In Situ Combined-Hole Transport Layer for Highly Efficient Perovskite Solar Cells

Spiro-OMeTAD is a commonly used material in perovskite solar cells (PSCs). It requires chemical doping with a lithium compound and 4-tert-butylpyridine to enhance its conductivity and hole extraction efficiency. However, this conventional doping process has limitations in terms of efficiency and stability. In this study, an innovative approach using an in situ combined dual-hole transport layer with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-Pn) is introduced to improve PSC performance. These results show that this in situ combined hole transport layer with TIPS-Pn channels effectively extracts and transports hole carriers, reducing non-radiative recombination. Additionally, it allows for the absorption of excess photo energy from hot hole carriers, resulting in a significant increase in the average power conversion efficiency of PSCs from 22.42% to 24.13%. Furthermore, the device retains 90% of its initial efficiency after 1900 h of exposure to air, indicating improved stability. Notably, a 44% improvement in thermal stability is observed after 500 h due to the robust morphology and hydrophobic surface. This work presents a novel strategy for enhancing the performance of Spiro-OMeTAD in PSCs and provides valuable insights into hole carrier dynamics in perovskite-based optoelectronic devices.