Ultrafast laser-annealing technique for the fabrication of large-grain perovskite films and efficient perovskite solar cells at room temperature.

Sn–Pb mixed perovskites with bandgaps in the range of 1.1–1.4 eV are ideal candidates for single‐junction solar cells to approach the Shockley–Queisser limit. However, the efficiency and stability of Sn–Pb mixed‐perovskite solar cells (PSCs) still lag far behind those of Pb‐based counterparts due to the easy oxidation of Sn2+. Here, a reducing agent 4‐hydrazinobenzoic acid is introduced as an additive along with SnF2 to suppress the oxidation of Sn2+. Meanwhile, a vertical Pb/Sn compositional gradient is formed spontaneously after an antisolvent treatment due to different solubility and crystallization kinetics of Sn‐ and Pb‐based perovskites and it can be finely tuned by controlling the antisolvent temperature. Because the band structure of a perovskite is dependent on its composition, graded vertical heterojunctions are constructed in the perovskite films with a compositional gradient, which can enhance photocarrier separation and suppress carrier recombination in the resultant PSCs. Under optimal fabrication conditions, the Sn–Pb mixed PSCs show power conversion efficiency up to 22% along with excellent stability during light soaking.

Scalable, high efficiency, floating graphene membranes for seawater desalination.

A polyferroplatinyne polymer can be patterned on the surface of Si wafer in ordered nanoline or nanodot shapes with PDMS molds through nanoimprint lithography (NIL), and subsequent thermal treatment gives rise to the nanopatterned arrays of L1(0) -FePt nanoparticles with the same periodicities. The method offers excellent potential to be utilized in the simple and rapid fabrication of bit patterned media for magnetic data recording.