2 research outputs found
Chemical Interaction, Space-Charge Layer, and Molecule Charging Energy for a TiO<sub>2</sub>/TCNQ Interface
Three driving forces control the
energy level alignment between
transition-metal oxides and organic materials: the chemical interaction
between the two materials, the organic electronegativity, and the
possible space charge layer formed in the oxide. This is illustrated
in this study by analyzing experimentally and theoretically a paradigmatic
case, the TiO<sub>2</sub>(110)/TCNQ interface; due to the chemical
interaction between the two materials, the organic electron affinity
level is located below the Fermi energy of the <i>n</i>-doped
TiO<sub>2</sub>. Then, one electron is transferred from the oxide
to this level and a space charge layer is developed in the oxide,
inducing an important increase in the interface dipole and in the
oxide work function
Increasing Photocurrents in Dye Sensitized Solar Cells with Tantalum-Doped Titanium Oxide Photoanodes Obtained by Laser Ablation
Laser ablation is employed to produce vertically aligned
nanostructured
films of undoped and tantalum-doped TiO<sub>2</sub> nanoparticles.
Dye-sensitized solar cells using the two different materials are compared.
Tantalum-doped TiO<sub>2</sub> photoanode show 65% increase in photocurrents
and around 39% improvement in overall cell efficiency compared to
undoped TiO<sub>2</sub>. Electrochemical impedance spectroscopy, MottāSchottky
analysis and open circuit voltage decay is used to investigate the
cause of this improved performance. The enhanced performance is attributed
to a combination of increased electron concentration in the semiconductor
and a reduced electron recombination rate