Perovskite solar cells (PSCs) have experienced significant advancements, achieving unprecedented performance in terms of both cell efficiency and stability. To address the global energy challenge, it is crucial not only to improve efficiency but also to establish a scalable and environmentally friendly PSC industry. This requires a deep, fundamental understanding of the materials and a rational approach to their design. In this dissertation, I focused on modulating perovskite microstructures to enhance charge transport in PSCs.First, I investigated charge dynamics in perovskite materials, using perovskite quantum dots (PeQDs) as a model system. I analyzed carrier dynamics in coupled PeQD solids. Upon photoactivation, charge carriers can form polarons, which exhibit long carrier lifetimes, slow cooling rates, and extended diffusion lengths. Understanding these photophysical phenomena is critical for establishing the structure-property-performance relationship and correlating the grain size of perovskite crystals with charge collection efficiency. Building on this, I demonstrated an ion-assisted ligand exchange strategy to improve electronic coupling in PeQD solids. This method enabled the complete replacement of insulating surface ligands, resulting in compact, oriented packing and effective passivation of interfacial defects. As a result, this approach significantly enhanced the photocurrent gain of PSCs, improving overall cell performance. More importantly, PeQD-based PSCs exhibited exceptional stability due to thermodynamically stabilized phases, showing great potential for long-term stable PSCs. Next, I focused on tin-based perovskites, a promising emerging class of perovskite materials. I presented a cohesive ’bulk-to-interface’ strategy that combines composition and process co-design to facilitate the spontaneous formation of tin perovskite heterojunctions. By modulating spin time, ligand-separated multiple quantum wells can form beneath the bulk tin perovskite crystals. Using advanced characterization techniques such as grazing-incidence wide-angle X-ray scattering (GIWAXS) and transient absorption spectroscopy (TAS), I uncovered a ’diffusion-propagation’ mechanism that governs crystal formation. This approach resulted in tin perovskites with a ’3D-over-2D’ heterostructure, which promoted a favorable cascading band energy alignment and significantly reduces the photovoltage deficit. Finally, I envisioned the future of the perovskite industry, emphasizing scalability and sustainability. I discussed the optimal cell architectures, perovskite compositions, and deposition techniques necessary for developing a scalable and sustainable PSC industry, providing insights into how these innovations could help drive the widespread adoption of perovskite solar technology.