Photophysics of Organic-Inorganic Hybrid Lead Iodide Perovskite Single Crystals

Honghua Fang, Raissa Raissa, Mustapha Abdu-Aguye, Sampson Adjokatse, Graeme R. Blake, Jacky Even, Maria Antonietta Loi

Research output: Contribution to journalArticleAcademicpeer-review

249 Citations (Scopus)

Abstract

Hybrid organometal halide perovskites have been demonstrated to have outstanding performance as semiconductors for solar energy conversion. Further improvement of the efficiency and stability of these devices requires a deeper understanding of their intrinsic photophysical properties. Here, the structural and optical properties of high-quality single crystals of CH3NH3PbI3 from room temperature to 5 K are investigated. X-ray diffraction reveals an extremely sharp transition at 163 K from a twinned tetragonal I4/mcm phase to a low-temperature phase characterized by complex twinning and possible frozen disorder. Above the transition temperature, the photoluminescence is in agreement with a band-edge transition, explaining the outstanding performances of the solar cells. Whereas below the transition temperature, three different excitonic features arise, one of which is attributed to a free-exciton and the other two to bound excitons (BEs). The BEs are characterized by a decay dynamics of about 5 mu s and by a saturation phenomenon at high power excitation. The long lifetime and the saturation effect make us attribute these low temperature features to bound triplet excitons. This results in a description of the room temperature recombination as being due to spontaneous band-to-band radiative transitions, whereas a diffusion-limited behavior is expected for the low-temperature range.

Original languageEnglish
Pages (from-to)2378-2385
Number of pages8
JournalAdvanced Functional Materials
Volume25
Issue number16
DOIs
Publication statusPublished - 22-Apr-2015

Keywords

  • ORGANOMETAL HALIDE PEROVSKITES
  • BAND-EDGE PHOTOLUMINESCENCE
  • SOLAR-CELL APPLICATIONS
  • OPTICAL-PROPERTIES
  • EXCITON
  • CH3NH3PBI3
  • SEMICONDUCTORS
  • TRANSITIONS
  • MOBILITIES
  • DEPOSITION

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