In-situ Observation of Trapped Carriers in Organic Metal Halide Perovskite Films with Ultra-Fast Temporal and Ultra-High Energetic Resolutions

Kanishka Kobbekaduwa, Shreetu Shrestha, Pan Adhikari, Exian Liu, Lawrence Coleman, Jianbing Zhang, Ying Shi, Yuanyuan Zhou, Yehonadav Bekenstein, Feng Yan, Apparao Rao, Hsinhan Tsai, Matthew Beard, Wanyi Nie, Jianbo Gao

Research output: Contribution to journalArticlepeer-review

12 Scopus Citations

Abstract

We in-situ observe the ultrafast dynamics of trapped carriers in organic methyl ammonium lead halide perovskite thin films by ultrafast photocurrent spectroscopy with a sub-25 picosecond time resolution. Upon ultrafast laser excitation, trapped carriers follow a phonon assisted tunneling mechanism and a hopping transport mechanism along ultra-shallow to shallow trap states ranging from 1.72–11.51 millielectronvolts and is demonstrated by time-dependent and independent activation energies. Using temperature as an energetic ruler, we map trap states with ultra-high energy resolution down to < 0.01 millielectronvolt. In addition to carrier mobility of ~4 cm2V−1s−1 and lifetime of ~1 nanosecond, we validate the above transport mechanisms by highlighting trap state dynamics, including trapping rates, de-trapping rates and trap properties, such as trap density, trap levels, and capture-cross sections. In this work we establish a foundation for trap dynamics in high defect-tolerant perovskites with ultra-fast temporal and ultra-high energetic resolution.

Original languageAmerican English
Article numberArticle No. 1636
Number of pages7
JournalNature Communications
Volume12
Issue number1
DOIs
StatePublished - 1 Dec 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).

NREL Publication Number

  • NREL/JA-5900-78753

Keywords

  • electronic properties and materials
  • metal-halide perovskite
  • semiconductors
  • solar cells
  • thin films
  • transport

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