Title Page
Contents
Abstract 20
요약 23
Chapter 1. Background 27
1.1. Organic-inorganic hybrid perovskite 30
1.2. Properties of organic-inorganic hybrid perovskite 31
1.3. Perovskite solar cells 33
1.3.1. Structure type 33
1.3.2. Working principle 36
1.3.3. Performance parameters 38
1.4. Optimization strategies of PeSCs 41
1.4.1. Component Engineering 41
1.4.2. Solvent engineering 43
1.4.3. Additive engineering 45
1.4.4. Interface engineering 49
1.5. Stability issue of PeSCs 50
1.5.1. Degradation of the perovskite active layer 51
1.5.2. Electrode degradation 54
1.5.3. Degradation of the charge transport layer 56
Chapter 2. Experimental section 59
2.1. Materials preparation 59
2.2. Device preparation 60
2.2.1. p-i-n perovskite solar cell fabrication 60
2.2.2. n-i-p perovskite solar cell fabrication 61
2.2.3. Fabrication of solar modules 63
2.3. Replication of the plants' epidermal surface onto a UV absorption layer 64
2.4. Device packaging 65
2.5. Characterizations 65
2.5.1. Film characterizations 65
2.5.2. Characterization of the UV absorption layer 66
2.5.3. Device characterizations 67
2.6. DFT calculations 67
Chapter 3. Effective multifunctional additive engineering for efficient and stable inverted perovskite solar cells 69
3.1. Introduction 69
3.2. Results and discussion 72
3.3. Conclusion 92
Chapter 4. Tailoring the interface with a multifunctional ligand for highly efficient and stable FAPbI₃ perovskite solar cells and modules 93
4.1. Introduction 93
4.2. Results and discussion 97
4.3. Conclusion 128
Chapter 5. Effective encapsulation method for highly stable perovskite solar cells by introducing UV absorber with biomimetic textures and heat sinker with reduced graphene oxide composite layer 129
5.1. Introduction 129
5.2. Results and discussion 132
5.3. Conclusion 152
Chapter 6. Conclusion 153
References 156
Table 3.1. Photovoltaic parameters of the PeSCs based on MAPbI₃ films with and without 2HT. 79
Table 3.2. Photovoltaic parameters of MAPbI₃, and 2HT-modified MAPbI₃ based solar cells. 80
Table 3.3. Fitting parameters of the TRPL spectra according to the formula y=A1e-x1/τ1 + A2e-x2/τ2 + B.[이미지참조] 84
Table 4.1. TRPL fitting parameters of the perovskite films. The data was fitted using bi-exponential decay equation y=A₁exp (−x⁄τ₁) + A₂exp (−x⁄τ₂) + y₀,...[이미지참조] 111
Table 4.2. Photovoltaic parameters obtained from the J-V curves of the control and target champion devices. 117
Table 4.3. Statistical photovoltaic parameters of the PeSCs with various concentrations of 4HPA treatment. 118
Table 4.4. Photovoltaic parameters of the best and average for the devices of control and after post-treatment with different ligands. 121
Table 5.1. Photovoltaic parameters of PeSCs coated with the UV-AR loaded with different amounts (0.5 to 2 wt. %) of UV-9. 138
Figure 1.1. Power Conversion Efficiency of solar cells recorded by American National Renewable Energy Laboratory (NREL). 29
Figure 1.2. Cubic crystal structure of organic-inorganic hybrid perovskite. 31
Figure 1.3. Three typical device structures of perovskite solar cells: (a) mesoporous, (b) regular planar structure, and (c) inverted planar structure. 36
Figure 1.4. Schematic diagram of the working mechanism of PeSCs. 38
Figure 1.5. Schematic diagram of the J-V curve of PeSCs. 39
Figure 1.6. Component engineering fabricates p-n homojunction inside perovskite layer. 43
Figure 1.7. Green, low-toxic ethyl acetate for one-step preparation of perovskite thin film anti-solvent and Spiro-OMeTAD solvent. 45
Figure 1.8. Schematic illustrations of in-situ cross-linked organic/perovskite films. 46
Figure 1.9. Schematic illustrations of the perovskite film formation and fabrication steps. Perovskite grain growth induced by a conventional small... 48
Figure 1.10. Interface engineering and interface modification materials for PeSCs. 50
Figure 1.11. Degradation factors affecting the stability of perovskite. 52
Figure 1.12. Schematic diagram of the formation mechanism of AgI. 55
Figure 1.13. (a) Schematics of three devices with different HTL/electrode configurations. (b) Top view SEM images of fresh/degraded Au electrodes... 56
Figure 2.1. Schematic of the replication process. 64
Figure 3.1. (a) Molecular structure of 2HT. (b) Diagram illustrating the mechanism of 2HT passivation. (c) FTIR spectra of 2HT, pristine perovskite, and... 74
Figure 3.2. The FTIR spectra for 2HT, pristine perovskite, and 2HT-modified perovskite films. 75
Figure 3.3. XPS full spectra of (a) control and (b) 2HT-modified perovskite films. High-resolution XPS spectra of (c) S 2p and (d) I 3d of perovskite film with and... 75
Figure 3.4. (a) Cross-sectional image of a PeSC with the 2HT-modified film. (b) J-V curves of the devices without and with 2HT were recorded under reverse and... 78
Figure 3.5. Cross−sectional SEM images of PeSCs with control and 2HT-modified films. 79
Figure 3.6. The PCE distribution of PeSCs at different concentrations of 2HT (5 solar cells of each concentration). 80
Figure 3.7. (a) XRD patterns of the control and 2HT-modified perovskite films. Top-view SEM images of the control (b) and 2HT-modified (c) perovskite films.... 82
Figure 3.8. AFM images of (a) control and (b) 2HT-modified perovskite films. 84
Figure 3.9. (a, b) UPS profiles and (c) energy level diagrams of the control and 2HT-modified perovskite films. (d) Light-intensity-dependent Voc of the control... 88
Figure 3.10. Tauc plots of the perovskite films with and without 2HT. 88
Figure 3.11. Light-intensity-dependent Jsc of the control and 2HT-modified PeSCs. 89
Figure 3.12. (a) Photographs showing the time-dependent morphological changes of perovskite films. (b) Variation in perovskite films' XRD patterns and (c) UV-... 91
Figure 4.1. (a) Schematic diagram of the interaction between 4HPA and the FAPbI₃ perovskite film, including the coordination of the carbonyl unit with Pb,... 99
Figure 4.2. Optimized molecular configurations and corresponding (a) HOMO and (b) LUMO profiles of 4HPA. 100
Figure 4.3. ESP plots of PA, 4HPA and 5HPA. 102
Figure 4.4. UV-vis absorption spectra of 4HPA and 4HPA:PbI₂ solutions. 102
Figure 4.5. FTIR of the powder of 4HPA and 4HPA: PbI₂ blend. 103
Figure 4.6. (a) FTIR spectra of the ligand, control, and target films; (b) the local magnification curve of FTIR spectra. 103
Figure 4.7. The entire XPS spectra of (a) 4HPA, (b) control film, and (c) target film. 105
Figure 4.8. XPS spectra of N 1s for pure 4HPA and 4HPA treated perovskite film. 106
Figure 4.9. (a) The side view and (b) top view of the 4HPA ligand in the optimized molecular geometries arranged on the surface of perovskite film. 106
Figure 4.10. (a) XRD patterns of the control and target films. Top-view SEM images of the control (b) and target (c) perovskite films. (d) UV–vis absorption,... 108
Figure 4.11. (a) Top-view SEM image of the target perovskite film. SEM-EDS mappings of C (b), N (c), Pb (d), I (e), and O (f) for target film deposited onto the... 109
Figure 4.12. Grain size distribution of perovskite films without or with 4HPA treatment. 109
Figure 4.13. Surface AFM topographies of control (a) and target (b) perovskite films. 110
Figure 4.14. (a) UPS results of the corresponding perovskite thin films. (b) band alignment of the PeSCs after 4HPA post-treatment. (c) Mott–Schottky... 113
Figure 4.15. Tauc plot of the perovskite films on glass substrate. 114
Figure 4.16. Cross-sectional SEM images of PeSCs with control and 4HPA-treated films. 114
Figure 4.17. (a) Cross-sectional SEM image of the target PeSC. (b) J–V curves of the control and target champion devices for different scan directions. (c) Steady-... 116
Figure 4.18. The PCE distribution of the PeSCs with different concentrations of 4HPA treatment. 118
Figure 4.19. Current J-V curves of the four PeSCs under AM 1.5G irradiation(100 mW/cm²). 120
Figure 4.20. (a) Jsc and (b) Voc versus the light intensity curves for the control and target PeSCs. (c) Nyquist plots of the control and target PeSCs. The inset... 123
Figure 4.21. (a) PCE decay of the corresponding PeSCs was measured under ambient environmental conditions with 25% humidity in the dark at room... 125
Figure 4.22. Static contact angle measurements with water on top of different perovskite films. 126
Figure 5.1. (a) Dynamic nature of the UV-9. (b) Fabrication process for UV-absorbing layer. (c) SEM image of the replicated rose texture. (d) Scheme of the... 133
Figure 5.2. UV-vis absorption spectra of the UV-absorbing layer at increasing UV-9 concentration. 136
Figure 5.3. The reflectance spectra of NOA-63 and surface rose texture NOA-63. 136
Figure 5.4. (a) Device configuration. (b) The cross-sectional SEM image of the PeSC. (c) J-V curves of the PeSCs without and with the UV-RT layer. (d) IPCE... 138
Figure 5.5. UV–vis absorption spectra of the control perovskite film and UV-aged perovskite film based on FTO/TiO₂/FAPbI₃ (a) and UV-RT/FTO/TiO₂/FAPbI₃ (b).... 140
Figure 5.6. Structure of PeSC encapsulated with rGO/NOA-63 encapsulation film. 142
Figure 5.7. (a) The NOA-63 layer-coated glass plate (NOA-63/glass) and (b) the rGO/NOA-63 layer-coated glass plate (rGO/NOA-63/glass) were placed on the... 143
Figure 5.8. Infrared thermal camera images of (a) the NOA-63 coated PeSC and (b) the rGO/NOA-63 coated PeSC. (Hot plate at 95 °C) 143
Figure 5.9. ATR-FTIR spectra of (a) the undoped Spiro-OMeTAD and (b) Spiro+LiFTSI+tBP films after aging at 90 °C. TOF-SIMS depth profiles for the... 145
Figure 5.10. (a) Results of the aging test on the three series of PeSCs: bare PeSC, UV-RT/PeSC. (i.e., UV-RT layer on the front side), and UV-RT/encapsulation... 149
Figure 5.11. UV stability of OSCs under 60 mW/cm² UV light (wavelength of 365 nm) for 8 h in nitrogen condition. 151