Graphical Abstract
![](https://wqketang.oss-cn-beijing.aliyuncs.com/zip-unzip/zip-f7b60434-cad7-4ea2-85e3-41e7ed849ae8/nr-8-8-2474/files/nr-8-8-2474-FE1.jpg?Expires=1739912818&OSSAccessKeyId=STS.NTvWNG6BrfAXAFVm85YS6dMhj&Signature=df4IUaL2nrklI4YkzRtArbqVIqg%3D&security-token=CAISywJ1q6Ft5B2yfSjIr5fDHPTz251T0YOzQ2DniThgVdwai4jDiDz2IHtKenhsBOsbtfk1mG5W5%2FgZlqJ9SptIAEfJa9d99MyEKKUj2tCT1fau5Jko1beHewHKeTOZsebWZ%2BLmNqC%2FHt6md1HDkAJq3LL%2Bbk%2FMdle5MJqP%2B%2FUFB5ZtKWveVzddA8pMLQZPsdITMWCrVcygKRn3mGHdfiEK00he8TouufTinpHMskGA1Aell7Mvyt6vcsT%2BXa5FJ4xiVtq55utye5fa3TRYgxowr%2Fwo0v0YpGya5YzHXwcPskvdKZbo78UqLQlla6w%2BGqFJqvPxr%2Fp8t%2Fx5fWJKAezhVgs8cVM8JOjIqKOscIsihsPk7ATWcD1LXoQ6vH1ZZ5%2FAzVZaVWUEMpNqcRxTMldXaQqhSZT8m3upKXzOJeX7ls9%2Fv%2FV7p2s06gHUTzDnGoABahy5BlbrBXr6Ybboln3HKkGMI8p5rY4gnAiIMkq1%2FFkDMbnUGwENWKvQ05sT%2BH4IV5s147ilZIubT3EimEEK7FVolwN0Chpd5FMh0iJPLAMSrbe2knHRNhZimDskS3xbxrPuo8PyMGsJyeQZ2uLTpevxvPhQ%2BU3CqQnKuxl%2FgwUgAA%3D%3D)
Ultrathin polythiophene films prepared via electrochemical polymerization is successfully used as the hole-transporting material, substituting conventional HTM-PEDOT: PSS, in planar p-i-n CH3NH3PbI3 perovskite-based solar cells, affording a series of ITO/polythiophene/CH3NH3PbI3/C60/BCP/Ag devices. The ultrathin polythiophene film possesses good transmittance, high conductivity, a smooth surface, high wettability, compatibility with PbI2 DMF solution, and an energy level matching that of the CH3NH3PbI3 perovskite material. A promising power conversion efficiency of about 15.4%, featuring a high fill factor of 0.774, open voltage of 0.99 V, and short-circuit current density of 20.3 mA·cm-2 is obtained. The overall performance of the devices is superior to that of cells using PEDOT: PSS. The differences of solar cells with different hole-transfer materials in charge recombination, charge transport and transfer, and device stability are further investigated and demonstrate that polythiophene is a more effective and promising hole-transporting material. This work provides a simple, prompt, controllable, and economic approach for the preparation of an effective hole-transporting material, which undoubtedly offers an alternative method in the future industrial production of perovskite solar cells.
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