Interfacial electronic structure at the CH{sub 3}NH{sub 3}PbI{sub 3}/MoO{sub x} interface
- Institute of Super-Microstructure and Ultrafast Process in Advanced Materials, College of Physics and Electronics, Central South University, Changsha 410083 (China)
- Department of Mechanical and Materials Engineering and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0656 (United States)
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States)
Interfacial electronic properties of the CH{sub 3}NH{sub 3}PbI{sub 3} (MAPbI{sub 3})/MoO{sub x} interface are investigated using ultraviolet photoemission spectroscopy and X-ray photoemission spectroscopy. It is found that the pristine MAPbI{sub 3} film coated onto the substrate of poly (3,4-ethylenedioxythiophene) poly(styrenesulfonate)/indium tin oxide by two-step method behaves as an n-type semiconductor, with a band gap of ∼1.7 eV and a valence band edge of 1.40 eV below the Fermi energy (E{sub F}). With the MoO{sub x} deposition of 64 Å upon MAPbI{sub 3}, the energy levels of MAPbI{sub 3} shift toward higher binding energy by 0.25 eV due to electron transfer from MAPbI{sub 3} to MoO{sub x}. Its conduction band edge is observed to almost pin to the E{sub F}, indicating a significant enhancement of conductivity. Meanwhile, the energy levels of MoO{sub x} shift toward lower binding energy by ∼0.30 eV, and an interface dipole of 2.13 eV is observed at the interface of MAPbI{sub 3}/MoO{sub x}. Most importantly, the chemical reaction taking place at this interface results in unfavorable interface energy level alignment for hole extraction. A potential barrier of ∼1.36 eV observed for hole transport will impede the hole extraction from MAPbI{sub 3} to MoO{sub x}. On the other hand, a potential barrier of ∼0.14 eV for electron extraction is too small to efficiently suppress electrons extracted from MAPbI{sub 3} to MoO{sub x}. Therefore, such an interface is not an ideal choice for hole extraction in organic photovoltaic devices.
- OSTI ID:
- 22399068
- Journal Information:
- Applied Physics Letters, Vol. 106, Issue 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BINDING ENERGY
DEPOSITION
ELECTRON TRANSFER
ELECTRONIC STRUCTURE
ELECTRONS
EMISSION SPECTROSCOPY
ENERGY LEVELS
FILMS
HOLES
INTERFACES
N-TYPE CONDUCTORS
PHOTOELECTRON SPECTROSCOPY
PHOTOVOLTAIC EFFECT
POTENTIALS
SUBSTRATES
TIN OXIDES
ULTRAVIOLET RADIATION
VALENCE
X-RAY SPECTROSCOPY