Synthesis of organic-inorganic perovskite and all-inorganic lead-free double perovskite nanocrystals by femtosecond laser pulses

TL;DR

This paper introduces a ligand-free femtosecond laser ablation method to synthesize high-purity perovskite nanocrystals with tunable optical properties, advancing scalable fabrication for optoelectronic applications.

Contribution

The study presents a novel, ligand-free femtosecond laser ablation technique for synthesizing high-purity perovskite nanocrystals without stabilizing ligands, applicable to both hybrid and inorganic double perovskites.

Findings

Successfully synthesized ligand-free perovskite nanocrystals with controlled sizes.

Demonstrated size-dependent optical property tuning via quantum confinement.

Achieved high crystallinity and purity in nanocrystals across different compositions.

Abstract

Perovskite materials are at the forefront of modern materials science due to their exceptional structural, electronic, and optical properties. The controlled fabrication of perovskite nanostructures is crucial for enhancing their performance, stability, and scalability, directly impacting their applications in next-generation devices such as solar cells, LEDs, and sensors. Here, we present a novel, ligand-free approach to synthesize perovskite nanocrystals (NCs) with average sizes up to 100 nm, using femtosecond pulsed laser ablation (PLA) in ambient air without additional liquid media. We demonstrate this method for both organic-inorganic (methylamino lead) hybrid perovskites (MAPbX3, X = Cl, Br, I) and fully inorganic lead-free double perovskites (Cs2AgBiX6, X = Cl, Br), achieving high-purity NCs without stabilizing ligands - a critical advancement over conventional chemical synthesis methods. By tailoring laser parameters, we systematically elucidate the influence of perovskite composition (halide type, organic vs. inorganic cation, single versus double perovskite structure) on the ablation process and the resulting nanocrystal properties. Transmission electron microscopy and X-ray diffraction confirm the preservation of crystallinity, with MAPbX3 forming larger (approximately 90 nm) cubic NCs and Cs2AgBiX6 forming smaller (approximately 10 nm) rounded NCs. Photoluminescence spectroscopy reveals pronounced size-dependent blue shifts (17-40 nm) due to quantum confinement, particularly for Br and I containing perovskites. This clean, scalable, and versatile PLA approach not only provides direct access to high-purity, ligand-free perovskite NCs with tunable optical properties but also represents a significant advance in the fabrication of nanostructures, enabling the exploration of new perovskite-based optoelectronic and quantum devices.