Fabrication of TiO2/CuSCN Bulk Heterojunctions by Profile-Controlled Electrodeposition

We demonstrate a facile bottom-up growth of CuSCN — a widely used hole conducting material, in mesoscopic TiO 2 films by electrodeposition in the presence of TiO 2 compact layer. The profile-controlled growth of CuSCN in the nanopores of mesoscopic TiO 2 is realized by judiciously optimizing the electrolyte concentration and applied potential, so that the effective electron diffusion length in TiO 2 is much shorter than film thickness and the electrodeposition is strictly confined within very narrow region from the conducting substrate. The TiO 2 /CuSCN heterojunctions exhibit a pore filling ratio of ∼80% and show good rectifying properties, which is anticipated to be an important step forward to the facile fabrication of bulk heterojunction for nanostructured solar cells or 3D batteries.