Sensitized Lanthanide Photoluminescence Based Sensors–a Review

Abstract

Photoluminescent supramolecular systems such as hydrogels and metal‐organic frameworks (MOFs) can be useful for applications in many areas. In aqueous media, lanthanides exhibit luminescence by sensitization through covalently linked chromophores (antenna effect), making them valuable for sensing and imaging applications. Fluorescent sensing by sensitized lanthanide emission in gels and MOFs provides a simple and rapid detection of analytes with high sensitivity and selectivity. This review presents the gradual evolution and the intriguing conceptualization of sensitized luminescence of lanthanides spanning the sensing of biomolecules, drugs, small organic molecules and enzymes employing hydrogels or MOFs as the sensing platform.

Regulating the luminescence of tetraphenylethene (TPE)-based lanthanide nanoparticles in the presence of organic amines/acids

“…38 In this system, the energy gap Δ E 2 is 1762 cm −1 (TPE-motif to Eu 3+ ) and 3766 cm −1 (ABM to Eu 3+ ). Since the Δ E 2 value for an effective sensitizer must be higher than 3500 cm −1 according to the antenna effect, 39–42 the TPE-motif cannot light up the luminescence of Eu 3+ as effectively as ABM in TPE-Py-Me@PSS/ABM@EuVO 4 nanoparticles (Fig. 3).…”

Modular Assembly of Isostructural Mixed-Ligand Uranyl Coordination Polymers Based on a Patterning Strategy

“…Coordination polymers (CPs) that are constructed from organic linkers and inorganic building blocks have attracted a great deal of interest in recent years because of their potential for the rational design of crystal structures and functional properties, which have shown good application prospects in many fields, − including proton conduction, catalysis, gas separation and storage, magnetic materials, fluorescent sensing, etc. The structural designability endows strands of coordination polymers with profound physicochemical properties.…”

Metal–Organic Framework with Near-Infrared Luminescence for “Switch-on” Determination of Kaempferol and Quercetin by the Antenna Effect

“…Luminescent metal–organic frameworks combined the intrinsic photophysical property and porosity for the encapsulation of guest molecules, and the obtained guest@MOFs could act as platforms for host–guest interaction studies . In particular, lanthanide-based MOFs (Ln-MOFs) have attracted extensive attention owing to their excellent optical performance, such as large stokes shifts, high quantum yields, narrow full width at half maximum (FWHM), and long lifetime, along with a wide emission range from ultraviolet (UV) to near-infrared (NIR), , However, the molar absorption coefficients of lanthanide ions (Ln 3+ ions) are usually small (<10 L mol –1 cm –1 ) because of the ″forbidden” f-f electronic transitions . Consequently, the strong emission of Ln 3+ ions can be achieved through a process called sensitization or the antenna effect .…”

“…In particular, lanthanide-based MOFs (Ln-MOFs) have attracted extensive attention owing to their excellent optical performance, such as large stokes shifts, high quantum yields, narrow full width at half maximum (FWHM), and long lifetime, along with a wide emission range from ultraviolet (UV) to near-infrared (NIR), , However, the molar absorption coefficients of lanthanide ions (Ln 3+ ions) are usually small (<10 L mol –1 cm –1 ) because of the ″forbidden” f-f electronic transitions . Consequently, the strong emission of Ln 3+ ions can be achieved through a process called sensitization or the antenna effect . Thus, organic linkers or guest molecules can absorb photons, then energy can be transferred from the triplet state to accepting electronic levels of Ln 3+ ions, , which is beneficial to build fluorescence sensors with the “switch-on” model.…”

“…41 Consequently, the strong emission of Ln 3+ ions can be achieved through a process called sensitization or the antenna effect. 41 Thus, organic linkers or guest molecules can absorb photons, then energy can be transferred from the triplet state to accepting electronic levels of Ln 3+ ions, 42,43 which is beneficial to build fluorescence sensors with the "switch-on" model. In addition, considering deeper tissue penetration and lower tissue lethality of NIR light, 44,45 the luminescence of Ln-MOFs in the NIR spectral range is a great breakthrough in materials science and biology.…”