Herewe report a solution-processing strategy to stabilize the perovskite-based heterostructure. Strong Pb-Cl and Pb-O bonds formed between a [CH(NH2)(2)](x)[CH3NH3](1-x)Pb1+yI3 film with a Pb-rich surface and a chlorinated graphene oxide layer. The constructed heterostructure can selectively extract photogenerated charge carriers and impede the loss of decomposed components from soft perovskites, thereby reducing damage to the organic charge-transporting semiconductors. Perovskite solar cells with an aperture area of 1.02 square centimeters maintained 90% of their initial efficiency of 21% after operation at the maximum power point under AM1.5G solar light (100 milliwatts per square centimeter) at 60 degrees C for 1000 hours. The stabilized output efficiency of the aged device was further certified by an accredited test center.