Engineering Metal Halide Perovskites for High-Performance Light-Emitting Diodes and Field-Effect Transistors

Metal halide perovskites are emerging as a revolutionary class of semiconductors due to their unique combination of outstanding optical and electronic properties and their versatility in low-temperature synthesis and substrate compatibility. In this talk I will focus on the development and optimization of perovskite-based light-emitting diodes (PeLEDs) and transistors. For PeLEDs, a vapor-based acetate methylamine (FAAc) treatment has been introduced to address the challenges associated with halide vacancy defects in blue-emitting PeLEDs. The innovative approach mitigates solvent-induced damage during the typical post-deposition process, ensuring a controlled and uniform incorporation of halide ions into the perovskite lattice. The study reveals the superior performance of F-PEAX treatment over conventional organic salts, resulting in blue-emitting PeLEDs with peak external quantum efficiencies (EQEs) of 19.28%, 11.55%, and 7.28% at emission peaks of 483 nm, 474 nm, and 465 nm, respectively. These devices also exhibit narrow full-width at half-maximum (FWHM) electroluminescence, making them ideal for high-definition display applications. Additionally, I will discuss the advancements in tin halide perovskite (THP) transistors. Our development of a one-step vapor-processing method for phase-pure CsSnI3 thin films overcomes the limitations of traditional solution-processed THPs. This method achieves wafer-size uniform films with high crystallinity and low defect density, enabling the fabrication of high-performance transistors with field-effect hole mobility exceeding 30 cm²V^-1s^-1, on/off current ratios over 10⁸, and excellent operational stability. These findings demonstrate the potential of CsSnI₃ transistors for scalable and cost-effective production, paving the way for their integration into complementary circuits alongside n-type oxide-based transistors.