Tio₂ Paste Formulation for Crack-Free Mesoporous Nanocrystalline Film of Dye-Sensitized Solar Cells

Abstract

Using a doctor-blade method, a highly viscous titanium dioxide (TiO2) paste was deposited on a glass substrate coated with fluorine doped tin oxide (FTO). The paste was mainly composed of commercially available TiO2 nanoparticles (P25) and hydroxypropyl cellulose (HPC) as organic filler. Varying the content of HPC in the TiO2 paste changed the physical properties of the mesoporous TiO2 layer, particularly its porosity and surface area. From the quantification of dyes on Ti2, layer and the electrochemical impedance spectroscopy (EIS) study of the dye-sensitized solar cells (DSSCs), the surface area of the TiO2 film was found to have decreased. This came with the increase of HPC content while the porosity of the film increased, consistent with the concurrent decrease of short-circuit current density (Jsc) and efficiency (eta). The increased porosity greatly affected the electron transport through the TiO2 film by decreasing the coordination number of the TiO2 particles resulting to a decrease of the electron diffusion coefficient.

Emerging polymorphism in nanostructured TiO2: Quantum chemical comparison of anatase, rutile, and brookite clusters

“…These three forms all consist of sixfold coordinated Ti atoms and threefold coordinated O atoms, but with different arrangements of neighboring TiO 6 octahedral units sharing O atoms . Nanostructured TiO 2 materials are furthermore often found experimentally to contain a mixture of different forms, and in particular mixtures of amorphous TiO 2 , anatase, and rutile are common in commercially available pastes such as P25 …”

Low-Temperature Chemical Sintered TiO2 Photoanodes Based on a Binary Liquid Mixture for Flexible Dye-Sensitized Solar Cells

“…Before preparing the TiO 2 pastes, the TiO 2 powder (Degussa P25) was pre-treated with acetylacetone to minimize NPs aggregation [9]. Then, 1 g of pretreated TiO 2 powder was mixed with two compositions of 1-octanol and CCl 4 (1:1 and 1:0 (v/v)) and stirred at room temperature (RT) for 6 h. Subsequently, the mixture was homogenized for another 30 min to obtain homogenous dispersion of TiO 2 NPs by using an ultrasonic horn.…”

“…The preparation of TiO 2 photoanodes for conventional high-efficiency g-DSSCs fabrication requires the use of organic binders such as polyethylene glycol, ethylcellulose, and hydroxypropyl cellulose. These binders increase the viscosity of the TiO 2 pastes and enable the preparation of highly stable, crack-free, and homogenous mesoporous TiO 2 (mp-TiO 2 ) films with a thickness of > 10 µm [9,10]. During the sintering process at 500ºC, these organic binders are burned out and facilitate the formation of mp-TiO 2 layers.…”

“…During the sintering process at 500ºC, these organic binders are burned out and facilitate the formation of mp-TiO 2 layers. In addition, this process induces the development of excellent electrical pathways for transporting photo-injected electrons by improving the interparticle connection of TiO 2 and the adhesion of the TiO 2 layer with glass/FTO substrates [9][10][11]. However, the conventional binder containing TiO 2 pastes and the high-temperature sintering methods are unsuitable for fabricating transparent conducting oxide-coated plastic substrates-based flexible DSSC (f-DSSC) [8].…”

Probing the stoichiometry dependent catalytic activity of nickel selenide counter electrodes in the redox reaction of iodide/triiodide electrolyte in dye sensitized solar cells

“…Similarly, theoretical calculations for I 3 À /I À redox process suggest that the metal sites in a metal chalcogenide are more active compared to the chalcogenides sites. 20,21 This implies that the stoichiometric ratio of the metal in the compound largely affect the catalytic activity. This implies that the catalytic activity of the Ni x Se y series increases towards the reduction of I ); all these were purchased from Sigma Aldrich.…”