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Title: Vapor Deposition of Perovskite Precursor PbI 2 on Au and Graphite
Abstract The energy level alignment that occurs at the interfaces in planar-hetero structured perovskite photovoltaic devices strongly influences the charge transport across the interface, and thus plays a crucial role in overall device performance. To directly observe the energy level alignment requires pristine homogeneous surfaces that are free of contamination including adventitious carbon. Co-evaporation offers the ability to grow perovskite thin films in-situ, and the method involves thermally evaporating the perovskite precursors such as PbI 2 and CH 3 NH 3 I. Early reports have shown that the perovskite film formation and stoichiometry are problematic at ultralow coverages. In particular, it was reported that there was excessive PbI 2 and a deficiency in CH 3 NH 3 I. Using photoemission spectroscopy, we investigated the perovskite precursor PbI 2 on gold and highly oriented pyrolytic graphite (HOPG) surfaces. Results show that the nature of the surface and the deposition conditions can strongly influence the film formation. Excessive iodine observed in the initial evaporation stages appears to be substrate dependent, and this may influence the overall energy level alignment.  more » « less
Award ID(s):
1903962
PAR ID:
10149488
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
MRS Advances
Volume:
5
Issue:
8-9
ISSN:
2059-8521
Page Range / eLocation ID:
403 to 410
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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