Integrated Material and Device Engineering Towards Reliable, High-Performance Perovskite Solar Cells

Abstract

Organic-inorganic hybrid perovskites are a diverse, versatile, and multifunctional material class that have soared to prominence because of their application in solar cells. Perovskite Solar Cells (PVKSCs) are promising candidates for addressing the scalability challenge of solar based renewable energy as they combine merits of high-power conversion efficiency with facile manufacturability and low cost. The dynamically evolving research field has made immense progress in capitalizing on amazing structure-property-processing-performance traits of hybrid perovskites. At this point, research efforts for solving material and device level challenges of PVKSCs are vital in their progression towards commercialization. The unifying research objective for works presented in this doctoral dissertation is improvement of PVKSC reliability and performance. I have utilized and integrated a wide-range of material and device perspectives for attaining better comprehension of inherent challenges, solving key issues, and facilitating advancement of PVKSCs. Chapter 1 (Introduction) provides an overview of PVKSCs including hybrid perovskites material characteristics, multifaceted roles of interfaces in device engineering, evolution of PVKSC research landscape, and an outlook of scalability-durability-sustainability challenges in their path towards commercialization. Subsequently, the subject matter in this dissertation is broadly categorized into three parts: investigation of complex hysteresis instability in PVKSCs (Part A: Chapters 2-3), development of perovskite tandem solar cells (Part B: Chapters 4-5), and progression towards next generation perovskite tandem solar cells (Part C: Chapters 6-7). Chapter 2 comprises a case study to understand how interfaces mediate hysteresis behavior in PVKSCs. Chapter 3 comprises a case study to understand how perovskite compositional modification influences hysteresis behavior in PVKSCs. Chapter 4 illustrates an approach to alleviate the issue of photoinduced phase segregation in large bandgap PVKSCs. Chapter 5 illustrates design of perovskite tandem solar cells, approach to minimize the photovoltage loss in small and large bandgap PVKSCs, and fabrication of monolithic (2-Terminal) tandem devices. Chapter 6 demonstrates an approach to overcome the photovoltage bottleneck in large bandgap PVKSCs. Chapter 7 investigates the impact of compositional modification on bandgap bowing and optoelectronic quality in Pb-Sn hybrid perovskites to identify the optical composition for small bandgap PVKSCs. Chapter 8 (Conclusion) concludes this dissertation with summary of results, highlights of extensions through collaborative work, intellectual merits, research impact, and products of lasting value, and perspectives for continued development of perovskite tandem solar cells. Research results in this dissertation have been reported through the associated publications.[1–20]