Compact Inverse‐Opal Electrode Using Non‐Aggregated TiO₂ Nanoparticles for Dye‐Sensitized Solar Cells

Abstract

Compact inverse‐opal structures are constructed using non‐aggregated TiO2 nanoparticles in a three‐dimensional colloidal array template as the photoelectrode of a dye‐sensitized solar cell. Organic‐layer‐coated titania nanoparticles show an enhanced infiltration and a compact packing within the 3D array. Subsequent thermal decomposition to remove the organic template followed by impregnation with N‐719 dye results in excellent inverse‐opal photoelectrodes with a photo‐conversion efficiency as high as 3.47% under air mass 1.5 illumination. This colloidal‐template approach using non‐aggregated nanoparticles provides a simple and versatile way to produce efficient inverse‐opal structures with the ability to control parameters such as cavity diameter and film thickness.

Tuning the crystallinity parameters in macroporous titania films

“…Ordered macroporous titania is usually made using spherical polymer beads as structural templates. Typical protocols involve either inltra-tion of the voids of ordered bead arrays with different titania precursors (the so-called inltration method involving two main steps, the bead assembly and their subsequent impregnation with suitable titania precursors), 20,[22][23][24][25][26][27][28] or a direct coassembly of the titania precursors and the polymer beads (the so-called co-deposition method). [29][30][31][32][33][34] The polymer template is removed aer the solidication of the titania phase, leaving a porous titania replica.…”

Sandwich-structured TiO2 inverse opal circulates slow photons for tremendous improvement in solar energy conversion efficiency

“…13,14 Secondly, the uniform macroporous structure improves mass transport and reduces electron-hole recombination rate. [15][16][17] More importantly, at the edge of photonic bandgaps, the group velocity of the light is significantly slowed down, becoming anomalously small, owing to the effect of nonlinear dispersion, creating "slow photons"; when the energy of slow photons is in resonance with the absorption edge of the material which is usually of low absorbance, the photon absorption can be enhanced. [18][19][20] By matching the red or blue edge of photonic stopbands with the electronic excitation energy of the material, more than 2 fold enhancement of photocatalytic efficiency of TiO 2 has been demonstrated.…”

Preparation of Hollow Titanium Dioxide Shell Thin Films from Aqueous Solution of Ti-Lactate Complex for Dye-Sensitized Solar Cells

“…Some works on ordered and multilayered hollow TiO 2 shells, which are inverse opal structure, have shown photonic crystalline effects leading to red shift in incident photon-tocurrent conversion efficiency (IPCE). (Nishimura et al, 2003;Yip et al, 2008) Recently energy conversion efficiencies of DSSCs using inverse TiO 2 opal, including 1.8 %, (Guldin et al, 2010) 3.47 % (Kwak et al, 2009) and 4.5 % (Qi et al, 2009) have been reported. In the previous work we prepared hollow TiO 2 shell monolayer films by the electrolysis of an aqueous (NH 4 ) 2 TiF 6 solution on complicated polystyrene (PS) particles-preadsorbed substrate followed by calcination.…”