TiO2 hierarchical porous film constructed by ultrastable foams as photoanode for quantum dot-sensitized solar cells

It reported a novel and simple method for the first time to prepare TiO2 hierarchical porous film (THPF) using ultrastable foams as a soft template to construct porous structures. Moreover, dodecanol as one foam component was creatively used as solvent during the synthesis of CdSe quantum dots (QDs) to decrease reaction temperature and simplify precipitation process. The result showed that hierarchical pores in scale of microns introduced by foams were regarded to benefit for high coverage and unimodal distribution of QDs on the surface of THPF to increase the efficiencies of light-harvesting, charge collection and charge-transfer. The increased efficiencies caused an enhancement in quantum efficiency of the cell and thus remarkably increased the short circuit current density (J(sc)). In addition, the decrease of charge recombination resulted in the increase of the open circuit voltage (V-oc) as well. The QDSSC based on THPF exhibited about 2-fold higher power conversion efficiency (eta = 2.20%, J(sc) = 13.82 mA cm(-2), V-oc = 0.572 V) than that of TiO2 nanoparticles film (TNF) (eta = 1.06%, J(sc) = 6.70 mA cm(-2), V-oc = 0.505 V). It provided a basis to use foams both as soft template and carrier to realize simultaneously construction and in-situ sensitization of photoanode in further work. (C) 2016 Elsevier B.V. All rights reserved.