Dopant-free methoxy substituted copper(II) phthalocyanine for highly efficient and stable perovskite solar cells

Many researches manifest that the presences of dopant and additive in hole transport layer (HTL) accelerate the degradation of perovskite solar cell (PSC). Therefore, in terms of enhancing stability, it is promising to develop dopant-free hole transport materials (HTMs). Herein, a methoxy substituted copper(II) phthalocyanine CuPc-(OMe)(8) was synthesized and successfully applied as dopant-free HTM in the PSCs. The optimized PSC devices based on the dopant-free CuPc-(OMe)(8) achieve the highest efficiency of 18.3%, which is competitive with traditional doped Spiro-OMeTAD. More importantly, an impressively superior long-term stability is represented by dopant-free CuPc-(OMe)(8) based device. These results highlight that CuPc-(OMe)(8) is a promising dopant-free HTM for application in PSCs.