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The introduction of large-volume amines (LVAs) in Sn-based perovskite films has been shown to lead to promising power conversion efficiency (PCE) in Pb-free perovskite solar cells (PSCs). However, the LVAs adopted so far (e.g., phenylethylammonium [PEA] and butylammonium [BA]) are insulating and could impede charge extraction within the perovskite film. Herein, a conjugated LVA, 3-phenyl-2-propen-1-amine (PPA), is introduced in formamidinium tin iodide (FASnI3) perovskite. Our results show that the incorporation of PPA results in enlarged grain sizes, reduced trap density, preferential orientation, efficient charge extraction, and enhanced structural stability of FASnI3film. These positive effects help in achieving efficient PSCs with a PCE as high as 9.61% with negligible hysteresis and outstanding stability (remains 92% of its initial PCE value after 1,440 h). Furthermore, the presence of PPA enables a self-healing action of PSCs. Most importantly, we report large-area (1 × 1 cm2) Sn-based PSCs achieving PCE of 7.08%.

Emerging all-inorganic perovskite nanocrystals can retain a desired crystal structure under ambient conditions and offer easy solution processability. In this work, we have demonstrated CsPbI3perovskite quantum dot (QD) solar cells with a remarkable efficiency approaching 13% and an extremely low energy loss of 0.45 eV by employing a series of dopant-free polymeric hole-transporting materials (HTMs). The CsPbI3QD solar cells use polymer HTMs to achieve efficient charge extraction at QD/polymer interfaces and avoid device instability caused by complex doping and oxidation processes required by conventional Spiro-OMeTAD. Meanwhile, the CsPbI3QD photovoltaic devices can be fabricated at room temperature and exhibit more reproducible film quality, showing potential advantages over current all-inorganic thin-film perovskite solar cells. We believe that our findings will catalyze the development of new device structures, specifically for perovskite QDs, and help realize the promising potential of all-inorganic perovskite solar cells.