# Host–Guest Engineering of MOF-808 for Random Lasing and Solid-State Emission

## TL;DR

This paper shows how embedding fluorescent dyes in MOF-808 improves their stability and enables efficient random lasing and solid-state emission.

## Contribution

The novel contribution is demonstrating MOF-808's dual role in preventing dye quenching and enhancing random lasing performance.

## Key findings

- MOF-808 prevents aggregation-caused quenching in dyes, enabling solid-state emission.
- MOF-808 nanoparticles act as efficient scatterers, enhancing random lasing with reduced thresholds.
- MOF-808-dye thin films are suitable for portable lasing applications with halved lasing thresholds.

## Abstract

Fluorescent organic dyes have a broad range of applications
across
various fields. However, their use is threatened by stability issues
such as photobleaching and aggregation-caused quenching that prevent
them from showing solid-state luminescence and being used in high-power
photonics applications for a long period. One possibility to overcome
these problems is to embed dye molecules within a hosting platform.
Metal–organic frameworks (MOFs) are among the best candidates
to overcome these problems due to their porous nature, which provides
excellent sorption capacities while ensuring stability for potential
guest molecules, even in extreme environments. In this work, we investigate
the optical performance of rhodamine B and coumarin 343 when interacting
with Zr-based MOF-808. On one hand, we demonstrate that inclusion
of dye molecules in MOF-808 cavities prevents aggregation-induced
quenching, enabling the use of dyes in powdered form and enhancing
their emission in solid-state applications, such as fingerprint detection.
On the other hand, the dye–MOF interaction in solution reveals
that MOF-808 nanoparticles act as efficient scatterers, significantly
enhancing random lasing emission by narrowing the emission spectra
and reducing the lasing threshold. The lasing performance is shown
to be dependent on the MOF concentration and excitation intensity,
with an optimal concentration minimizing the threshold and bandwidth.
Finally, we demonstrate the feasibility of combining MOF-808 nanoparticles
and dyes into polymeric thin films, where the MOFs contribute to halving
the lasing threshold, making the system suitable for portable lasing
applications.