MXene quantum dots as multifunctional interfacial modulators for high-performance perovskite solar cells

Abstract

MXene quantum dots (MQDs) are zero-dimensional derivatives of MXenes with unique physicochemical properties. Owing to their tunable surface chemistry, excellent conductivity, and abundant functional groups, MQDs have emerged as promising materials for perovskite solar cells (PSCs). Their unique combination of tunable surface chemistry, high electrical conductivity, and quantum-confined electronic properties enables multifunctional roles at interfaces and within perovskite films. MQDs can simultaneously act as defect passivators, band-alignment modulators, crystallization directors, and localized charge transport facilitators, collectively improving power conversion efficiency, reducing hysteresis, and enhancing operational stability. Incorporation strategies include integration into electron transport layers (ETLs), hole transport layers (HTLs), and perovskite precursors, where MQDs regulate nucleation and growth, optimize energy-level offsets, and mitigate interfacial recombination. Mechanistic studies reveal that surface terminations such as –O, –OH, –F, and –Cl are critical for achieving these multifunctional effects. Despite significant progress, challenges remain in scalable synthesis, controlled functionalization, and large-area device integration, particularly for flexible and tandem PSC architectures. Future directions involve combinatorial approaches that couple precise MQD design, advanced characterization, and computational modeling to fully exploit their potential. This review consolidates the current understanding of MQDs and provides a comprehensive perspective on their mechanistic, structural, and device-level impacts in PSCs. To the best of our knowledge, it is among the few reviews specifically focused on the roles of MQDs in PSCs, with particular emphasis on their integration pathways, interfacial functions, and effects on photovoltaic performance and stability.