We report here the discovery of a fancy interaction between cesium iodide (CsI) and methylamine (CH3NH2) due to the presence of the hydrogen bond. The formed CsI·xCH3NH2 is a liquid phase, which facilitates the large scale fabrication of highly uniform cesium-containing perovskite films with strong (110) preferred orientation by the CH3NH2 gas healing process. With this method, at most 10% nonpolar Cs cations could fully dope into the crystal lattice and extremely enhance the interaction of the inorganic framework with a more symmetrical PbI6 octahedron, resulting in obvious improvement in moisture stability under continuous illumination.
Bibliographical noteFunding Information:
This work was financially supported by the International S&T Cooperation Program of China (2015DFG62670), the National Natural Science Foundation (51672290, 21671196, and 61604156), the Youth Innovation Promotion Association of CAS (2015167), and the Qingdao Key Lab of solar energy utilization and energy storage technology.
© The Royal Society of Chemistry.