Investigation into Photoconductivity in Single CNF/TiO2-Dye Core–Shell Nanowire Devices

A vertically aligned carbon nanofiber array coated with anatase TiO2 (CNF/TiO2) is an attractive possible replacement for the sintered TiO2 nanoparticle network in the original dye-sensitized solar cell (DSSC) design due to the potential for improved charge transport and reduced charge recombination. Although the reported efficiency of 1.1% in these modified DSSC’s is encouraging, the limiting factors must be identified before a higher efficiency can be obtained. This work employs a single nanowire approach to investigate the charge transport in individual CNF/TiO2 core–shell nanowires with adsorbed N719 dye molecules in dark and under illumination. The results shed light on the role of charge traps and dye adsorption on the (photo) conductivity of nanocrystalline TiO2 CNF’s as related to dye-sensitized solar cell performance

Recombination in nanophase TiO2 films

Recombination and transport parameters were determined in Schottky diodes made of thin TiO2 solgel films with particle size around 50 nm. Effective recombination times are typically in the range, 10 amp; 956;s lt; amp; 964; lt;1 ms, depending on injection level. The lifetimes are found to decrease at higher current levels, indicating bimolecular recombination kinetics due to a progressive increase in trap occupation. The mobility lifetime product is estimated to be amp; 8776;5 10 amp; 8722;11 cm2 V and is independent of current leve