All-inorganic perovskite solar cells (PVSCs) have drawn increasing attention because of their outstanding thermal stability. However, their performance is still inferior than the typical organic-inorganic counterparts, especially for the devices with p-i-n configuration. Herein, we successfully employ a Lewis base small molecule to passivate the inorganic perovskite film, and its derived PVSCs achieved a champion efficiency of 16.1% and a certificated efficiency of 15.6% with improved photostability, representing the most efficient inverted all-inorganic PVSCs to date. Our studies reveal that the nitrile (C-N) groups on the small molecule effectively reduce the trap density of the perovskite film and thus significantly suppresses the non-radiative recombination in the derived PVSC by passivating the Pb-exposed surface, resulting in an improved open-circuit voltage from 1.10 V to 1.16 V after passivation. This work provides an insight in the design of functional interlayers for improving efficiencies and stability of all-inorganic PVSCs.
Three amphiphilic block copolymers are employed to form polymeric micelles and function as nanocarriers to disperse hydrophobic aggregation‐induced emission (AIE) dyes, 1,1,2,3,4,5‐hexaphenylsilole (HPS) and/or bis(4‐(N‐(1‐naphthyl) phenylamino)‐phenyl)fumaronitrile (NPAFN), into aqueous solution for biological studies. Compared to their virtually non‐emissive properties in organic solutions, the fluorescence intensity of these AIE dyes has increased significantly due to the spatial confinement that restricts intramolecular rotation of these dyes and their better compatibility in the hydrophobic core of polymeric micelles. The effect of the chemical structure of micelle cores on the photophysical properties of AIE dyes are investigated, and the fluorescence resonance energy transfer (FRET) from the green‐emitting donor (HPS) to the red‐emitting acceptor (NPAFN) is explored by co‐encapsulating this FRET pair in the same micelle core. The highest fluorescence quantum yield (∼62%) could be achieved by encapsulating HPS aggregates in the micelles. Efficient energy transfer (>99%) and high amplification of emission (as high as 8 times) from the NPAFN acceptor could also be achieved by spatially confining the HPS/NPAFN FRET pair in the hydrophobic core of polymeric micelles. These micelles could be successfully internalized into the RAW 264.7 cells to demonstrate high‐quality fluorescent images and cell viability due to improved quantum yield and reduced cytotoxicity.