東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

Synthesis, Core-Shell Growth, and Su...

Sun, Haochen.

Linked to FindBook

Google Book

Amazon

博客來

Synthesis, Core-Shell Growth, and Surface Chemistry of 2-Dimensional Cadmium Telluride and Cadmium Selenide Nanocrystals.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Synthesis, Core-Shell Growth, and Surface Chemistry of 2-Dimensional Cadmium Telluride and Cadmium Selenide Nanocrystals./
Author:	Sun, Haochen.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2021,
Description:	197 p.
Notes:	Source: Dissertations Abstracts International, Volume: 82-08, Section: B.
Contained By:	Dissertations Abstracts International82-08B.
Subject:	Chemistry. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28265164
ISBN:	9798569941537

Synthesis, Core-Shell Growth, and Surface Chemistry of 2-Dimensional Cadmium Telluride and Cadmium Selenide Nanocrystals.
Sun, Haochen.

Synthesis, Core-Shell Growth, and Surface Chemistry of 2-Dimensional Cadmium Telluride and Cadmium Selenide Nanocrystals. - Ann Arbor : ProQuest Dissertations & Theses, 2021 - 197 p.

Source: Dissertations Abstracts International, Volume: 82-08, Section: B.

Thesis (Ph.D.)--Washington University in St. Louis, 2021.

This item is not available from ProQuest Dissertations & Theses.

This dissertation presents the synthesis, shell deposition, and surface ligand-exchange chemistry of 2-dimensional cadmium telluride and cadmium selenide nanocrystals. Flat, colloidal 2-dimensional CdTe and CdSe nanoplatelets are promising materials for optical and electronic applications. The research presented here will enable better understanding of their properties and facilitate further applications.First, a new tellurium precursor, tris(dimethylamino)phosphine telluride is readily prepared and is found to have superior reactivity than the trialkylphosphine tellurides that are commonly used for nanocrystal synthesis. Wurtzite CdTe nanoplatelets, (CdTe)13 magic-size nanoclusters, and CdTe quantum wires are synthesized with this precursor, and are fully characterized. It is demonstrated that in amine solvent, this tellurium precursor undergoes transamination reactions, affording (Me2N)x(RHN)3−xPTe. A reaction mechanism is proposed.Second, CdS and CdSe shells are deposited on wurtzite CdTe nanoplatelets in a cyclic manner, allowing fine tuning of the absorption spectrum of the nanoplatelets across the visible spectrum, while maintaining the morphology, lattice structure, and the smooth surface texture of the nanoplatelets. The CdTe nanoplatelets having an initial thickness of 1.9 nm are converted to CdTe−CdS and CdTe−CdSe core−shell nanoplatelets having maximum thicknesses of 3.0 and 6.3 nm, respectively. Shell deposition is found to greatly improve the stability of the nanoplatelets. CdS shells are also deposited on CdSe nanoplatelets.Third, surface ligand-exchange chemistry of CdSe and CdTe nanoplatelets is investigated. Surface ligands are important in determining the optical and electronic properties of semiconductor nanocrystals. We demonstrate that the Z-type ligation on CdSe nanoplatelets having the zinc-blende structure, large surface areas, and minimal strain distortions can be exchanged for L-type ligation by ethylenediamine (en), affording nanoplatelets having a composition of (CdSe)3[en]0.67, and this process can be reversely exchanged by Z-type ligands such as CdCl2 and Zn(oleate)2, hence significantly expanding the types of available surface ligand exchange reactions on CdSe nanoplatelets. Fourth, we also compare and contrast the ligand exchange behavior on nonpolar, wurtzite and polar, zinc-blende CdTe nanoplatelet surfaces. We show that wurtzite CdTe nanoplatelets of composition (CdTe)[(n-octylamine)0.15(oleylamine)0.27] undergo reversible L-type to Z-type ligand exchange with Cd(oleate)2, Zn(oleate)2, CdCl2, and ZnCl2. However, the wurtzite CdTe nanoplatelets are unstable with anionic X-type ligation. In contrast, zinc blende CdTe nanoplatelets of composition (CdTe)3[Cd(carboxylate)2]0.74 undergo semi-reversible X-type to X'-type ligand exchange with CdCl2, CdBr2, and ZnCl2, but do not exhibit Z-type to L-type ligand exchange. The wurtzite nanoplatelets with nonpolar surfaces prefer neutral L- or Z-type ligation, whereas the zinc-blende nanoplatelets with polar surfaces prefer anionic X-type ligation.

ISBN: 9798569941537Subjects--Topical Terms:

516420
Chemistry.
Subjects--Index Terms:

Core-shell growth

Synthesis, Core-Shell Growth, and Surface Chemistry of 2-Dimensional Cadmium Telluride and Cadmium Selenide Nanocrystals.
LDR:04293nmm a2200349 4500 001 2281555
005 20210920103542.5
008 220723s2021 ||||||||||||||||| ||eng d
020 $a 9798569941537
035 $a (MiAaPQ)AAI28265164
035 $a AAI28265164
040 $a MiAaPQ $c MiAaPQ
100 1 $a Sun, Haochen. $0 (orcid)0000-0001-7390-843X $3 3560219
245 1 0 $a Synthesis, Core-Shell Growth, and Surface Chemistry of 2-Dimensional Cadmium Telluride and Cadmium Selenide Nanocrystals.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2021
300 $a 197 p.
500 $a Source: Dissertations Abstracts International, Volume: 82-08, Section: B.
500 $a Advisor: Buhro, William E.
502 $a Thesis (Ph.D.)--Washington University in St. Louis, 2021.
506 $a This item is not available from ProQuest Dissertations & Theses.
506 $a This item must not be sold to any third party vendors.
520 $a This dissertation presents the synthesis, shell deposition, and surface ligand-exchange chemistry of 2-dimensional cadmium telluride and cadmium selenide nanocrystals. Flat, colloidal 2-dimensional CdTe and CdSe nanoplatelets are promising materials for optical and electronic applications. The research presented here will enable better understanding of their properties and facilitate further applications.First, a new tellurium precursor, tris(dimethylamino)phosphine telluride is readily prepared and is found to have superior reactivity than the trialkylphosphine tellurides that are commonly used for nanocrystal synthesis. Wurtzite CdTe nanoplatelets, (CdTe)13 magic-size nanoclusters, and CdTe quantum wires are synthesized with this precursor, and are fully characterized. It is demonstrated that in amine solvent, this tellurium precursor undergoes transamination reactions, affording (Me2N)x(RHN)3−xPTe. A reaction mechanism is proposed.Second, CdS and CdSe shells are deposited on wurtzite CdTe nanoplatelets in a cyclic manner, allowing fine tuning of the absorption spectrum of the nanoplatelets across the visible spectrum, while maintaining the morphology, lattice structure, and the smooth surface texture of the nanoplatelets. The CdTe nanoplatelets having an initial thickness of 1.9 nm are converted to CdTe−CdS and CdTe−CdSe core−shell nanoplatelets having maximum thicknesses of 3.0 and 6.3 nm, respectively. Shell deposition is found to greatly improve the stability of the nanoplatelets. CdS shells are also deposited on CdSe nanoplatelets.Third, surface ligand-exchange chemistry of CdSe and CdTe nanoplatelets is investigated. Surface ligands are important in determining the optical and electronic properties of semiconductor nanocrystals. We demonstrate that the Z-type ligation on CdSe nanoplatelets having the zinc-blende structure, large surface areas, and minimal strain distortions can be exchanged for L-type ligation by ethylenediamine (en), affording nanoplatelets having a composition of (CdSe)3[en]0.67, and this process can be reversely exchanged by Z-type ligands such as CdCl2 and Zn(oleate)2, hence significantly expanding the types of available surface ligand exchange reactions on CdSe nanoplatelets. Fourth, we also compare and contrast the ligand exchange behavior on nonpolar, wurtzite and polar, zinc-blende CdTe nanoplatelet surfaces. We show that wurtzite CdTe nanoplatelets of composition (CdTe)[(n-octylamine)0.15(oleylamine)0.27] undergo reversible L-type to Z-type ligand exchange with Cd(oleate)2, Zn(oleate)2, CdCl2, and ZnCl2. However, the wurtzite CdTe nanoplatelets are unstable with anionic X-type ligation. In contrast, zinc blende CdTe nanoplatelets of composition (CdTe)3[Cd(carboxylate)2]0.74 undergo semi-reversible X-type to X'-type ligand exchange with CdCl2, CdBr2, and ZnCl2, but do not exhibit Z-type to L-type ligand exchange. The wurtzite nanoplatelets with nonpolar surfaces prefer neutral L- or Z-type ligation, whereas the zinc-blende nanoplatelets with polar surfaces prefer anionic X-type ligation.
590 $a School code: 0252.
650 4 $a Chemistry. $3 516420
650 4 $a Nanoscience. $3 587832
653 $a Core-shell growth
653 $a Nanocrystals
653 $a Nanoplatelets
690 $a 0485
690 $a 0565
710 2 $a Washington University in St. Louis. $b Chemistry. $3 2094917
773 0 $t Dissertations Abstracts International $g 82-08B.
790 $a 0252
791 $a Ph.D.
792 $a 2021
793 $a English
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=28265164