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Space charge behavior of quantum dot-doped polystyrene polymers

Space charge behavior of quantum dot-doped polystyrene polymers
Space charge behavior of quantum dot-doped polystyrene polymers
This paper deals with the role played by the interface and bulk volume of the nanofiller about affecting the electrical properties of a nanocomposite material. For this purpose, a simple and completely amorphous matrix, polystyrene (PS), is used as base material, and core-shell quantum dots are exploited for simulating the structure of nanocomposites: CdSe core and CdSe-ZnS core-shell semiconductor quantum dots (QDs) are added into a PS matrix. The latter is to highlight the effect of the ZnS interface and as contrast to the core material. Dispersion and distribution of QDs are first microscopically observed and optimized, by including isopropyl alcohol in the manufacturing phase as an additional solvent. Among electrical properties the focus is on space charge accumulation, tested by means of the pulsed electroacoustic technique at 10 kV/mm and 50 kV/mm on CdSe and CdSe-ZnS doped PS composites. Results are then compared with a reference PS without QDs. Trap depth and density are also obtained by space charge measurement results. When CdSe QDs are added to PS, the trap density increases with respect to the baseline values measured on the unfilled polymer. In contrast, the ZnS shell around the CdSe core creates an additional trap level with lower trap depth, which increases charge mobility, thus turning homocharge into heterocharge accumulation. Therefore, the surface shell-structure of QD nanocrystals appears to significantly influence the space charge behavior of the nanocomposite, independently of the polymer.
1070-9878
753 - 761
Lei, Zhipeng
918141bc-5f4e-41c4-9179-ee46c345cc67
Fabiani, Davide
4d531d77-84e8-4e6a-8a01-931c3bea59bc
Bray, Tommaso
98fb4898-2402-44e2-9b67-4c65bf2fcd3c
Li, Chuanyang
ab90779d-916f-4292-bd2d-bbe64c5aa115
Wang, Xinyu
b0de6d39-87db-4bda-a097-a8ec50804a4a
Andritsch, Thomas
8681e640-e584-424e-a1f1-0d8b713de01c
Credi, Alberto
73c4d210-fac0-4769-bebc-9ac49c77ca51
La Rosa, Marcello
dfd11173-e2a9-44cf-a578-bf5ad0965bee
Lei, Zhipeng
918141bc-5f4e-41c4-9179-ee46c345cc67
Fabiani, Davide
4d531d77-84e8-4e6a-8a01-931c3bea59bc
Bray, Tommaso
98fb4898-2402-44e2-9b67-4c65bf2fcd3c
Li, Chuanyang
ab90779d-916f-4292-bd2d-bbe64c5aa115
Wang, Xinyu
b0de6d39-87db-4bda-a097-a8ec50804a4a
Andritsch, Thomas
8681e640-e584-424e-a1f1-0d8b713de01c
Credi, Alberto
73c4d210-fac0-4769-bebc-9ac49c77ca51
La Rosa, Marcello
dfd11173-e2a9-44cf-a578-bf5ad0965bee

Lei, Zhipeng, Fabiani, Davide, Bray, Tommaso, Li, Chuanyang, Wang, Xinyu, Andritsch, Thomas, Credi, Alberto and La Rosa, Marcello (2021) Space charge behavior of quantum dot-doped polystyrene polymers. IEEE Transactions on Dielectrics & Electrical Insulation, 753 - 761. (doi:10.1109/TDEI.2021.009223).

Record type: Article

Abstract

This paper deals with the role played by the interface and bulk volume of the nanofiller about affecting the electrical properties of a nanocomposite material. For this purpose, a simple and completely amorphous matrix, polystyrene (PS), is used as base material, and core-shell quantum dots are exploited for simulating the structure of nanocomposites: CdSe core and CdSe-ZnS core-shell semiconductor quantum dots (QDs) are added into a PS matrix. The latter is to highlight the effect of the ZnS interface and as contrast to the core material. Dispersion and distribution of QDs are first microscopically observed and optimized, by including isopropyl alcohol in the manufacturing phase as an additional solvent. Among electrical properties the focus is on space charge accumulation, tested by means of the pulsed electroacoustic technique at 10 kV/mm and 50 kV/mm on CdSe and CdSe-ZnS doped PS composites. Results are then compared with a reference PS without QDs. Trap depth and density are also obtained by space charge measurement results. When CdSe QDs are added to PS, the trap density increases with respect to the baseline values measured on the unfilled polymer. In contrast, the ZnS shell around the CdSe core creates an additional trap level with lower trap depth, which increases charge mobility, thus turning homocharge into heterocharge accumulation. Therefore, the surface shell-structure of QD nanocrystals appears to significantly influence the space charge behavior of the nanocomposite, independently of the polymer.

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Accepted/In Press date: 28 February 2021
e-pub ahead of print date: 10 June 2021

Identifiers

Local EPrints ID: 447212
URI: http://eprints.soton.ac.uk/id/eprint/447212
ISSN: 1070-9878
PURE UUID: 3ebce0ae-cc1d-4931-8f65-797450e8616c
ORCID for Xinyu Wang: ORCID iD orcid.org/0000-0001-9434-2906
ORCID for Thomas Andritsch: ORCID iD orcid.org/0000-0002-3462-022X

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Date deposited: 04 Mar 2021 17:47
Last modified: 21 Sep 2021 04:01

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Contributors

Author: Zhipeng Lei
Author: Davide Fabiani
Author: Tommaso Bray
Author: Chuanyang Li
Author: Xinyu Wang ORCID iD
Author: Thomas Andritsch ORCID iD
Author: Alberto Credi
Author: Marcello La Rosa

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