Thermally Activated Exciton Dissociation and Recombination Control the Carrier Dynamics in Organometal Halide Perovskite

Tom J. Savenije, Carlito Ponseca, Lucas Kunneman, Mohamed Qenawy, Kaibo Zheng, Yuxi Tian, Qiushi Zhu, Sophie Canton, Ivan Scheblykin, Tönu Pullerits, Arkady Yartsev, Villy Sundström

Research output: Contribution to journalArticlepeer-review

370 Citations (SciVal)

Abstract

Solar cells based on organometal halide perovskites have seen rapidly increasing efficiencies, now exceeding 15%. Despite this progress, there is still limited knowledge on the fundamental photophysics. Here we use microwave photoconductance and photoluminescence measurements to investigate the temperature dependence of the carrier generation, mobility, and recombination in (CH3NH3)PbI3. At temperatures maintaining the tetragonal crystal phase of the perovskite, we find an exciton binding energy of about 32 meV, leading to a temperature-dependent yield of highly mobile (6.2 cm(2)/(V s) at 300 K) charge carriers. At higher laser intensities, second-order recombination with a rate constant of gamma = 13 x 10(-10) cm(3) s(-1) becomes apparent. Reducing the temperature results in increasing charge carrier mobilities following a T-1.6 dependence, which we attribute to a reduction in phonon scattering (Sigma mu = 16 cm(2)/(V s) at 165 K). Despite the fact that Sigma mu increases, gamma diminishes with a factor six, implying that charge recombination in (CH3NH3)PbI3 is temperature activated. The results underline the importance of the perovskite crystal structure, the exciton binding energy, and the activation energy for recombination as key factors in optimizing new perovskite materials.
Original languageEnglish
Pages (from-to)2189-2194
JournalThe Journal of Physical Chemistry Letters
Volume5
Issue number13
DOIs
Publication statusPublished - 2014

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Max-laboratory (011012005), Chemical Physics (S) (011001060)

Subject classification (UKÄ)

  • Natural Sciences
  • Atom and Molecular Physics and Optics
  • Physical Sciences

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