Photoelectrochemical performance and carrier lifetime of electrodes based on MWCNT-templated TiO2 nanoribbons

Abstract

Electron lifetime and photoelectrochemical performance of carbon-doped TiO 2 electrodes are presented. Thin films of random disposed ribbon-like structures of C-doped TiO 2 were applied onto FTO substrates using spray and dip-coating techniques. The fabricated electrodes show photocurrent enhancement 20 times greater than compact TiO 2 electrode, and electron lifetimes 2 orders of magnitude lower than compact TiO 2 films. Enhancement in photocurrent suggests a beneficial role of C-doping which compensates the transport properties expected to deteriorate in disordered and thicker architectures. Due to its large surface area, C-doped TiO 2 electrodes can be used as matrix for the deposition of QD sensitizers for photovoltaic applications or as photoanode for photocatalytic applications. Still optimization on film thickness and passivation strategies must be implemented to increase the carrier lifetime.

Optically Controlled TiO2-Embedded Supercapacitors: The Effects of Colloidal Size, Light Wavelength, and Intensity on the Cells’ Performance

“…Typically, small TiO 2 colloids exhibit optical lifetime on a scale of <1 ns [ 23 ]. On the other hand, photo-electrochemical lifetimes for compacted submicron TiO 2 electrodes are on the scale of seconds [ 24 ]. Thus, it seems that micron-sized colloids exhibit even longer lifetimes: the electrode resistance did not change much upon illumination ( Figure 9 ); Figure 7 b indicates a capacitance peak at a scan rate of 0.05 V/s or a cycle of 20 s; therefore, the RC constant indicates an optically related capacitance change on a scale of 10 s of seconds.…”