TiO2 nanorods branched on fast-synthesized large clearance TiO2 nanotube arrays for dye-sensitized solar cells

A large clearance TiO2 nanotube arrays (LTAs) has been synthesized by a not more than 12 h anodization duration and based on this a branched TiO2 nanotube arrays (BLTs) has been achieved through TiO2 nanorods branch-like grown on the LTAs. Some key factors and probable mechanisms of the fabrication processes on two novel nanoarchitectures are discussed. Exhilaratingly, it is found that the obtained LTAs has demonstrated large pore diameter and void spaces (pore diameter ∼350 nm; void spaces ∼160 nm; and tube length ∼3.5 μm), and the synthesized hierarchical BLTs, compared with conventional TiO2 nanotube arrays, has shown a much stronger dye absorption performance and an approximately double of the solar cell efficiency (in our case from 1.62% to 3.18% under simulated AM 1.5 conditions).

Graphical AbstractThe schematic diagram of synthesis process for LTAs and BLTs is on the above and the corresponding FESEM images of obtained photoanodes samples are shown below.Figure optionsDownload as PowerPoint slideHighlights
► Large clearance TiO2 nanotube arrays (LTAs) was synthesized by a fast anodization process of 12 h.
► Anodization time of 12 h is just 10% of about 120 h reported in the previous references.
► Branch-like TiO2 nanotube arrays (BLTs) was achieved by growing TiO2 nanorods on the LTAs.
► Obtained BLTs and LTAs show impressive morphology and noticeable improvement of surface area.
► BLTs shows about more than 1 times higher solar cell efficiency than that of TiO2 nanotube arrays.