Highly-flexible graphene transparent conductive electrode/perovskite solar cells with graphene quantum dots-doped PCBM electron transport layer

In recent years, organic-inorganic hybrid perovskite solar cells (PSCs) have received strong attention due to their high power conversion efficiency (PCE) and low cost. Here, we first employ 3-aminopropyl triethoxysilane (APTES)-treated graphene (GR) as a transparent conductive electrode (TCE) and quantum dots (GQDs)-doped phenyl C61 butyric acid methyl ester (PCBM) as an electron transport layer (ETL) for flexible PSCs. By increasing the concentration of GQDs to 2.5 mg/L, the PCE of the PSCs with GR/APTES TCE increases up to 16.4 and 15.0% on rigid and flexible substrates, respectively due to the reduced charge recombination at the ETL/perovskite interface and improved conductivity of the ETL. The flexible PSCs exhibit excellent bending stability by maintaining similar to 80% of the original PCE even after 3000 bending cycles at a curvature radius of 4 mm, resulting from the improved flexibility by the APTES interlayer.