Preparation of Zr-doped mesoporous TiO2 particles and their applications in the novel working electrode of a dye-sensitized solar cell

Abstract This paper presents an implementation of our recent theory on the suspension of electron-hole recombination via electronic- and micro-structure optimization to study the influence of Zr-doping on the efficiency ( η ) of TiO 2 -based dye-sensitized solar cells (DSSCs). We developed a four-layered working electrode, in which the size of particles increased from the bottom layer of TiO 2 (P-25) through three successive layers of Zr-doped TiO 2 , which were calcined at 450, 600, and 850 °C respectively. The enhancement in open-circuit photovoltage ( V oc ) and short-circuit photocurrent density ( J sc ) can be attributed to the electronic- and micro-structures in the working electrode. The former is related to band bending, whereas the latter is related to light-scattering within multiple layers. Simulation results (FactSage) demonstrate that Zr doping in TiO 2 can suspend or delay the formation of oxygen vacancies and thereby reduce the number of electron scattering centers, which helps to suspend electron-hole recombination by strengthening Ti-O bonds. The proposed four-layered working electrode produced an 80.2% increase in η , compared with DSSCs using a TiO 2 (P-25) electrode. This study demonstrated a novel metal doping strategy for the manipulation of electronic structure and photoelectron conversion efficiency. The proposed methodology could also be used to guide the design of photo-catalysts in general.