The difference in electronic structure of MAPI and MASI perovskites and its effect on the interface alignment to the HTMs spiro-MeOTAD and CuI

Abstract

We have studied the electronic structure of CH3NH3PbI3 (MAPI) and CH3NH3SnI3 (MASI) perovskite films by performing X-ray photoelectron spectroscopy (XPS) measurements on in situ grown perovskite films.

The Electronic Structure of MAPI‐Based Perovskite Solar Cells: Detailed Band Diagram Determination by Photoemission Spectroscopy Comparing Classical and Inverted Device Stacks

“…Therefore, the full photovoltage of the classical architecture device has been identified at the back contact (n‐MAPI/p‐spiro‐MeOTAD/Au), which was already predicted in an earlier study, where the energy band diagram between MAPI and spiro‐MeOTAD was investigated. [ 48 ] It is concluded that the classical architecture is an n + ‐SnO 2 /n‐MAPI/p‐spiro‐MeOTAD structure and not an n‐SnO 2 /i‐MAPI/p‐spiro‐MeOTAD structure as it is often referred to in literature. [ 15–17,19 ] In case of an n‐i‐p structure, the photovoltage would be split up between the SnO 2 /MAPI and the MAPI/spiro‐MeOTAD interface.…”

“…With the VBM of SnO 2 ( = 3.85 eV, see Figure S8a, Supporting Information) and MAPI (VBM MAPI = 1.35 eV, see Figure 2c), an offset of 2.32 eV between the VBM of MAPI and SnO 2 results (Δ E VB ), demonstrating an efficient blocking of holes. With the bandgaps of SnO 2 ( = 3.60 eV) [ 49 ] and MAPI ( E g,MAPI = 1.58 eV), [ 48 ] the CBM of SnO 2 is positioned below the CBM of MAPI, which will allow electrons to be extracted from MAPI into the SnO 2 layer. Given the SPV of 0.80 eV at the MAPI/spiro‐MeOTAD interface, it is concluded that a built‐in potential of at least 0.80 eV exists at this interface for the dark case.…”

Revealing the Band Structure of FAPI Quantum Dot Film and Its Interfaces with Electron and Hole Transport Layer Using Time Resolved Photoemission

“…In addition, the performance of devices based on lead halide perovskite is strongly driven by the design of interfaces. [22][23][24] . Here we combine photoemission and (photo)transport measurement to demonstrate that the Fermi level of this material is located deeply within the band gap and that trap plays a limited role on charge recombination.…”

Preparation of Methylammonium Tin Iodide (CH3NH3SnI3) Perovskite Thin Films via Flash Evaporation

“…The measurement shows that MASI, produced by this method, is a p‐type material with valence band maximum (VBM) ‐ E F of 0.4 eV, having a bandgap of 1.3 eV (Figure ). Using a work function Φ of 4.75 eV for ultra‐high vacuum (UHV) deposited MASI, a band diagram can be drawn as displayed in Figure , which may be used for the first selection of appropriate hole and electron extraction layers according to the simple vacuum level alignment.…”

“…III (Figure ); Right, concluded band diagram. The value of the bandgap E g is taken from our UV–vis measurement Figure and for the work function Φ, marked with an asterisk (*), from our measurement …”