Ligand-Mediated, Temperature-Tuned Synthesis of CsPbBr3 Nanosheets for Ordered Superlattice Assembly

TL;DR

Scientists developed a new method to create perovskite nanosheets with precise control over their size and structure, leading to better performance in optoelectronic devices.

Contribution

A modified ligand-assisted hot-injection strategy enables controlled synthesis of CsPbBr3 nanosheets with tunable optical properties and ordered superlattice assembly.

Findings

Nanosheets with thicknesses of 3.35 ± 0.05 nm and 4.05 ± 0.09 nm were produced at 130 and 140 °C, respectively.

Superlattices showed tunable photoluminescence peaks at 462, 464, and 513 nm with decay times ranging from 8.65 to 35.49 ns.

Ordered superlattices preserved intrinsic emission properties, indicating structural stability and scalability.

Abstract

Two-dimensional (2D) colloidal CsPbBr3 nanosheets (NSs) possess size-dependent optoelectronic properties; however, conventional hot-injection methods often lack precise growth control and well-ordered superlattice self-assembly. Herein, we introduce a modified ligand-assisted hot-injection strategy that promotes direct precursor–ligand interactions prior to solvent mixing, thereby enabling highly controlled nanosheet superlattice growth. By adjusting the reaction temperature from 130 to 150 °C, we obtained rectangular nanosheets with monodisperse, well-defined thicknesses of 3.35 ± 0.05 nm and 4.05 ± 0.09 nm at 130 and 140 °C, respectively, both below the 7 nm exciton Bohr diameter, consistent with strong quantum confinement. The resulting superlattices exhibited sharp, tunable photoluminescence peaks at 462, 464, and 513 nm, with time-resolved PL revealing a clear size–lifetime correlation, where smaller lateral superlattices at 130 °C showed a short decay time of 8.65 ns, intermediate growth at 140 °C yielded 15.42 ns, and larger lateral superlattices at 150 °C reached 35.49 ns. Importantly, the modified synthesis facilitated the formation of ordered superlattices that preserved their intrinsic emission properties, underscoring their structural stability and scalability. These findings establish a direct link between ligand-mediated synthesis, reaction temperature, nanosheet dimensions, and optical performance, offering a pathway to high-quality perovskite NS superlattices for advanced optoelectronic applications such as light-emitting diodes and sensors.

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