Improved Electron Diffusion Coefficient in Electrospun TiO₂ Nanowires

Abstract

TiO 2 nanowires with a diameter of ∼150 nm, length of ∼3-4 µm, and aspect ratio of 10:1, were prepared by ultrasonically dispersing electrospun continuous nanofibers in monocarboxylic acids. The resulting pastes were used for making nanowire films on conducting glass substrates with thicknesses in the range of 500 nm to 100 µm, good adhesion, and high nanowire packing. These films were used to fabricate dye-sensitized solar cells using the D131 dye and the iodide/triiodide electrolyte. Transient photocurrent measurements showed a high electron diffusion coefficient in those nanowire films. The measured diffusion coefficient in those TiO 2 nanowires was orders of magnitude higher than that observed in nanoparticles under similar experimental conditions. The charge-transport mechanism in the nanowire sample is discussed in support with the measured open-circuit voltage decay curves.

Enhanced photocatalytic H2-production activity of bicomponent NiO/TiO2 composite nanofibers

“…It was worth noting that the fiberous morphology of the samples was well preserved after the calcination. The closely contacted NPs during the calcination enabled the electrons to move easily from one grain to another and provided an effective electron transfer pathway on TiO 2 [40]. The efficient interparticle charge transfers along the well-aligned TiO 2 1D framework would benefit for the photocatalytic H 2 production [41,42].…”

Effects of multi-element dopants of TiO2 for high performance in dye-sensitized solar cells

“…The electron transport time ( t ) and the electron recombination time ( r ) can be estimated by from the IMPS and IMVS plots by following Eqs. (4) and (5) [42,43]:…”

“…In addition, the electron diffusion coefficient (D n ) and the electron diffusion length (L n ) can be determined on the basis of film thickness (d, 4 m in this study), t and r by following Eqs. (6) and (7) [42][43][44]:…”

High-efficiency dye-sensitized solar cells based on electrospun TiO2 multi-layered composite film photoanodes

“…Park et al optimized the electrospinning process by the introduction of acetyl acetone instead of acetic acid, and the fabricated DSSCs devices based on photoelectrode composed of nanoparticles and electrospun nanorods showed improved light-electricity conversion efficiency of 3.25% [20]. It was reported that 1D electrospun TiO 2 exhibits good photovoltaic characteristics highly depending on the size and aspect ratio [21]. Therefore, engineering the microstructure and architectures of 1D electrospun TiO 2 provides opportunities on further enhancing its photovoltaic performance.…”