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Perovskite oxides and organic–inorganic halide perovskite materials, with numerous fascinating features, have been subjected to extensive studies. Most of the properties of perovskite materials are dependence on their ferroelectricity that denoted by remanent polarization (Pr). Thus, the increase of Pr in perovskite films is mainly an effort in material physics. At present, commonplace improvement schemes, i.e., controlling material crystallinity, and post‐annealing by using a high‐temperature process, are normally used. However, a simpler and temporal strategy for Pr improvement is always unavailable to perovskite material researchers. In this study, an organic coating layer, low‐temperature, and vacuum‐free strategy is proposed to improve the Pr, directly increasing the Pr from 36 to 56 µC cm−2. Further study finds that the increased Pr originates from the suppression of the oxygen defects and Ti defects. This organic coating layer strategy for passivating the defects may open a new way for the preparation of higher‐performance and cost‐effective perovskite products, further improving its prospective for application in the electron devices field. [ABSTRACT FROM AUTHOR]

Abstract: LaO- and NiO2-terminated LaNiO3 (001) surfaces were investigated by first principle calculations. For NiO2-terminated surface, Ni atoms exhibit an abnormal relaxation. Larger surface rumpling emerges in the topmost layer of LaO termination, which is almost twice as large as that of NiO2 termination. LaO-terminated surface has the lowest surface energy and stable structure. Non-polar surfaces exhibit remarkably different electronic structures and more Ni atoms exposed to the surface will contribute to higher density of states at Fermi level, which provides a guide to grow novel ultra-thin heterostructures with controlled electronic state of metal ions. [Copyright &y& Elsevier]