Origin of Low Temperature Trion Emission in CdSe Nanoplatelets

Albert F. Vong, Shawn Irgen-Gioro, Yue Wu, Emily A. Weiss*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Colloidal semiconductor nanoplatelets (NPLs) are a scalable materials platform for optoelectronic applications requiring fast and narrow emission, including spin-to-photon transduction within quantum information networks. In particular, three-particle negative trions of NPLs are appealing emitters since, unlike excitons, they do not have an optically “dark” sublevel. In CdSe NPLs, trion emission dominates the photoluminescence (PL) spectrum at low temperature but using them as single photon-emitting states requires more knowledge about their preparation, since trions in these materials are not directly optically accessible from the ground state. This work demonstrates, using power-dependent time-resolved transient absorptions (TA) of CdSe NPLs, that trions form via biexciton decay in 1.6 ps. The scaling of the trion population and formation lifetime with excitation power indicates that they do not form through collisional mechanisms typical for 2D materials, but rather by a unimolecular hole transfer. This work is a step toward deterministic single photon emission from trions.

Original languageEnglish (US)
Pages (from-to)10040-10046
Number of pages7
JournalNano letters
Volume21
Issue number23
DOIs
StatePublished - Dec 8 2021

Keywords

  • biexciton
  • charged exciton
  • colloidal quantum wells
  • hole transfer
  • nanocrystals
  • transient absorption

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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