Linking Chemistry at the TiO2/CH3NH3PbI3 Interface to Current-Voltage Hysteresis

Ross A. Kerner, Barry P. Rand

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

We demonstrate that reversible chemical reactions occur at TiO2/gas and CH3NH3PbI3/gas interfaces on a time scale of seconds to minutes. The chemisorption strongly affects their electronic properties, mainly acting to deplete TiO2 of free electrons and passivate surface traps on the perovskite. Although the chemistry is not directly probed, we infer that reversible chemistry occurs at the solid-state TiO2/CH3NH3PbI3 interface. Equilibrium or steady-state concentrations established for adsorbed species associated with each material would be voltage- and illumination-dependent due to free or photocarriers being a main reactant. Interfacial chemistry provides an additional physical mechanism to explain the origins of normal and anomalous hysteretic current-voltage characteristics of perovskite devices. Furthermore, chemical reactions help us to understand why measured perovskite ion-transport properties and the nature of hysteresis are highly dependent on interfaces.

Original languageEnglish (US)
Pages (from-to)2298-2303
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume8
Issue number10
DOIs
StatePublished - May 18 2017

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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