Trap States and Their Dynamics in Organometal Halide Perovskite Nanoparticles and Bulk Crystals

Kaibo Zheng, Karel Žídek, Mohamed Abdellah, Maria E. Messing, Jaber Al Marri, Tõnu Pullerits

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Organometal halide perovskites have attracted tremendous attention for optoelectronic applications. Charge carrier trapping is one of the dominant processes often deteriorating the performance of devices. Here, we investigate the details of trap behavior in colloidal nanoparticles (NPs) of CH3NH3PbBr3 perovskites with mean size of 8 nm and the corresponding bulk crystals (BCs). We use excitation intensity dependence of photoluminescence (PL) dynamics together with comprehensive simulation of charge carrier trapping and the trap-state dynamics. In the bulk at very low excitation intensities the PL is quenched by trapping. A considerable fraction of the traps become filled if excitation fluence is increased. We identified two different traps, one exhibiting ultralong lifetime (∼70 μs) which leads to efficient accumulation of trap filling even at relatively low excitation intensities. In colloidal NPs, the average number of surface traps is estimated to be 0.7 per NP. It means about 30% excitation would undergo trap-free radiative recombination. The trapping time constant of 7 ns is orders of magnitude longer than the usual trapping times in typical colloidal quantum dots indicating semipassivation of the trap states by a large barrier which slows down the process in the perovskite NPs. We also note that due to the localized character of photogenerated electron-hole pairs in NPs the trapping efficiency is reduced compared to the freely moving charges in BCs. Our results offer insight into the details of photophysics of colloidal perovskite nanoparticles which show promise for light-emitting diode and laser applications.

Original languageEnglish
Pages (from-to)3077-3084
Number of pages8
JournalJournal of Physical Chemistry C
Volume120
Issue number5
DOIs
Publication statusPublished - 18 Feb 2016
Externally publishedYes

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Perovskite
halides
traps
Nanoparticles
nanoparticles
Crystals
trapping
crystals
Charge carriers
excitation
Photoluminescence
perovskites
charge carriers
Laser applications
photoluminescence
Optoelectronic devices
Semiconductor quantum dots
Light emitting diodes
perovskite
laser applications

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Cite this

Trap States and Their Dynamics in Organometal Halide Perovskite Nanoparticles and Bulk Crystals. / Zheng, Kaibo; Žídek, Karel; Abdellah, Mohamed; Messing, Maria E.; Al Marri, Jaber; Pullerits, Tõnu.

In: Journal of Physical Chemistry C, Vol. 120, No. 5, 18.02.2016, p. 3077-3084.

Research output: Contribution to journalArticle

Zheng, Kaibo ; Žídek, Karel ; Abdellah, Mohamed ; Messing, Maria E. ; Al Marri, Jaber ; Pullerits, Tõnu. / Trap States and Their Dynamics in Organometal Halide Perovskite Nanoparticles and Bulk Crystals. In: Journal of Physical Chemistry C. 2016 ; Vol. 120, No. 5. pp. 3077-3084.
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