Structurally Stabilized Organosilane‐Templated Thermostable Mesoporous Titania. Issue 1 (4th December 2013)

• Record Type: Journal Article
• Authors: Amoli, Vipin; Tiwari, Rashmi; Dutta, Arghya; Bhaumik, Asim; Sinha, Anil Kumar
• Is Part Of: Chemphyschem. Volume 15:Issue 1(2014)
• Page Start: 187
• Page End: 194
• Publication Date: 2013-12-04
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201300872
• Languages: English
• ISSNs: 1439-4235

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Structurally thermostable mesoporous anatase TiO<sub>2</sub> (m‐TiO<sub>2</sub>) nanoparticles, uniquely decorated with atomically dispersed SiO<sub>2</sub>, is reported for the first time. The inorganic Si portion of the novel organosilane template, used as a mesopores‐directing agent, is found to be incorporated in the pore walls of the titania aggregates, mainly as isolated sites. This is evident by transmission electron microscopy and high‐angle annular dark field scanning transmission electron microscopy, combined with electron dispersive X‐ray spectroscopy. This type of unique structure provides exceptional stability to this new material against thermal collapse of the mesoporous structure, which is reflected in its high surface area (the highest known for anatase titania), even after high‐temperature (550 °C) calcination. Control of crystallite size, pore diameter, and surface area is achieved by varying the molar ratios of the titanium precursor and the template during synthesis. These mesoporous materials retain their porosity and high surface area after template removal and further NaOH/HCl treatment to remove silica. We investigate their performance for dye‐sensitized solar cells (DSSCs) with bilayer TiO<sub>2</sub> electrodes, which are prepared by applying a coating of <italic>m</italic>‐TiO<sub>2</sub> onto a commercial titania (P25) film. The high surface area of the upper mesoporous layer in the P25–<italic>m</italic>‐TiO<sub>2</sub> DSSC significantly increases the dye loading ability of the photoanode. The photocurrent and fill factor for the DSSC with the bilayer TiO<sub>2</sub> electrode are greatly improved. The large increase in photocurrent current (ca. 56 %) in the P25–<italic>m</italic>‐TiO<sub>2</sub> DSSC is believed to play a significant role in achieving a remarkable increase in the photovoltaic efficiency (60 %) of the device, compared to DSSCs with a monolayer of P25 as the electrode.</p> </abstract>