Hierarchical TiO₂ Photoanode for Dye-Sensitized Solar Cells

Abstract

Hierarchical or one-dimensional architectures are among the most exciting developments in material science these recent years. We present a nanostructured TiO(2) assembly combining these two concepts and resembling a forest composed of individual, high aspect-ratio, treelike nanostructures. We propose to use these structures for the photoanode in dye-sensitized solar cells, and we achieved 4.9% conversion efficiency in combination with C101 dye. We demonstrate this morphology beneficial to hamper the electron recombination and also mass transport control in the mesopores when solvent-free ionic liquid electrolyte is used.

Maximizing omnidirectional light harvesting in metal oxide hyperbranched array architectures

“…It is well known that the key to high solar-to-electric efficiency is surface area. Nevertheless, for the 1D nanostructure-based electrode, a fundamental drawback is the insufficient internal surface area and thus low dye-loading capacity owing to a low roughness factor or the considerable free space between adjacent 1D nanostructures 18,19 . One of the approaches to increase the surface area for improving the device performance is to increase the length of 1D nanostructures 20 .…”

TiO2: A Critical Interfacial Material for Incorporating Photosynthetic Protein Complexes and Plasmonic Nanoparticles into Biophotovoltaics

“…Vertically aligned TiO 2 nanotube arrays have been successfully produced by potentiostatic anodization of titanium metal in a fluoride containing electrolyte and exhibit larger electron diffusion length [23]. A forest-like photoanode combining efficient light trapping and high surface area for dye absorption was synthesized via fine control of pulse laser deposition, which consists of hierarchical assemblies of nanocrystalline particles of anatase TiO 2 [24]. This hierarchical architecture was demonstrated to suppress electron recombination with tri-iodide along with increase of electron lifetime and perform no hindering in mass transport using ionic liquid electrolyte.…”

A Review on Current Status of Stability and Knowledge on Liquid Electrolyte-Based Dye-Sensitized Solar Cells

“…The optimization of this charge collection efficiency has been the stake in research activities in the mesostructuration of the photoanode or by introducing additional point defects through aliovalent doping. The reduction of particles dimensionality offers faster electron transport when the photoanode is composed of vertically aligned nanowires or nanotubes [63][64][65][66][67][68][69][70][71]. The synthesis of TiO 2 beads leads to the most spectacular improvements resulting from the excellent particles interconnections, shortened mass transport pathways into the mesopores, and combination of light scattering ability and high surface area offering improved light confining properties of the photoanode [16,[72][73][74].…”