Title

First-principles study on structural transformation and surface chemistry of magic-sized clusters

Alternative Title

매직 크기 클러스터의 구조 변화와 표면 화학에 대한 제일 원리 이론 연구

DGIST Authors

Doeun Shim ; Joongoo Kang ; Jiwoong Yang

Advisor

강준구

Co-Advisor(s)

Jiwoong Yang

Issued Date

2023

Awarded Date

2023-02-01

Citation

Doeun Shim. (2023). First-principles study on structural transformation and surface chemistry of magic-sized clusters. doi: 10.22677/THESIS.200000656117

Type

Thesis

Description

First-principles simulations, ab initio simulated spectrascopy, magic-sized clusters, structural transformation, bond-exchange defect

Table Of Contents

I. Introduction 1
1.1. Semiconductor nanoparticles 1
1.1.1. Colloidal semiconductor quantum dots 1
1.1.2. Classical nucleation model 1
1.1.3. Non-classical nucleation model 3
1.2. Inorganic semiconductor nanoclusters 4
1.2.1. Magic-sized clusters 5
1.2.2. Experimental observation of destabilization of In37P20 magic-sized cluster 6
1.2.3. Experimental observation of cluster isomerization 7
II. Theoretical framework 9
2.1. Density-functional theory 9
2.1.1. Many-body Schrödinger equation 9
2.1.2. Mean-field approximation 11
2.1.3. Hartree-Fock approximation 13
2.1.4. Kohn-Sham equation 14
2.1.5. Approximations to exchange and correlation potentials 15
2.1.6. Modern DFT algorithm 16
III. Results and discussion 1: Destabilization process of In37P20 magic-sized cluster 19
3.1. Calculation details 22
3.1.1. DFT calculations of the MSC stability 22
3.1.2. UV−vis absorption simulation 23
3.2. High-temperature MD simulations of InP MSC 24
3.3. Key questions on the MSC destabilization 29
3.4. Mechanism for thermal destabilization of InP MSC 31
3.5. Quantitative analysis of the energetics in MSC destabilization 39
3.6. UV−vis absorption and XRD simulations 42
3.7. Comparison with the group II-VI MSC isomerization 53
3.8. Conclusions 55
IV. Results and discussion 2: Multiscale isomerization of Cd41S20 magic-sized cluster 57
4.1. Calculation details 59
4.1.1. DFT calculations of the MSC stability 59
4.1.2. Vibrational mode calculations 61
4.1.3. Transition-state calculations 61
4.1.4. XRD simulation 61
4.1.5. UV−vis absorption simulation 62
4.2. Model construction 63
4.3. FTIR spectrum of CdS MSC 67
4.4. Bond-exchange isomerization 71
4.5. Multiscale isomerization 76
4.6. Conclusions 82
V. References 83
VI. Korean summary 93

URI

http://hdl.handle.net/20.500.11750/45693
http://dgist.dcollection.net/common/orgView/200000656117

DOI

10.22677/THESIS.200000656117

Degree

Doctor

Department

Department of Physics and Chemistry

Publisher

DGIST

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