Cd-free Cu-doped ZnInS/ZnS Core/Shell nanocrystals: Controlled synthesis and photophysical properties

Date
2018
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
Nanoscale Research Letters
Print ISSN
1931-7573
Electronic ISSN
1556-276X
Publisher
SpringerOpen
Volume
13
Issue
Pages
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Series
Abstract

Here, we report efficient composition-tunable Cu-doped ZnInS/ZnS (core and core/shell) colloidal nanocrystals (CNCs) synthesized by using a colloidal non-injection method. The initial precursors for the synthesis were used in oleate form rather than in powder form, resulting in a nearly defect-free photoluminescence (PL) emission. The change in Zn/In ratio tunes the percentage incorporation of Cu in CNCs. These highly monodisperse Cu-doped ZnInS CNCs having variable Zn/In ratios possess peak emission wavelength tunable from 550 to 650 nm in the visible spectrum. The quantum yield (QY) of these synthesized Cd-free CNCs increases from 6.0 to 65.0% after coating with a ZnS shell. The CNCs possessing emission from a mixed contribution of deep trap and dopant states to only dominant dopant-related Stokes-shifted emission are realized by a careful control of stoichiometric ratio of different reactant precursors during synthesis. The origin of this shift in emission was understood by using steady state and time-resolved fluorescence (TRF) spectroscopy studies. As a proof-of-concept demonstration, these blue excitable Cu-doped ZnInS/ZnS CNCs have been integrated with commercial blue LEDs to generate white-light emission (WLE). The suitable combination of these highly efficient doped CNCs results led to a Commission Internationale de l’Enclairage (CIE) color coordinates of (0.33, 0.31) at a color coordinate temperature (CCT) of 3694 K, with a luminous efficacy of optical radiation (LER) of 170 lm/Wopt and a color rendering index (CRI) of 88.

Course
Other identifiers
Book Title
Keywords
Cadmium free, Colloidal quantum dots, Color properties, Quantum yield, Cu doping, White-light emission, Color properties
Citation
Published Version (Please cite this version)