Preparation of a Nanoporous CaCO₃-Coated TiO₂ Electrode and Its Application to a Dye-Sensitized Solar Cell

Abstract

A nanoporous CaCO3 overlayer-coated TiO2 thick film was prepared by the topotactic thermal decomposition of Ca(OH)2, and its performance as an electrode of a dye-sensitized solar cell was investigated. As compared to bare TiO2, nanoporous CaCO3-coated TiO2 provided higher specific surface area and, subsequently, a larger amount of dye adsorption; this in turn increased short-circuit current (Jsc). Furthermore, the CaCO3 coating demonstrated increased impedance at the TiO2/dye/electrolyte interface and increased the lifetime of the photoelectrons, indicating the improved retardation of the back electron transfer, which increases Jsc, open-circuit voltage (Voc), and fill factor (ff). Thereby, the energy conversion efficiency (eta) of the solar cell improved from 7.8 to 9.7% (an improvement of 24.4%) as the nanoporous CaCO3 layer was coated onto TiO2 thick films.

New trends for solar cell development and recent progress of dye sensitized solar cells

“…Coating structures show their remarkable advantages when applied as photoanode materials [25][26][27]. TiO 2 coated with CaCO 3 increases efficiency from 7.84% to 9.68% [28]. Except for TiO 2 , ZnO [29], Nb 2 O 5 [30], SnO 2 [31,32], and other semiconductors with wide band gap are also being paid attention to.…”

Enhanced dye sensitized solar cell performance with high surface area thin ZnO film and PEDOT:PSS

“…One effective approach to minimize the recombination process is coating the meso-porous nanocrystalline TiO 2 films with several metal oxides, such as SrO (Yang et al, 2002), SrTiO 3 (Diamant et al, 2003), CaCO 3 (Lee et al, 2007), Nb 2 O 5 (Xia et al, 2007), MgO (Wu et al, 2008(Wu et al, , 2011, MgCl 2 (Yang et al, 2009), ZnO (Chou et al, 2012), etc., which will be shelled over the TiO 2 semiconductor. The coating of metal oxides induces energy barrier, which separates injected electrons physically from the redox couple during the transport and thereby suppresses the recombination process.…”

Mixed binder of silica nanoparticles and titanium isopropoxide for low-temperature cured titanium oxide photoanode of dye-sensitized solar cell

“…The poor necking increases the resistance of diffusion of the injected electron from excited dye molecules through the porous network of TiO 2 . Therefore, one of the general targets in the flexible DSSC study would be to find high performance low-temperature binder materials and the corresponding processing condition, which can bind the TiO 2 on flexible transparent substrate without losing overall efficiency of the device [15][16][17]. In this context, TIPP is frequently used to bind TiO 2 particles through a low-temperature sol-gel chemical process [6,18,19].…”