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Title: Coexistence of two electronic nano-phases on a CH 3NH 3PbI 3–xCl x surface observed in STM measurements

Scanning tunneling microscopy is utilized to investigate the local density of states of a CH 3NH 3PbI 3-xCl x perovskite in cross-sectional geometry. Two electronic phases, 10-20 nm in size, with different electronic properties inside the CH 3NH 3PbI 3-xCl x perovskite layer are observed by the dI/ dV mapping and point spectra. A power law dependence of the dI/dV point spectra is revealed. In addition, the distinct electronic phases are found to have preferential orientations close to the normal direction of the film surface. Density functional theory calculations indicate that the observed electronic phases are associated with local deviation of I/Cl ratio, rather than different orientations of the electric dipole moments in the ferroelectric phases. Furthermore, by comparing the calculated results with experimental data we conclude that phase A (lower contrast in dI/dV mapping at -2.0 V bias) contains a lower I/Cl ratio than that in phase B (higher contrast in dI/dV).
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [1] ;  [1]
  1. Univ. of Wyoming, Laramie, WY (United States)
  2. National Taiwan Univ., Taipei (Taiwan); Argonne National Lab. (ANL), Lemont, IL (United States)
  3. Argonne National Lab. (ANL), Lemont, IL (United States); Univ. of Chicago, Chicago, IL (United States)
  4. National Taiwan Univ., Taipei (Taiwan)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 8; Journal Issue: 42; Journal ID: ISSN 1944-8244
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
36 MATERIALS SCIENCE; organometallic halide perovskite; cross-sectional scanning tunneling microscopy; density functional theory; electronic phase; mixed halide; nano-phase
OSTI Identifier: