Surface engineering has been shown critical for the success of perovskite solar cells by passivating the surface enriched defects and mobile species. The discovery of surface modulators with superior interaction strength to perovskite is of paramount importance since they can retain reliable passivation under various environments. Here, we report a chelation strategy for surface engineering of CsPbI 2 Br perovskite, in which dithiocarbamate molecules can be coordinate to surface Pb sites via strong bidentate chelating bonding. Such chelated CsPbI 2 Br perovskite can realize excellent passivation of surface under-coordinated defects, reaching a champion power conversion efficiency of 17.03% and an open-circuit voltage of 1.37 V of CsPbI 2 Br solar cells. More importantly, our chelation strategy enabled excellent device stability by maintaining 98% of their initial efficiency for over 1400 h in ambient condition. Our findings provide scientific insights on the surface engineering of perovskite that can facilitate the further development and application of perovskite optoelectronics.

Fe2TiO5 is recognized as a novel photoanode material for solar water splitting. However, it has been seldom studied as a photoelectrode by itself, and its practical performance still needs to be improved. Herein, nanostructured Fe2TiO5 photoanode is prepared by the electrospray technique. The effects of the synthesis parameters on the photoelectrochemical water splitting activity are studied including the substrate temperature and film thickness. In addition, surface F-modification is applied on pure Fe2TiO5 to further improve its photoelectrochemical performance. Also, the water splitting photocurrent of F-treated Fe2TiO5 increases to 0.4 mA cm-2 at 1.23 VRHE, which is higher than that of pristine Fe2TiO5. X-ray photoelectron spectroscopy confirms the formation of surface Ti-F bonds after surface F-treatment, which facilitates the transfer of holes and the breakage of O-H bond under illumination. The enhanced performance can be attributed to a synergetic effect of nanoarchitecture and surface F-modification. Therefore, the nanoarchitecture assisted by surface F-modification offers an effective strategy to prepare high-efficiency nanostructured complex metal oxides for solar water splitting.

A highly efficient Pd-catalyzed Sonogashira coupling of various aryl fluorides with terminal alkynes in the presence of LiHMDS was developed. Both unreactive electron-rich fluoroarenes and electron-poor fluoroarenes proceeded smoothly and afforded the corresponding internal alkynes in moderate to excellent yields.

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