Kaya, Ismail CihanOzdemir, ResulUsta, HakanSonmezoglu, Savas2025-09-252025-09-2520222050-74882050-7496https://doi.org/10.1039/d2ta01541bhttps://hdl.handle.net/20.500.12573/3065Sonmezoglu, Savas/0000-0002-6011-3504; Ozdemir, Resul/0000-0002-7957-110X; Kaya, Ismail Cihan/0000-0003-0773-0391;In this study, for the first time, n-i-p PSCs were fabricated using dopant-free 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as the solution-processed hole transporting layer (HTL). The power conversion efficiency (PCE) of the optimized device with the C8-BTBT film that favored edge-on molecular alignment was 22.45% with negligible hysteresis. A thinner dopant-free C8-BTBT HTL effectively protected the perovskite layer from moisture resulting in better shelf-life stability for un-encapsulated PSCs, which maintained >80% of its initial PCE (after a period of 120 days) at a relative humidity level of 40-45%. In addition, the C8-BTBT-based PSCs kept their high performance with no obvious PCE loss at 60 degrees C for 20 days in the ambient atmosphere and retained 82% of their initial PCE at 85 degrees C for 10 days. Overall, our findings revealed that a thin solution-processed C8-BTBT HTL plays a critical role not only in hole extraction and transport but also in greatly improving the ambient and thermal stability of n-i-p PSCs.eninfo:eu-repo/semantics/openAccessArticle10.1039/d2ta01541b2-s2.0-85131751110