Carbon Quantum Dots Meet Perovskite Solar Cells: A Review of Multifunctional Synergies

Perovskite solar cells (PSCs) have emerged as one of the most promising next-generation photovoltaic technologies owing to their remarkable power conversion efficiencies (PCEs), low fabrication costs, and tunable optoelectronic properties. However, their widespread adoption is still hampered by intrinsic instabilities and performance degradation caused by interfacial defects, poor film crystallinity, and sensitivity to environmental factors. In recent years, carbon-based dots have attracted significant attention as multifunctional additives and interfacial modifiers in PSC architectures. This review provides a comprehensive overview of the roles these nanomaterials play across various device layers, including the antisolvent treatment, hole and electron transport layers (HTL and ETL), active layer, and interfacial regions. Particular emphasis is placed on their capabilities in regulating crystallization, passivating defects, improving energy-level alignment, and enhancing moisture and thermal stability. Key studies are discussed chronologically, with a focus on their impact on device efficiency, long-term stability, and underlying mechanisms. Overall, the integration of carbon quantum dots offers a promising approach to overcoming the critical limitations of PSCs and advancing scalable, high-performance, and durable solar energy technologies.