Binding of CsPbBr₃ Nanocrystals to MOF-5 for the Detection of Cadmium Ions in Aqueous Media

Abstract

CsPbBr 3 perovskite nanocrystals (CNCs) have emerged as promising candidates for optoelectronics, although instability issues have retarded their progress toward commercialization. As a solution to this core issue, herein CNCs are bound to the metal−organic framework MOF-5 to form a stable composite MOF:CNC for sensing applications in aqueous media. The electrostatic interaction of Pb 2+ and Br − ions of CNCs with the terephthalate and Zn 2+ ions of MOF-5 do not disturb the structural integrity of the MOFs and the photoluminescence (PL) properties of the CNCs but renders more stability to both the MOFs and CNCs in a water medium. As a proof-of-concept experiment, this water-resistant MOF:CNC probe was successfully validated for the detection of Cd 2+ in a water medium. The mechanism of fluorescence enhancement during the sensing of Cd 2+ is elucidated using X-ray photoelectron spectroscopy, temperature-dependent, and time-resolved PL studies. The high stability and photoefficiency exhibited by this MOF:CNC composite proves that it is a viable system for applications in aqueous media.

Fluorescence Quenching Detection of Clothianidin in Fruit and Vegetable Samples Using MAPbBr3 Perovskite Quantum Dots

“…Metal halide perovskite quantum dots (PQDs) exhibit high absorption, high photoluminescence quantum yield (PL QY), small full-width-half-maximum (fwhm), high crystallinity, and superior photostability and are defect-tolerant compared to other fluorescent probes . PQDs have been successfully applied in the detection of cadmium ions, ethanolamine, pesticides, etc. However, due to their intrinsic ionic nature, PQDs are chemically unstable and the perovskite structure can be damaged by humidity and ambient temperature .…”

CsPbBr3 NCs Confined and In Situ Grown in ZIF-8: A Stable, Sensitive, Reliable Fluorescent Sensor for Evaluating the Acid Value of Edible Oils

“…Numerous researches make a point that the stability of halide perovskites can be improved by passivating surface defects or reducing contact with the external surroundings. − In this context, several strategies have been proposed to improve the stability of halide perovskites, including surface encapsulation, ligand modification, metal doping, etc. ,, Regarding the surface encapsulation, halide perovskites could be confined and grown in metal–organic frameworks (MOFs) (such as MOF-5, MOF-808, Pb-MOF, etc.) to improve stability. − MOFs, as a kind of porous crystal materials, are composed of inorganic metal ions or clusters and organic ligands connected by coordination bonds with high surface area and porosity, adjustable pore structure, and ease of synthesis . Herein, zeolitic imidazolate framework-8 (ZIF-8), as one of the most typical MOFs, has been widely used in gas separation, catalysis, and sensing due to excellent stability, open metal sites, etc. − There have been studies on the combination of ZIF-8 with CsPbBr 3 NCs. , Zhao et al used a mechanical grinding method to synthesize stable CsPbBr 3 @ZIF-8 for light-emitting diode and optoelectronic device applications .…”