Enhanced photovoltaic property and stability of perovskite solar cells using the interfacial modified layer of anatase TiO2 nanocuboids

The substrates were significant for fabricating the high performance and outstandingly stable perovskite solar cells (PSCs) due to the influences of films growth and pores filling. In this paper, we study the effects of interface modification with TiO2 nanoparticles (NPs) and nanocuboids (NCs) synthesized by the TiCl4 and NaF/TiCl4 solution, prepared on nanorods (NRs) substrates, on the PSCs performance. The devices modified with NPs and NCs exhibit power conversion efficiency (PCE) of 12.97% and 15.56%, respectively, which are 1.3 and 1.5 times greater than that of the untreated cell (10.29%). By carefully analyze the photovoltaic parameters, the improvements in the open-circuit voltage (V-oc) and fill factor (FF) can be attributed to the optimization of the interfacial properties of perovskite-titania and the quality of perovskite films after the surface treatment. The novel TiO2 NCs obtained by NaF/TiCl4 treatment were found to expose highly reactive (001) facets, which may promote the absorption of perovskite materials due to the more effective area, resulting in the increment of short-circuit current density (J(sc)) compared to simplex TiCl4 treatment. In addition, the device modified by the NCs shows the higher stability in the air atmosphere than other devices.