Enhanced efficiency and stability of inorganic CsPbBr3 perovskite solar cells based on carbon counter electrode by applying PbTiO3-coated TiO2 nanorod films as scaffold layers

The CsPbBr 3 perovskite solar cells (PSCs) based on carbon counter electrode (CCE) are promising because of the advantages including fabrication simplicity and excellent stability, but their power conversion efficiencies (PCE) are low due to interfacial carrier recombination as the direct contact of the CsPbBr 3 with electron transport materials (ETM). In this paper, PbTiO 3 shells were grown onto TiO 2 nanorods to form PbTiO 3 -coated TiO 2 scaffold layer via a two-step method. The presence of PbTiO 3 could promote crystallinity of the CsPbBr 3 perovskite film and inhibits interface recombination at the CsPbBr 3 /TiO 2 interface. Consequently, the carbon-based CsPbBr 3 solar cells with PbTiO 3 /TiO 2 scaffold layer achieves a high PCE of 7.28%, demonstrating an increase by 19.9% compared with the devices based on TiO 2 NRs. Moreover, the champion devices exhibited excellent stability in ambient air, with the PCE value remaining at 93% over 28 days.