Perovskite solar cell based on network nanoporous layer consisted of TiO2 nanowires and its interface optimization

•3D TiO2 network nanoporous structure consisted of 1D nanowires is fabricated on FTO.•One-step sintering can reduce the interface defects and enhance the fill factor.•A novel in-situ method is studied for the preparation of porous scaffold layer.•The new 3D porous scaffold layer is superior to TiO2 nanoparticle film.•The efficiency of perovskite solar cell based on this structure reaches up to 12.78%.

Anatase TiO2 film with 3D network nanoporous structure consisted of 1D nanowires is obtained on SnO2:F (FTO) glass substrate by in-situ hydrothermal synthesis and applied in mesoporous perovskite (CH3NH3PbI3) solar cell. A thin Ti film is deposited on FTO substrate by magnetron sputtering before the hydrothermal treatment with sodium hydroxide solution. Then, a layer of network nanoporous TiO2 (NT) film is formed. The efficiency of perovskite solar cell based on this 3D structure with one-step sintering can be optimized to 9.19%. The NT film consisted of 1D TiO2 nanowires is beneficial to the transmission of charge carriers and the infiltration of hole transport material. And this one-step sintering process can reduce the interface defects and enhance the fill factor of the device. Then, we further optimize the surface of NT layer through TiCl4 post-treatment. The post-treatment can optimize the carrier separation and the deposition of perovskite layer, thus improving the open-circuit voltage (Voc) and short-circuit current density (Jsc) of perovskite solar cell. As a result, the value of Jsc gets an enhancement of 45.63% and the efficiency of perovskite solar cell reaches up to 12.78%.