High Excitation Intensity Opens a New Trapping Channel in Organic-Inorganic Hybrid Perovskite Nanoparticles

Kaibo Zheng, Karel Žídek, Mohamed Abdellah, Junsheng Chen, Pavel Chábera, Wei Zhang, Jaber Al Marri, Tõnu Pullerits

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

We investigated the excited-state dynamics of CH3NH3PbBr3 perovskite nanoparticles (NPs) and bulk crystals under various excitation intensity regimes using transient absorption spectroscopy. We confirmed the sub-band gap hole trap states with optical transition to the conduction band in both samples. In bulk crystals, the excited-state dynamics is independent of pump intensity. However, in NPs, pronounced intensity dependence appears. At low intensities, the hole trap states do not affect the excited-state dynamics due to the potential barrier between the photogenerated holes and the surface trap states. When the excitation density is much higher than one per NP, charge accumulation makes hot holes overcome the barrier and get trapped with electrons long living in the conduction band (≥10 ns). This explains the high emissive properties of such NPs despite the existence of surface traps. However, in the application of emitting devices requiring high excitation intensity, the surface trapping becomes significant.

Original languageEnglish
Pages (from-to)1154-1161
Number of pages8
JournalACS Energy Letters
Volume1
Issue number6
DOIs
Publication statusPublished - 9 Dec 2016
Externally publishedYes

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ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Energy Engineering and Power Technology
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment
  • Materials Chemistry

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