Charge Transport and Recombination in Perovskite (CH3NH3)PbI3 Sensitized TiO2 Solar Cells

Yixin Zhao, Kai Zhu

Research output: Contribution to journalArticlepeer-review

298 Scopus Citations

Abstract

We report on the effect of TiO2 film thickness on the charge transport, recombination, and device characteristics of perovskite (CH 3NH3)PbI3 sensitized solar cells using iodide-based electrolytes. (CH3NH3)PbI3 is relatively stable in a nonpolar solvent (e.g., ethyl acetate) with a low iodide concentration (e.g., 80 mM). Frequency-resolved modulated photocurrent/ photovoltage spectroscopies show that increasing TiO2 film thickness from 1.8 to 8.3 μm has little effect on transport but increases recombination by more than 10-fold, reducing the electron diffusion length from 16.9 to 5.5 μm, which can be explained by the higher degree of iodide depletion within the TiO2 pores for thicker films. The changes of the charge-collection and light-absorption properties of (CH3NH 3)PbI3 sensitized cells with varying TiO2 film thickness strongly affect the photocurrent density, photovoltage, fill factor, and solar conversion efficiency. Developing alternative, compatible redox electrolytes is important for (CH3NH3)PbI3 or similar perovskites to be used for potential photoelectrochemical applications.

Original languageAmerican English
Pages (from-to)2880-2884
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume4
Issue number17
DOIs
StatePublished - 5 Sep 2013

NREL Publication Number

  • NREL/JA-5900-60105

Keywords

  • dye-sensitized solar cells
  • perovskite
  • recombination
  • thickness dependence
  • transport

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