ABSTRACT
The all-inorganic CsPbI3 perovskite presents promising prospects due to its suitable band gap and nonvolatile nature, while serious nonradiative recombination and unmatched energy level alignment hinder its further developments. Here, a facile and effective surface treatment strategy is proposed to modify the CsPbI3 surface with ethanolamine, leading to significantly reduced defects, and ameliorated band alignment and morphology. Consequently, a champion power conversion efficiency of 18.41% with improved stability is achieved for the inverted CsPbI3 solar cells.
ABSTRACT
Hole-transporting materials (HTMs) with desired properties play a crucial role in achieving efficient and stable perovskite solar cells (PSCs). However, most high-performance devices generally employ HTMs that require additional complicated doping treatments, which are harmful to the device stability. In this work, a fluorine-substituted polymer electron-donor material, PM6, is developed as a dopant-free HTM in regular all-inorganic CsPbI2Br PSCs. Benefiting from the matched energy-level alignment, high hole mobility, and effective defect passivation, a champion power conversion efficiency (PCE) of 16.06% with an ultrahigh fill factor of 82.54% is achieved for the PM6-based PSCs. Compared to doped Spiro-OMeTAD (PCE of 14.46%), PM6 significantly enhances the PCE of CsPbI2Br PSCs with negligible hysteresis owing to its more efficient charge transportation, suppressed recombination, and strong trap passivation effect. Moreover, remarkable improvements in long-term stability, thermal stability, and operational stability are all gained for the PM6-based PSCs. In addition, the successful application of PM6 as a dopant-free HTM in organic-inorganic hybrid PSCs enables an impressive PCE of 20.05% with superb device stability, manifesting the generality of the polymer donor material in various PSC systems.
