High-performance planar perovskite solar cells based on low-temperature solution-processed well-crystalline SnO2 nanorods electron-transporting layers

Abstract

Low-temperature solution-processed method is a kind of low-energy-consuming and simple methodology for preparing cost-effective planar perovskite solar cells (PSCs). A key factor affecting photovoltaic performance of planar PSCs is the quality of electron-transporting layers (ETLs) in the devices. Although TiO2 is the most widely used material for preparing ETLs, it has drawbacks such as low electron mobility and ultraviolet light induced photocatalysis. So the replacement of TiO2 in ETLs is an important strategy to improve the stability and photovoltaic performance of PSCs. Here, the fabrication of high-performance planar PSCs based on low-temperature solution-processed well-crystalline SnO2 nanorods ETLs is reported. The sophisticated solvothermal method with the aid of oleic acid (OA) ligands is used to synthesize high aspect ratio and well crystalline SnO2 nanorods. And then the OA-capped SnO2 nanorods are directly used to fabricate ETLs without complex treatments. The planar PSCs based on OA-capped SnO2 nanorods ETLs achieve a champion power conversion efficiency of 18.62%, which is much higher than that of the ones based on OA-capped TiO2 nanorods ETLs (14.27%). Compared to the OA-capped TiO2 nanorods, the insulating OA ligands show weaker influence on the electronic properties of SnO2 nanorods, owing to the high electron mobility character of SnO2.