A N‐Ethylcarbazole‐Terminated Spiro‐Type Hole‐Transporting Material for Efficient and Stable Perovskite Solar Cells. Issue 20 (19th September 2022) - Han, Mingyuan
Abstract: The development of stable and efficient hole‐transporting materials (HTMs) is critical for the commercialization of perovskite solar cells (PSCs). Herein, a novel spiro‐type HTM was designed and synthesized where N ‐ethylcarbazole‐terminated groups fully substituted the methoxy group of spiro‐OMeTAD, named spiro‐carbazole. The developed molecule exhibited a lower highest occupied molecular orbital level, higher hole mobility, and extremely high glass transition temperature ( T g =196 °C) compared with spiro‐OMeTAD. PSCs with the developed molecule exhibited a champion power conversion efficiency (PCE) of 22.01 %, which surpassed traditional spiro‐OMeTAD (21.12 %). Importantly, the spiro‐carbazole‐based device had dramatically better thermal, humid, and long‐term stability than spiro‐OMeTAD. Abstract : Terminal groups matter : A spiro‐typed hole‐transporting material (spiro‐carbazole) with N ‐ethylcarbazole units as terminal groups is designed. It exhibits lower highest occupied molecular orbital level, higher glass transition temperature and hole mobility, as well as better hydrophobicity than conventional spiro‐OMeTAD, leading to better device efficiency and stability in perovskite solar cells.