As a superstars of photovoltaic devices, organic–inorganic hybrid perovskite solar cells (PSCs) have garnered plenty of interest due to their superior character. However, many defects, such as carrier recombination, inferior stability, poor interface contact, have prevented their further development. Here, we demonstrate a novel approach of interface engineering to form a compact perovskite layer with decreased defects on SnO2 film by adding tris­(pentafluorophenyl)­boron (TPFPB) as an interfacial modification layer, which validly improves the interface performance and enhances the crystallinity of MAPbI3. Hence the planar MAPbI3 PSCs with TPFPB modification show fast charge transfer and low trap state density with an enhanced champion power conversion efficiency (PCE) from the original of 16.92% to 19.41%, as well as long-term stability with 80.7% of its initial PCE after 1000 h of aging in N2 atmosphere without encapsulation, while the pristine one only shows 68.9% of the original PCE. The results reveal that TPFPB can be used as an effective interface modification layer for high efficiency and stability PSCs, and it maybe also be used in other devices due to its superior interface modification for high quality crystallinity thin films.

CsPbX 3 perovskite QDs can be adjusted by controlling size, morphology and com position. In addition, they have exhibited high PLQY, narrow FWHM, strong defect resistance, long carrier lifetime, and PL tunability in the entire visible spectrum range, all of which render this category of materials broad prospects in the field of optoelectronic applications. [7][8][9][10] However, owing to its ionic nature, perovskite QDs are highly susceptible to phase transition and even decomposi tion under various stimulus, including radiation, heat, moisture, oxygen. [11] Such instability problem greatly hinders the practical applications of lead halide perovskite. Besides, high defect density is often reported for colloidal perovskite QDs. These structural and surface defects would destroy the crystalline lattice of CsPbX 3 QDs, making them more vul nerable to external stimuli, and resulting in the rapid degradation of their photo electric performance. [12,13] Moreover, because of their large surface area and rich surface defective sites, inorganic perovskite QDs prepared by colloidal approach often show poor storage stability with high susceptiblity to agglomeration, thus restricting their potential commercial application. [14,15] All-inorganic perovskite quantum dots (QDs) have emerged as a new category of low-cost semiconducting luminescent materials for optoelectronic applications. However, their poor stability has become the main challenge that impedes their potential applications. Herein, Ni-doped CsPbBr 3 QDs with lead phosphate (Pb 3 (PO 4 ) 2 ) shell through surface sacrificial coating (c-Ni-CsPbBr 3 ) have been developed based on a modified thermal injection approach. The synergistic effect of Ni doping and Pb 3 (PO 4 ) 2 coating effectively improves the stability and optical performances of CsPbBr 3 QDs, including photoluminescence (PL) intensity, the average lifetime, and PL quantum yield (QY). Thus, the c-Ni-CsPbBr 3 QDs demonstrate the full width at half maxima (FWHM) and PLQY being 18.42 nm and 90.77%, respectively. The PL intensity of c-Ni-CsPbBr 3 can be maintained at 81% of its original value after being heated at 100 °C for 1 h. No phase transformation can be observed after being stored under ambient conditions (25 °C, 60% relative humidity (RH)) for 21 days. In addition, by combining green c-Ni-CsPbBr 3 QDs, red CdSe-based QDs and the blue GaN chip, a QD enhancement film (QDEF) is fabricated to form a liquid crystal display (LCD) backlit with a wide color gamut covering cover 121% of the National Television System Committee (NTSC) standard.

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