Title Page
Abstract
Contents
List of abbreviations 12
Chapter 1. Introduction 18
1.1. References 21
Chapter 2. Fundamentals 26
2.1. Hybrid organic-inorganic lead halide perovskite 26
2.1.1. Methylammonium lead halide perovskite (MAPbX₃) crystal structure 26
2.1.2. Electronic structure and bandgap engineering of MAPbX₃ 28
2.1.3. Excitons 30
2.2. Optical microcavities 34
2.2.1. Simple Fabry-Perot microcavity 34
2.2.2. Dispersion of cavity photons in 2D planar FP cavity 37
2.3. Light-matter interactions 40
2.3.1. Weak coupling regime 40
2.3.2. Strong coupling regime 42
2.3.3. Coupled oscillator model for exciton-polaritons 43
2.4. References 47
Chapter 3. Experimental Details 50
3.1. Growth methods 50
3.1.1. Antisolvent vapor-assisted crystallization method 50
3.1.2. Electron beam evaporation 53
3.2. Characterization techniques 55
3.2.1. Ellipsometry 55
3.2.2. Scanning electron microscope 57
3.2.3. Photoluminescence spectroscopy 59
3.2.4. Angle-resolved photoluminescence spectroscopy 61
3.2.5. Micro-absorption spectroscopy 64
Chapter 4. Observation of multimode exciton-polaritons in self-assembled hybrid organic-inorganic perovskite microcavities 66
4.1. Introduction 67
4.2. Experimental details 69
4.2.1. Materials 69
4.2.2. Characterizations 69
4.3. Result and discussions 70
4.3.1. Growth and characterization 70
4.3.2. Multimode polaritons in MAPbBr₃ micro-platelet (MP) 72
4.3.3. Multimode Polaritons in MAPbBr₃ micro-ribbon (MR) 77
4.4. References 83
Chapter 5. Highly reflective distributed Bragg reflectors for planar microcavities: from modelling to experimentation 89
5.1. Introduction 90
5.2. Experimental details 92
5.2.1. Materials 92
5.2.2. Synthesis/Fabrication 92
5.2.3. Characterizations 92
5.3. Result and discussions 93
5.3.1. Design and simulations 93
5.3.2. Refractive index (n) and extinction coefficient (k) analysis 96
5.3.3. 7.5 pairs TiO₂/SiO₂ DBR 97
5.3.4. Monolithic microcavity (DBR/DBR) 99
5.3.5. Tamm plasmon microcavity (Metal/DBR) 102
5.4. References 105
Conclusion 109
Publications 111
Appendices 113
Appendix A. Boundary conditions for EM waves 113
Appendix B. Highly efficient solar steam generation by glassy carbon foam coated with two-dimensional metal chalcogenides 114
B.1. Introduction 115
B.2. Experimental details 117
B.3. Results and discussions 118
B.4. References 131
Appendix C. Energy balance analysis of the BSSG 135
Figure 1-1. Schematic illustration of reflection, transmission, absorption, and scattering of light. 18
Figure 2-1. The unit cell of cubic MAPbX₃. 26
Figure 2-2. Temperature-dependent phase transition of (a) MAPbBr₃ and (b) MAPbI₃, respectively. 27
Figure 2-3. The DFT calculated band structures of (a) MAPbI₃, (b) MAPbBr₃ and (c) MAPbCl3,respectively. (d) UV-Vis absorption and PL spectra of MAPbX₃, where X=Cl (black), Br (green) and I (wine). 29
Figure 2-4. The typical schematic illustration of a Wannier-Mott (large Bohr radius) and a Frenkel exciton (small Bohr radius). 31
Figure 2-5. The schematic of a simple band structure diagram, showing the typical conduction and valance bands along with the Rydberg excitonic states corresponding to n=1, 2. Eg represents the energy separation...[이미지참조] 32
Figure 2-6. (a) Schematic representation of a simple semiconductor FP cavity. (b) FP cavity modes with m=1, 2, and 3. (c) The transmittance spectrum showing the frequencies/energies corresponding to the FP... 36
Figure 2-7. (a) Schematic illustration of an ideal 2D planar FP microcavity. (b) The parabolic dispersion of an FP cavity mode. (c) The light cone (blue) collected by the microscope objective. 39
Figure 2-8. (a) schematic and (b) graphical/spectral demonstration of an off-resonance semiconductor microcavity system working in the weak coupling regime. (c) The PL spectrum shows 0.5 times decrease... 40
Figure 2-9. (a) schematic and (b) graphical/spectral demonstration of an on-resonance semiconductor microcavity system working in the weak coupling regime. (c) The PL spectrum shows 1.5 times increase in... 41
Figure 2-10. (a) schematic and (b) graphical/spectral demonstration of a semiconductor microcavity system working in the strong coupling regime. (c) Both the PL and the reflection spectrums show the splitting of... 42
Figure 2-11. Dispersion of the exciton-polariton with (a) positive, (b) zero, and (c) negative cavity detuning with (d, e and f) their corresponding Hopfield coefficients, respectively. 45
Figure 3-1. (a) Schematic illustration of the AVC mechanism for the growth of bulk perovskite single crystals. (b, c, and d) digital images of bulk MAPbBr₃, MAPbI₃ and (PEA)₂PbI₄, respectively. 51
Figure 3-2. (a) Modified AVC growth mechanism of the perovskite microcrystals. (b, c, and d) OM images of MAPbBr₃, MAI₃ and (PEA)₂PbI₄, respectively. 52
Figure 3-3. Schematic illustration of electron beam evaporation. 54
Figure 3-4. Schematic representation of spectroscopic ellipsometry. 56
Figure 3-5. Schematic illustration of a scanning electron microscope. 58
Figure 3-6. Schematic of the photoluminescence spectroscopy setup. 60
Figure 3-7. Schematic of the angle-resolved photoluminescence spectroscopy setup. 62
Figure 3-8. Ray diagram demonstrating the BFP of an objective lens. 63
Figure 3-9. Schematic of the micro-absorption spectroscopy setup. 65
Figure 4-1. Growth and characterization of MAPbBr₃ microcrystals. (a) The systematic growth process of the MAPbBr₃ microcrystals. (b and c) The dark-field optical microscope images of the platelet- and ribbon-... 71
Figure 4-2. Strong exciton-photon coupling in MAPbBr₃ MP. (a) The SEM image of the perovskite MP shows sharp and featureless surface with lateral (x-y) dimensions 80 × 70 μm. (b) The alpha step height... 74
Figure 4-3. The COM fitting of the MEPs in the perovskite MP. (a-f) The COM-fitted UPBs (green) and LPBs (blue) obtained via the strong coupling between the exciton (black) and the multiple uncoupled FP... 75
Figure 4-4. The Hopefield coefficients of the perovskite MP. (a-f) The excitonic |X|² and the photonic (|C|²) fractions of the polariton mode in the perovskite MP with an associated cavity mode number (m=29... 76
Figure 4-5. Strong exciton-photon coupling in the MAPbBr₃ MR. (a) The SEMimage of the perovskite MR shows sharp and featureless MR surface with lateral (x-y) dimension 3.87 × 150 μm. (b) The alpha step... 78
Figure 4-6. The COM fitting of the MEPs in the perovskite MP. (a-f) The COM-fitted UPBs (green) and LPBs (blue) obtained via the strong coupling between the exciton (black) and the multiple uncoupled FP... 79
Figure 4-7. The Hopefield coefficients of the perovskite MR. (a-e) The excitonic |X|² and the photonic (|C|²)fractions of the MEPs (m=33-37) in the perovskite MR. 80
Figure 4-8. Young's double-slit-like interference pattern of MAPbBr₃ MR. (a) The ARPL mapping when the short axis (x-axis) of the MR is set parallel to the spectrometer entrance slit. The mapping displays five... 82
Figure 5-1. The partial reflection and transmission of the incident light in (a) single and (b) multilayer thin films at oblique incidence. (c) The schematic of a DBR depicting that light reflected from each interface... 95
Figure 5-2. Refractive index of (a) SiO₂ and (b) TiO₂ thin films grown on the quartz substrate, respectively. 96
Figure 5-3. (a) Schematic representation of 7.5 pairs TiO₂/ SiO₂ DBR. (b) Transmission electron microscope (TEM) images of the sample on a quartz substrate. The high-resolution TEM image (right side top and... 98
Figure 5-4. (a) Schematic representation of the monolithic microcavity. (b) The corresponding low-resolution TEM image. (c, d & e) EDS elemental mapping of the microcavity constituents i.e., Ti, Si, and... 100
Figure 5-5. (a) The simulated and the experimentally measured parabolic dispersions of the cavity mode. (b) The experimentally measured transmittance spectra of the monolithic microcavity acquired at multiple angles. 101
Figure 5-6. (a) Schematic representation of the Tamm plasmon microcavity. (b) Simulated refractive index and the electric field intensity distribution across the entire microcavity structure at 674 nm. (c) Simulated... 103
Figure 5-7. (a) The simulated and the experimentally measured parabolic dispersions of the cavity mode. (b) The experimentally measured transmittance spectra of the Tamm plasmon microcavity acquired at... 104