Strategic Defect Passivation in Two-Dimensional Halide Perovskite Field-Effect Transistors via Molecular Engineering

Recent advancements in metal halide perovskites (MHPs) have spotlighted their exceptional electronic and optoelectronic characteristics, positioning them as promising candidates for next-generation device applications. Despite their potential, the deployment of MHPs in practical applications is significantly impeded by concerns regarding lead toxicity and material stability. In response to these challenges, the exploration of lead-free alternatives, particularly tin-based perovskite materials such as PEA₂SnI₄ , has emerged as a viable pathway. These materials not only exhibit intrinsic p-doping properties but also demonstrate enhanced stability relative to their three-dimensional counterparts, making them suitable for application in p-type field-effect transistors (FETs). However, the practical application of tin-based perovskites is complicated by inherent issues such as self-oxidation and ion migration along grain boundaries, which adversely affect their electronic properties. To address these challenges, this study investigates the use of phosphine oxide based Lewis base small molecules for the defect passivation of tin-based perovskites, aiming to elucidate the underlying mechanisms and improve the performance of FETs fabricated from these materials [3]. Through this approach, we have successfully optimized the transistor performance, achieving an enhanced average hole mobility of 1.9 cm²/Vs, with peak values reaching up to 2.2 cm²/Vs. This research not only provides a deeper understanding of the defect passivation mechanisms in tin-based perovskites but also paves the way for the development of advanced electronic devices leveraging halide-perovskite materials.

References
[1] Zhu, H. et al. “High-Performance and Reliable Lead-Free Layered-Perovskite Transistors” Adv Mater 32, 2002717 (2020)
[2] Matsushima, T. et al. “Toward air-stable field-effect transistors with a tin iodide-based hybrid perovskite semiconductor.” J Appl Phys 125, 235501 (2019)
[3] H. Choi, K. Kang* et al (In preparation)