Title Page
Contents
ABSTRACT 15
Ⅰ. INTRODUCTION 19
1. Perovskite 19
1.1. Perovskite materials 19
1.2. Perovskite solar cells 22
2. Interfacial engineering 25
2.1. Effect of interfacial engineering 25
2.2. Interfacial engineering with O-P4VP 30
Ⅱ. MATERIALS AND METHODS 33
1. Materials 33
2. Synthesis of perovskite precursor solution 34
3. Fabrication of perovskite solar cell 34
4. Fabrication of electron-only devices 36
5. Characterization 36
Ⅲ. RESULTS AND DISCUSSION 39
1. Effect of UVO treatment on chemical structure of P4VP 39
2. Effect of O-P4VP on defect passivation of SnO₂ 50
3. Effect of O-P4VP on morphology control of perovskite 56
4. Device performance of solar cell 69
4.1. Power conversion efficiency (PCE) 69
4.2. External quantum efficiency (EQE) 70
4.3. Stability test 74
Ⅳ. CONCLUSION 76
Ⅴ. REFERENCES 77
ABSTRACT IN KOREAN 93
Table 1. Time-resolved photoluminescence (TRPL) parameters of the perovskite deposited onto the glass/SnO₂/O-P4VP substrates fitted... 67
Table 2. Photovoltaic parameters of fabricated solar cells measured under a standard AM 1.5 G illumination of 100 mW cm⁻². 72
Figure 1. Schematic diagram of ABX₃ perovskite crystal structure. 20
Figure 2. Perovskite materials-based optoelectronic devices. 21
Figure 3. Scheme of approaches to prevent degradation and enhance the efficiency and stability of perovskite solar cells. 24
Figure 4. Various defect passivation methods for perovskite solar cells. 29
Figure 5. Schematic illustrating the passivation process of SnO₂-ETLs using a P4VP solution. After the deposition and UV-ozone treatment... 32
Figure 6. FTIR spectra of the P4VP and O-P4VP (0.4 wt%) samples. 40
Figure 7. Photographs of (A) pristine P4VP (0.4 wt%), (B) O-P4VP (0.4 wt%), and (C) O-P4VP (5 wt%). These were prepared on a quartz glass... 41
Figure 8. OM images of (A) pristine P4VP, (B) Si wafer after washing the P4VP film in the DMF/DMSO solution, (C) O-P4VP (UV-ozone... 42
Figure 9. UV-visible spectra of the SnO₂/P4VP, SnO₂/O-P4VP (0.4 wt%), and SnO₂/O-P4VP (5 wt%) samples. 46
Figure 10. Photographs of the PbI₂ (left) and PbI₂/P4VP (right) solution. PbI₂ and P4VP solutions were prepared by dissolving 1.3 M of PbI₂ and... 47
Figure 11. (A, B) XRD spectrum of the perovskite deposited on glass/P4VP (0.4 wt%) and glass/O-P4VP (0.4 wt%), respectively.... 48
Figure 12. (B, C) Magnified IR spectra of the O-P4VP and O-P4VP/PbI₂ composites corresponding to the C=O and C-N=C bonds,... 49
Figure 13. (A) Schematic illustrating the passivation of oxygen vacancies in the SnO₂ surface with O-P4VP chains. XPS spectra of the... 53
Figure 14. Tauc plots of the pristine SnO₂ and SnO₂/O-P4VP samples. 54
Figure 15. (A) UPS spectra of the SnO₂/O-P4VP (0.2 wt%) and SnO₂/O-P4VP (0.7 wt%) for the high binding energy regime. (B) UPS... 55
Figure 16. Photographs presenting the contact angle of a perovskite solution dripped on (A) ITO/SnO₂ and (B) ITO/SnO₂/O-P4VP (0.4 wt%). 57
Figure 17. AFM height images of (A) ITO/SnO₂, (B) ITO/SnO₂/O-P4VP, (C) ITO/SnO₂/O-P4VP (0.4 wt%), and (D) ITO/SnO₂/O-P4VP (0.7 wt%)... 58
Figure 18. (A) Schematic illustrating the crystal growth of perovskite in the intermediate phase owing to the coordination between Pb²⁺ and... 61
Figure 19. Size of the perovskite crystallites at the different concentrations of P4VP (0, 0.2, 0.4, and 0.7 wt%). 62
Figure 20. (A) Steady-state photoluminescence (PL) spectra and (B) time-resolved PL spectra of the pristine perovskite and O-... 66
Figure 21. Steady-state PL spectra of the perovskite deposited onto the glass/SnO₂/O-P4VP substrates (concentration of P4VP=0, 0.2,... 68
Figure 22. (A) Cross-section SEM image of the device. (B) Schematic of the energy diagram of the device. J-V curves of the devices... 71
Figure 23. Power conversion efficiency (PCE) histograms of (A) pristine and (B) O-P4VP (0.4 wt%) devices. The value in the bracket... 73
Figure 24. Normalized PCEs of the pristine and O-P4VP (0.4 wt%) device measured under continuous 1 sun illumination for 720 h at 25... 75