One-Step, Surfactant-Free Hydrothermal Method for Syntheses of Mesoporous TiO₂Nanoparticle Aggregates and Their Applications in High Efficiency Dye-Sensitized Solar Cells

Abstract

A facile, one-step, template-less, surfactant-free hydrothermal process, using a metal salt as the precursor, is developed to prepare submicrometer sized mesoporous TiO 2 nanoparticle aggregates (NPGs). The as-prepared TiO 2 NPGs are crystalline of the anatase phase, with a high specific surface area of 166 m 2 /g, an average pore size of 8.9 nm, and an average NPG size of 840 nm. With these NPGs, a new form of composite photoanode, consisting of the mesoporous TiO 2 NPGs and xerogels, is proposed for high efficiency dye-sensitized solar cells (DSSCs). TiO 2 xerogels are incorporated into the TiO 2 NPGs layer with an impregnation process to form the TiO 2 NPGs/xerogels composite. A high power conversion efficiency of 8.41% is achieved for DSSCs based on the TiO 2 NPGs/xerogels composite photoanode, representing a 38% efficiency boost over the efficiency of 6.11% achieved with a P25 TiO 2 based cell. The success of the present composite TiO 2 nanostructure can be attributed to the effective utilization of the inter-NPG space with the infiltration of the TiO 2 xerogels, the excellent structural connectivity within and across the NPG and xerogel domains for fast electron transport, the high specific surface areas of both the NPGs and xerogels for providing abundant dye adsorption for generation of photoinduced electrons, the formation of a TiO 2 xerogel blocking layer on top of the photoanode substrate, and the submicrometer size of the NPGs for much improved light harvesting efficiency. This new type of composite photoanode, different from the 0D/1D nanostructure based ones, proves effective by taking structural advantages from both constituent nanostructures, the mesoprous NPGs and xerogels, and opens up a new way of thinking in the structural design of the photoanodes.

Improving interfacial electron transfer and light harvesting in dye-sensitized solar cells by using Ag nanowire/TiO2 nanoparticle composite films

“…2 compares the Nyquist plots of electrochemical impedance spectra of DSSCs equipped with the pure P25 photoanode and the photoanodes containing different amounts of AgNWs@TiO 2 . These spectra were fitted according to the model described in the literatures 25,26 and the obtained results are summarized in Table 1. As indicated, the impedance of both the electron transfer at TiO 2 /dye/electrolyte interface (R 2 ) and the ion diffusion in electrolyte (W S ) gradually decreased with increasing AgNWs@TiO 2 contents in the photoanode to the maximum extent of 3 wt% (25% for R 2 and 21% for W S ).…”

Low doses of TiO2-polyethylene glycol nanoparticles stimulate proliferation of hepatocyte cells

“…[5] Consequently, various methods have been developed to prepare TiO 2 NPs, including sol-gel techniques,[6] hydrothermal methods,[7] and solvothermal methods. [8] However, widespread use of TiO 2 NPs has raised concerns about potential risks to human health, livestock, and the ecosystem due to long-term exposure and environmental release.…”

Electrochemiluminescence modified electrodes based on RuSi@Ru(bpy)32+ loaded with gold functioned nanoporous CO/Co3O4 for detection of mycotoxin deoxynivalenol

“…Nanoporous metal materials are synthesized by many routes including hydrothermal method (Cheng et al 2012), template method (Lee et al 2014) and dealloying method (Erlebacher et al 2001;Xu et al 2011). Dealloying method has been proved to be a simple and effective way to fabricate three-dimensional nanoporous materials by selective dissolution of the most active elements out of alloys (Dan et al 2013;An et al 2013;Rizzi et al 2014).…”