Substrate-Dependent Photoconductivity Dynamics in a High-Efficiency Hybrid Perovskite Alloy

David Moore, Jeffrey Christians, Ali Tirmzi, Ryan Dwyer, John Marohn

Research output: Contribution to journalArticlepeer-review

9 Scopus Citations


Films of (FA 0.79 MA 0.16 Cs 0.05 ) 0.97 Pb(I 0.84 Br 0.16 ) 2.97 were grown over TiO 2 , SnO 2 , indium tin oxide (ITO), and NiO. Film conductivity was interrogated by measuring the in-phase and out-of-phase forces acting between the film and a charged microcantilever. We followed the films' conductivity versus time, frequency, light intensity, and temperature (233-312 K). Perovskite conductivity was high and light-independent over ITO and NiO. Over TiO 2 and SnO 2 , the conductivity was low in the dark, increased with light intensity, and persisted for 10's of seconds after the light was removed. At an elevated temperature over TiO 2 , the rate of conductivity recovery in the dark showed an activated temperature dependence (E a = 0.58 eV). Surprisingly, the light-induced conductivity over TiO 2 and SnO 2 relaxed essentially instantaneously at a low temperature. We use a transmission-line model for mixed ionic-electronic conductors to show that the measurements presented are sensitive to the sum of electronic and ionic conductivities. We rationalize the seemingly incongruous observations using the idea that holes, introduced either by equilibration with the substrate or via optical irradiation, create iodide vacancies.

Original languageAmerican English
Pages (from-to)3402-3415
Number of pages14
JournalJournal of Physical Chemistry C
Issue number6
StatePublished - 14 Feb 2019

Bibliographical note

Publisher Copyright:
© 2019 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-73256


  • conductivity
  • perovskites
  • photoconductivity
  • thin films


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