*2.1. Material Preparation*

The perovskite (PbI2, MAI), FTO glasses (3 × 3 cm2) and the hole transport layer (HTL) ((Spiro-MeOTAD, lithium-bis (tri-fluoromethanesulfonyl) imide (Li-TFSI), and 4-tertbutylpyridine (tBP)) solution were purchased from Xi'an Polymer Light Tech-nology Co., Ltd. (Xian,China) 3,4-ethylenedioxythiophene (EDOT), graphite, acidic (NH4)2S2O8 (APS), TiCl4, DMSO (99.9%) and 4-hydroxybutyric acid lactone (DMF) (99.9%) were purchased from Aladdin. Acetone, ethanol, and isopropyl alcohol were purchased from Sinopharm Chemical Reagent Co., Ltd. (Sinopharm Chemical Reagent Co., Ltd. ) And all the materials were used as received without further purification.
