Surface analytical investigation on organometal triiodide perovskite
- Univ. of Rochester, Rochester, NY (United States)
- Central South Univ., Hunan (People's Republic of China)
- Univ. of Nebraska, Lincoln, NE (United States)
In a little over a year, there has been an unexpected breakthrough and rapid evolution of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite materials. This technology has the potential to produce solar cells with the very highest efficiencies while retaining the very lowest cost. The authors have measured the electronic density of states of CH3NH3PbI3 using ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and x-ray photoemission spectroscopy(XPS). The valence band maximum and conduction band minimum positions are obtained from the UPS and IPES spectra, respectively, by linear extrapolation of the leading edges. The authors investigate the Au/perovskite and C60/perovskite interfaces by UPS and XPS. An interface dipole of 0.1 eV is observed at Au/perovskite interface. The energy levels of perovskite shift upward by ca.0.4 eV with Au coverage of 64 Å upon it, resulting in band bending, hence a built-in field in perovskite that encourages hole transport to the interface. The XPS results show a strong initial shift of core levels to lower binding energy in the perovskite, which indicates that electrons transfer from the perovskitefilm to fullerene molecules. Further deposition of fullerene forms C60 solid, accompanied by the reduction of the electron transfer. As a result, the strongest electron transfer happened at 1/4 monolayer of fullerene.
- Research Organization:
- Univ. of Nebraska, Lincoln, NE (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- EE0006709; Contract No. DE-AC02-98CH1-886
- OSTI ID:
- 1238031
- Alternate ID(s):
- OSTI ID: 1420581
- Journal Information:
- Journal of Vacuum Science and Technology B, Vol. 33, Issue 3; ISSN 2166-2746
- Publisher:
- American Vacuum Society / AIPCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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