TiO2 hierarchical pores/nanorod arrays composite film as photoanode for quantum dot-sensitized solar cells

Power conversion efficiency (PCE) of quantum dot-sensitized solar cells (QDSSCs) was boosted in a TiO2 composite film (TCSF) with delicate design in structure where TiO2 hierarchical porous film (THPF) situated on the top of TiO2 nanorod arrays film (TNAF). In this case, TNAF could supply efficient scattering centers for high light harvesting and direct electrical pathways for fast electron transfer while the THPF could offer porous channels for loading high quantity of previously synthetized quantum dots (QDs) and facilitate the penetration of electrolyte. Meanwhile, in this specific configuration, the presence of anatase-rutile heterojunction at the interface could help the rutile TNAF layer to efficiently collect photo-injected electrons from the anatase THPF layer thus suppressing the recombination of electrons and holes in electrolyte. The results showed that the PCE of QDSSC based on the TNAF photoanode was about 1.4-fold higher (eta =3.05%, J(sc) = 15.86mA cm(-2), V-oc = 0.602 V, FF = 0.319) than that of device based on pure THPF (eta= 2.20%, J(sc) = 13.82 mA cm(-2), V-oc = 0.572 V, FF = 0.278). (C) 2018 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.