title: Valence and Conduction Band Densities of States of Metal Halide Perovskites: A Combined Experimental-Theoretical Study.
abstract: We report valence and conduction band densities of states measured via ultraviolet and inverse photoemission spectroscopies on three metal halide perovskites, specifically methylammonium lead iodide and bromide and cesium lead bromide (MAPbI3, MAPbBr3, CsPbBr3), grown at two different institutions on different substrates. These are compared with theoretical densities of states (DOS) calculated via density functional theory. The qualitative agreement achieved between experiment and theory leads to the identification of valence and conduction band spectral features, and allows a precise determination of the position of the band edges, ionization energy and electron affinity of the materials. The comparison reveals an unusually low DOS at the valence band maximum (VBM) of these compounds, which confirms and generalizes previous predictions of strong band dispersion and low DOS at the MAPbI3 VBM. This low DOS calls for special attention when using electron spectroscopy to determine the frontier electronic states of lead halide perovskites.
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: James
authors.initials: J
authors.lastname: Endres
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth, 76100, Israel.
authors.forename: David A
authors.initials: DA
authors.lastname: Egger
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth, 76100, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Kulbak
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Kerner
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Lianfeng
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Scott H
authors.initials: SH
authors.lastname: Silver
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth, 76100, Israel.
authors.forename: Gary
authors.initials: G
authors.lastname: Hodes
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Barry P
authors.initials: BP
authors.lastname: Rand
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth, 76100, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Cahen
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth, 76100, Israel.
authors.forename: Leeor
authors.initials: L
authors.lastname: Kronik
authors.affiliation: Department of Electrical Engineering, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Antoine
authors.initials: A
authors.lastname: Kahn