title: The nature of hydrogen-bonding interaction in the prototypic hybrid halide perovskite, tetragonal CH3NH3PbI3.
abstract: In spite of the key role of hydrogen bonding in the structural stabilization of the prototypic hybrid halide perovskite, CH3NH3PbI3 (MAPbI3), little progress has been made in our in-depth understanding of the hydrogen-bonding interaction between the MA(+)-ion and the iodide ions in the PbI6-octahedron network. Herein, we show that there exist two distinct types of the hydrogen-bonding interaction, naming α- and β-modes, in the tetragonal MAPbI3 on the basis of symmetry argument and density-functional theory calculations. The computed Kohn-Sham (K-S) energy difference between these two interaction modes is 45.14 meV per MA-site with the α-interaction mode being responsible for the stable hydrogen-bonding network. The computed bandgap (Eg) is also affected by the hydrogen-bonding mode, with Eg of the α-interaction mode (1.73 eV) being significantly narrower than that of the β-interaction mode (2.03 eV). We have further estimated the individual bonding strength for the ten relevant hydrogen bonds having a bond critical point.
authors.affiliation: Department of Materials Science and Engineering, and Division of Advanced Materials Science (AMS), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: June Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, and Division of Advanced Materials Science (AMS), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: Jung-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Korea Atomic Energy Research Institute (KAERI), Yuseong-Gu, Daejeon 305-353, Republic of Korea.
authors.forename: Eui-Hyun
authors.initials: EH
authors.lastname: Kong
authors.affiliation: Department of Materials Science and Engineering, and Division of Advanced Materials Science (AMS), Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
authors.forename: Hyun Myung
authors.initials: HM
authors.lastname: Jang