Hybrid Titania Photoanodes with a Nanostructured Multi-Layer Configuration for Highly Efficient Dye-Sensitized Solar Cells

Abstract

To construct a hybrid titania photoanode containing nanoparticles and nanorods of varied size in a multilayer (ML) configuration for dye-sensitized solar cells, the essence of our ML design is a bilayer system with additional layers of nanorods of well-controlled size inserted between the transparent and the scattering layers to enhance the light-harvesting capability for photosensitizers with small absorptivity, such as Z907. We measured charge-extraction and intensity-modulated photoelectric spectra to show the advantages of one-dimensional nanorods with an improved electron-transport property and an upward shift of the potential band edge; a favorable ML configuration was constructed to have a cascade potential feature for feasible electron transport from long nanorods, to normal nanorods, to small nanoparticles. On the basis of the ML system reported herein, we demonstrate how the performance of a Z907 device is improved to attain η ∼10%, which is a milestone for its future commercialization.

Dye-Sensitized Solar Cells with Anatase TiO2Nanorods Prepared by Hydrothermal Method

“…It is known that large-size TiO 2 particles have the advantage of strong light scattering ability, while small size TiO 2 particles have the advantages of large contact area and low contact resistance [18][19][20][21][22][23][24]. In order to take the advantages of both the strong light scattering and the large contact area/low contact resistance, we constructed a triple-layer TiO 2 DSSC 6 International Journal of Photoenergy Figure 8(a) shows the cross-sectional scanning electron microscopy (SEM) images of TiO 2 thin films with triple-layer structures.…”

“…In addition, it is known that the strong back-scattering light due to the large particles near the conducting glass results in a light loss. To reduce light loss due to this strong back-scattering light, multiple-layer structure of TiO 2 with 2 International Journal of Photoenergy different particle sizes has been proposed in the past [21][22][23][24][25][26][27].…”

TiO2 nanotube structures for the enhancement of photon utilization in sensitized solar cells

“…For example, TiO 2 NTs feature excellent electron recombination and collection properties but suffer from insufficient internal surface areas for dye adsorption, while TiO 2 NPs show the opposite characteristics. To realize photoanodes with these multi-functions simultaneously to promote solar cell performances, multi-layered (two, three or more layers) structures can be designed, in which nanostructures of various morphologies and sizes are combined together in series, and each layer plays different roles in photon to electron conversion processes, including sufficient dye adsorption, fast electron diffusion and proper light recycling [98,[171][172][173][174][175][176].…”

Utilization of Size-Controlled Squid Ink Particles as Enhancer for the Porosity of Titania Electrode in Dye-Sensitized Solar Cell

“…TiO 2 particles with a diameter of a few hundred nanometers have been continually used for scattering layers, because such large particles can diffuse visible light. [29][30][31] In the TiO 2 film electrodes using large particles, dye aggregation occurred on intergranular pores owing to the physical adsorption of the dye molecule, which was responsible for the low electron injection yield. 32) If one fabricated an active layer consisting of TiO 2 particles with a diameter of approximately 30 nm, further enhancement of the PCE would be expected.…”