Tunable Fluorescein-Encapsulated Zeolitic Imidazolate Framework-8 Nanoparticles for Solid-State Lighting

TL;DR

This paper reports the fabrication of fluorescein-encapsulated ZIF-8 nanoparticles with high quantum yield and enhanced photostability, demonstrating their potential for tunable solid-state lighting and optical applications.

Contribution

The study introduces a scalable method for encapsulating fluorescein in ZIF-8 nanoparticles, achieving high quantum yield and improved photostability for solid-state lighting.

Findings

Quantum yield of ~98% in solid state

Enhanced photostability due to nanoconfinement

Demonstrated multicolor and white light emission

Abstract

A series of fluorescein-encapsulated zeolitic imidazolate framework-8 (fluorescein@ZIF-8) luminescent nanoparticles with a scalable guest loading has been fabricated and characterized. The successful encapsulation of the organic dye (fluorescein) is supported by both experimental evidence and theoretical simulations. The measured optical band gap is found to be comparable with the computed values of a hypothetical guest-host system. Isolated monomers and aggregates species of fluorescein confined in ZIF-8 nanocrystals have been systematically investigated through fluorescence lifetime spectroscopy. The quantum yield (QY) of the obtained solid-state materials is particularly high (QY~98%), especially when the concentration of the fluorescein guest is low. Combining a blue LED chip and a thin photoactive film of fluorescein@ZIF-8, we demonstrate a device with good optical tunability for multicolor and white light emissions. Additionally, we show that the fluorescein@ZIF-8 nanoparticles exhibit an improved photostability due to the shielding effect conferred by the nanoconfinement of host framework, making them promising candidates for practical applications such as solid-state lighting, photonics, and optical communications.