Graphene/SrTiO3 nanocomposites used as an effective electron-transporting layer for high-performance perovskite solar cells

Abstract

Organic–inorganic perovskite solar cells based on binary oxides have been studied for a long time and have obtained an impressive advance in performance. However, studies using ternary oxides as the electron-transporting layer are scarce and there are still many problems to be solved. The ternary oxide SrTiO₃ with a perovskite structure is well matched with the perovskite absorber layer in the crystal structure. Although the device based on mesoporous-SrTiO₃ (mp-SrTiO₃) showed a high V_oc, its average J_sc is still too low compared with mp-TiO₂ based devices. In this work, we used graphene/SrTiO₃ nanocomposites as an effective electron-transporting layer. Due to the superconductivity of the graphene combined with tuning the amount of the starting graphene to increase the light harvesting of the absorber layer and decrease recombination centers, we got a great achievement. The device based on graphene/SrTiO₃ nanocomposites exhibited a PCE of 10% with a J_sc of 18.08 mA cm⁻², increased by 46.0 and 45.6% respectively compared with the mp-SrTiO₃ based device, indicating incorporation of graphene is an effective way to improve the J_sc of mp-SrTiO₃ based perovskite solar cells.