Niobium Doping Enhances Charge Transport in TiO₂ Nanorods

Abstract

The charge-transport behavior of nanostructured titanium dioxide (TiO 2 ) is of great interest because of the wide range of applications. In this work, we demonstrate a facile approach to improve electron transport in TiO 2 nanorods (NRs) by introducing niobium (Nb) dopant into the lattice of TiO 2 . The TiO 2 -NRs doped with Nb were grown directly on fluorine doped tin oxide (FTO) substrates by a facile hydrothermal method and used directly as the photoanodes for water oxidation. The TiO 2 nanorod electrode doped with 0.25 % of Nb showed 65 % improvement in photocurrent as compared with the pristine TiO 2 nanorod electrode. Furthermore, by simply changing the light illuminating direction, the improvement of charge transport induced by Nb doping could be easily identified.

Plasmon‐Dictated Photo‐Electrochemical Water Splitting for Solar‐to‐Chemical Energy Conversion: Current Status and Future Perspectives

“…), which only absorb UV light that accounts for merely 5% of the solar spectrum, and high recombination rate of photogenerated electron–hole charge carriers. To solve these problems, diverse strategies have been developed including structure and/or morphology engineering for improving light trapping and shortening the travel distance of charge carriers to their surfaces, elemental doping to induce the formation of intraband gap state, sensitizing the semiconductor with organic dyes or narrow‐band‐gap quantum dots to improve the visible light absorption, (4) construction of heterostructures or heterojunctions, and (5) optimization of the crystal structure . Nonetheless, it is worth noting that possible formation of undesirable defects at the interface and unfavorable stability of photosensitizers may occur in the above‐mentioned strategies, which eventually retard the fabrication of highly efficient semiconductor‐based photoelectrodes.…”

3D FTO/FTO‐Nanocrystal/TiO2 Composite Inverse Opal Photoanode for Efficient Photoelectrochemical Water Splitting

“…Among the TiO 2 ‐based nanostructured photoanodes without further combination of low bandgap semiconductors or other visible light sensitizers, the PEC performance of the as‐prepared FTO/FTO‐NC/TiO 2 composite IO electrode belongs to the forefront, as shown in Table 1 . The high conductivity of the FTO/FTO‐NC IO provides direct and fast electron transfer pathways, while the high specific surface area of such periodical host skeleton enables loading of sufficient photoactive materials and effective light scattering inside the structure, so the as‐prepared FTO/FTO‐NC/TiO 2 composite IO electrode exhibits higher photocurrent than that of considerable reported nanostructured TiO 2 electrodes . Although the photocurrent of the as‐prepared FTO/FTO‐NC/TiO 2 composite IO electrode is not the best, the utilization of conductive FTO/FTO‐NC IO skeleton with high specific surface area to boost PEC efficiency of TiO 2 offered a general solution to enhance PEC performance of existing semiconductors.…”

“…However, the practical solar‐to‐hydrogen efficiency of TiO 2 is substantially restricted by its low electron mobility, short minority carrier diffusion length, and its large bandgap . In the past decades, a great amount of research was focused on issues such as metal element doping to improve the charge transport properties, structural design, and surface modification . Recently, constructing composite semiconductor nanostructures with use of two or more similar materials has been regarded as another effective approach to enhance the charge separation and light absorption and hence enhance the overall PEC efficiency .…”

Mesoscale Confinement Effects and Emergent Quantum Interference in Titania Antidot Thin Films

“…Our work has identified the emergent charge transport properties inherent to a connected and periodic nanoscale geometry. This contrasts with disconnected periodic geometries, such as nanorods, 22,23 and connected aperiodic mesoscale geometries, such as mesoporous films. 24 We investigate the transport behavior of patterned and unpatterned titania films using impedance spectroscopy, electron holography, and in situ transmission electron microscopy (TEM) biasing experiments, enabling the reconstruction of the local electric potential.…”

“…Our work has identified the emergent charge transport properties inherent to a connected and periodic nanoscale geometry. This contrasts with disconnected periodic geometries, such as nanorods, , and connected aperiodic mesoscale geometries, such as mesoporous films …”