MXene Quantum Dots as Multifunctional Interfacial Modulators for High-Performance Perovskite Solar Cells

Abstract

MXene quantum dots (MQDs), as zero-dimensional derivatives of two-dimensional transition metal carbides/nitrides, have emerged as versatile nanomaterials for enhancing perovskite solar cell (PSC) performance. 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, bandalignment 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 current understanding and provides a comprehensive perspective on the mechanistic, structural, and device-level impacts of MQDs, representing the first systematic review focused on MQDs in PSCs.