1 Supporting Information for: Termination Dependence of Tetragonal CH 3 NH 3 PbI 3 Surfaces for Perovskite Solar Cells Jun Haruyama, †,‡ Keitaro Sodeyama, †,§ Liyuan Han, ∥,⊥ and Yoshitaka Tateyama *,†,§, ⊥ †International Center for Materials Nanoarchitectonics (WPI-MANA) and ‡Global Research Center for Environmental and Energy Nanoscience (GREEN), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan §Elements strategy Initiative for Catalysts and Batteries, Kyoto University, Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan ∥Photovoltaic Materials Unit, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan ⊥PRESTO and CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 333-0012, Japan Corresponding Author *[email protected]
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Supporting Information for:
Termination Dependence of Tetragonal CH3NH3PbI3
Surfaces for Perovskite Solar Cells
Jun Haruyama,†,‡ Keitaro Sodeyama,†,§ Liyuan Han,∥,⊥ and Yoshitaka Tateyama*,†,§,⊥
†International Center for Materials Nanoarchitectonics (WPI-MANA) and ‡Global Research Center for Environmental and Energy Nanoscience (GREEN), National Institute
for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
§Elements strategy Initiative for Catalysts and Batteries, Kyoto University, Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan
∥Photovoltaic Materials Unit, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
⊥PRESTO and CREST, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 333-0012, Japan
DFT calculations of the MAPbI3 bulk crystal were carried out with the tetragonal and orthorhombic phases.
Figure S1 shows the adopted simulation cells with the four units of MAPbI3 including 48 atoms for both
phases. The k-point sampling utilized a 4×4×4 k-point mesh. For the tetragonal phase, the initial atomic
positions of Pb and I as well as the cell parameters were set to the Kawamura’s data,S1 and MA molecules
were placed referring to the Mosconi’s configurations.S2 For the orthorhombic phase, the Baikie’s crystal
dataS3 were used for the initial atomic positions and cell parameters. The atomic positions and the cell
parameters were relaxed until the residual forces and stresses became less than 0.001 Ry/bohr and 0.5 kbar,
respectively. Table S1 gives the lattice constants and energy gaps obtained in our calculations, with the
experimental values. Our results are in good agreement with experiments and previous DFT calculations.S1-S6
Figure S2 shows PDOSs of the tetragonal and orthorhombic phases, where the cell parameters are set to the
experimental values and PBE functional is used.
Figure S1. The unit cells used for the bulk crystal calculations: (a) tetragonal and (b) orthorhombic phases of
MAPbI3. The [001] ([110]) direction of the tetragonal and the [010] ([101]) of the orthorhombic phases
correspond to the [001] ([100]) of the perovskite structure.
(b)
a
b
c
a
(a)
a
b
b
c
3
Table S1. The cell parameters and the energy gaps of the bulk crystals of MAPbI3 in the present calculations
in comparison with the experimental data.
a [Å] b [Å] c [Å] Eg [eV]
tetragonal PBE 8.863 8.997 12.989 1.68 a, 1.64 b
rev-vdW-DF 8.819 8.809 12.846 1.59 a
experimentS1 8.8009 8.8009 12.6857 1.51S3, 1.57S4
orthorhombic PBE 9.196 12.855 8.620 1.80a, 1.70b
rev-vdW-DF 8.881 12.720 8.604 1.79 a
experimentS3 8.8362 12.5804 8.5551 1.68S5 a Calculated value with relaxed cell parameters. b Calculated value with cell parameters fixed at the experimental values.
Figure S2. PDOSs of (a) tetragonal and (b) orthorhombic phases of the MAPbI3 bulk crystal. Black, green,
red, orange, and blue lines represent PDOSs of total, I 5s, I 5p, Pb 6s, Pb 6p, respectively. The tops of the
valence bands are set to the energy origin.
(b) orthorhombic
-2 -1 0 1 2Energy [eV]
Den
sity
of s
tate
s
0
TotalI 5sI 5pPb 6sPb 6p
TotalI 5sI 5pPb 6sPb 6p
-3 3
(a) tetragonal
-2 -1 0 1 2Energy [eV]
Den
sity
of s
tate
s
0-3 3
4
S2. Surface Terminations
The surface calculations were carried out with the surface slabs of the (110), (001), (100), and (101) faces
with 1×4×4, 4×6×1, 1×6×4, and 1×6×4 k-point meshes, respectively. Figure S3 shows the initial surface
structures. The cell parameters, the termination labels, the stoichiometric ratios, and the atom numbers of each
MAPbI3 surface slab are summarized in Table S2.
Figure S3. Initial surface structures of tetragonal MAPbI3: (a) (110), (b) (001), (c) (100), and (d) (101).
