LAUSR

The preparation of suitable hole transport material (HTM) is critical to the performance and stability of perovskite solar cells (PSCs) with low-cost. Herein, a mass producible and soluble copper phthalocyanine decorated with butoxy donor groups (CuPc-OBu) was designed as HTM and prepared by a facile two-step synthetic route. To generate high quality HTM film, 4-tertbutylpyridine (tBP) was doped into CuPc-OBu to prepare the film and then removed by annealing. Such a tBP-assisted strategy resulted in the best efficiency of the PSCs with lead trihalide perovskite up to 19.0% (small-area of 0.1 cm 2 ) and 10.1% (the active area of 8.0 cm 2 for the module device). And the best efficiency of the tin-based PSCs with CuPc-OBu reached to 6.9%. More importantly, the device with CuPc-OBu as HTM revealed the remarkably enhanced stability. This work provides a new strategy to improve the film-quality of free-doping HTMs and enhance the efficiency and stability of Pb- and Sn-based PSCs with low-cost.