Role of surface recombination in halide perovskite nanoplatelets

Xiaoming Wen, Weijian Chen, Jianfeng Yang, Qingdong Ou, Tieshan Yang, Chunhua Zhou, Han Lin, Ziyu Wang, Yupeng Zhang, Gavin Conibeer, Qiaoliang Bao, Baohua Jia, David J. Moss

Research output: Contribution to journalArticleResearchpeer-review

20 Citations (Scopus)

Abstract

Halide perovskites are an extremely promising material platform for solar cells and photonic devices. The role of surface carrier recombination - well known to detrimentally affect the performance of devices - is still not well understood for thin samples where the thickness is comparable to or less than the carrier diffusion length. Here, using time-resolved microspectroscopy along with modeling, we investigate charge-carrier recombination dynamics in halide perovskite CH3NH3PbI3 nanoplatelets with thicknesses from 20 to 200 nm, ranging from much lesser than to comparable to the carrier diffusion length. We show that surface recombination plays a stronger role in thin perovskite nanoplatelets, significantly decreasing photoluminescence (PL) efficiency, PL decay lifetime, and photostability. Interestingly, we find that both thick and thin nanoplatelets exhibit a similar increase in PL efficiency with increasing excitation fluence, well described by our excitation saturation model. We also find that the excited carrier distribution along the depth impacts the surface recombination. Using the diffusion-surface recombination model, we determine the surface recombination velocity. This work provides a comprehensive understanding of the role of surface recombination and charge-carrier dynamics in thin perovskite platelets and reveals valuable insights useful for applications in photovoltaics and photonics.

Original languageEnglish
Pages (from-to)31586-31593
Number of pages8
JournalACS Applied Materials & Interfaces
Volume10
Issue number37
DOIs
Publication statusPublished - 19 Sep 2018

Keywords

  • charge-carrier recombination
  • modeling
  • perovskite nanoplatelet
  • surface recombination
  • time-resolved photoluminescence

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