Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties

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...

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Main Authors: Kaur, Manpreet, Sharma, Ashma, Olutas, Murat, Erdem, Onur, Kumar, Akshay, Sharma, Manoj, Demir, Hilmi Volkan
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2018
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Online Access:https://hdl.handle.net/10356/86304
http://hdl.handle.net/10220/45237
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-863042020-06-01T10:01:38Z Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties Kaur, Manpreet Sharma, Ashma Olutas, Murat Erdem, Onur Kumar, Akshay Sharma, Manoj Demir, Hilmi Volkan School of Electrical and Electronic Engineering School of Materials Science & Engineering School of Physical and Mathematical Sciences LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays Cadmium Free Colloidal Quantum Dots 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. Published version 2018-07-25T08:39:15Z 2019-12-06T16:20:03Z 2018-07-25T08:39:15Z 2019-12-06T16:20:03Z 2018 Journal Article Kaur, M., Sharma, A., Olutas, M., Erdem, O., Kumar, A., Sharma, M., et al. (2018). Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties. Nanoscale Research Letters, 13, 182-. 1931-7573 https://hdl.handle.net/10356/86304 http://hdl.handle.net/10220/45237 10.1186/s11671-018-2599-x en Nanoscale Research Letters © 2018 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. 11 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Cadmium Free
Colloidal Quantum Dots
spellingShingle Cadmium Free
Colloidal Quantum Dots
Kaur, Manpreet
Sharma, Ashma
Olutas, Murat
Erdem, Onur
Kumar, Akshay
Sharma, Manoj
Demir, Hilmi Volkan
Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties
description 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.
author2 School of Electrical and Electronic Engineering
author_facet School of Electrical and Electronic Engineering
Kaur, Manpreet
Sharma, Ashma
Olutas, Murat
Erdem, Onur
Kumar, Akshay
Sharma, Manoj
Demir, Hilmi Volkan
format Article
author Kaur, Manpreet
Sharma, Ashma
Olutas, Murat
Erdem, Onur
Kumar, Akshay
Sharma, Manoj
Demir, Hilmi Volkan
author_sort Kaur, Manpreet
title Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties
title_short Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties
title_full Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties
title_fullStr Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties
title_full_unstemmed Cd-free Cu-doped ZnInS/ZnS core/shell nanocrystals : controlled synthesis and photophysical properties
title_sort cd-free cu-doped znins/zns core/shell nanocrystals : controlled synthesis and photophysical properties
publishDate 2018
url https://hdl.handle.net/10356/86304
http://hdl.handle.net/10220/45237
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