO₂ nanotube arrays on Ti foils was performed using anodization process. ► Nitrogen blow influences the growth of TiO2 nanocube particles on the TiO₂ nanotube arrays. ► Mixed morphological nanotube–nanocube TiO₂ photoanode in dye-sensitized solar cell achieved improved efficiency of 1.98%

[en] In this work, the dye sensitized solar cells (DSSCs) were fabricated with bilayered structure TiO₂ based photoelectrodes, active and composite light scattering layers. The photoconversion efficiencies of these cells were significantly greater than those of the cells made by single active layered TiO₂ films. The composite scattering layers consist of mixed commercial TiO₂ particles (ST41) and anatase TiO₂ nanoparticles (NPs). The effect of scattering layer composition (ST41:NP weight ratio) on the photovoltaic performance of DSSCs has also been investigated. The best photoconversion efficiency of DSSC was 9.02% (open circuit voltage (V_oc) = 0.76 V, short-circuit photocurrent density (J_sc) = 17.6 mA/cm², fill factor (FF) = 0.68) for ST41 + NP cell (40% ST41 and 60% NPs) with the TiO₂ film thickness of 15.3 μm, which was 58% enhancement compared with the TiO₂ film without scattering-layered TiO₂. The scattering layer effect was vindicated by the incident photon-to-current conversion efficiency measurement. - Highlights: ► We constructed bilayer TiO₂ electrodes for dye-sensitized solar cells. ► An anatase TiO₂ active layer and a composite TiO₂ scattering layer formed the bilayer. ► Mixture of commercial and hydrothermally synthesized TiO₂ nanoparticles was used. ► The best photoconversion efficiency obtained in this work was 9.02%