The impact of non-uniform photogeneration on mass transport in dye-sensitised solar cells

摘要: Following the introduction of cobalt(II/III)tris(2,2′-bipyridyl)-based redox mediators, dye-sensitised solar cells (DSSCs) have greatly advanced in power conversion efficiency (PCE). However, significant limiting factors include fast electron recombination and slow mass transport oxidised mediator ([Co(bipy)3]3+). In this work, effect non-uniform photogeneration on [Co(bipy)3]3+ through an electrolyte-infiltrated mesoporous TiO2 film was investigated. Different illumination conditions were used to control profile subsequent spatial distribution throughout film. They included parameters such as light intensity, substrate–electrode/electrolyte–electrode (SE/EE) direction, wavelength, photoanode thickness. Using large small optical perturbation photocurrent transients, kinetics with analysed time domain. Importantly, strong SE-absorption shown significantly contribute gradual depletion at counter electrode, along increased thickness resulting excess 10−2–1 s timescale. Furthermore, charge extraction current decay transients showed that a substantial amount can accumulate inside film, collecting fluorine-doped tin oxide (FTO) contact 10−3–10−2 The sub-linear scaling intensity leads deviating trends measurements. Mass limitations losses FTO be reduced by maximising absorption from EE-side, which increase PCE reduce J–V hysteresis.