Cyclopentadithiophene-Based Hole-Transporting Material for Highly Stable Perovskite Solar Cells with Stabilized Efficiencies Approaching 21%
Seçkin Akın, Michael Bauer, Ryusuke Uchida, Neha Arora, Gwénolé Jacopin, Yuhang Liu, Dirk Hertel, Klaus Meerholz, Elena Mena‐Osteritz, Peter Bäuerle, Shaik M. Zakeeruddin, M. Ibrahim Dar, Michaël Grätzel
Abstract
There is an urge to develop new hole-transporting materials (HTMs) for perovskite solar cells (PSCs), which can yield comparable power conversion efficiencies (PCEs) yet mitigate the issue of stability associated with the state-of-the-art HTM spiro-MeOTAD. Herein, we designed and prepared C2v-symmetric spiro-configured HTM-1 comprising a central acridine–cyclopentadithiophene core unit flanked with triarylamine moieties. PSCs containing a 40 nm thin HTM-1 layer for hole extraction yielded a stabilized PCE approaching 21% under standard illumination. Owing to its higher hole mobility (μh) at low electric field, an impressive short-circuit current density (JSC) of 24.7 mA cm–2 and a high fill factor (FF) of 0.77 have been achieved. More importantly, HTM-1-based PSCs presented an excellent long-term operational stability under continuous illumination for 400 h and thermal stability at 80 °C, which can be ascribed to its high glass transition temperature of 168 °C and superior moisture tolerance. Arguably, the confluence of high performance and remarkable stability will lead to the development of technologically interesting new, stable, and efficient PSCs.