Colloidal synthesis of ternary copper indium diselenide quantum dots and their optical properties

Katsuhiro Nose, Takahisa Omata, Otsuka Yao Matsuo Shinya

Research output: Contribution to journalArticlepeer-review

115 Citations (Scopus)

Abstract

Ternary direct semiconductor CuInSe2 quantum dots (QDs) with average particle sizes ranging from 1.2 to 5.6 nm have been synthesized by a colloidal route using commercially available materials. The size-dependent optical band gap and photoluminescence (PL) band shift due to the quantum size effect were successfully observed. The optical band gap evaluated from the optical absorption spectra was varied from 1.48 eV for the 5.6-nm QDs to 1.66 eV for the 1.2-nm QDs. In the PL spectra, the wavelength of the emission band varied from 918 to 838 nm corresponding to the crystal size variation from 5.6 to 1.2 nm. Because the PL band showed a large Stokes shift above 100 meV, the origin of the PL band was related to the electronic transition via defect levels. Based on the slightly In-rich composition of the QDs and the comparatively large increase in energy of the PL band with decreasing crystal size, the emission was suggested to be due to the recombination between electrons in the quantized conduction band and holes in the copper vacancy acceptor.

Original languageEnglish
Pages (from-to)3455-3460
Number of pages6
JournalJournal of Physical Chemistry C
Volume113
Issue number9
DOIs
Publication statusPublished - 2009 Mar 5
Externally publishedYes

ASJC Scopus subject areas

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

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