Single Excited Dual Band Luminescent Hybrid Carbon Dots-Terbium Chelate Nanothermometer.

Rustem R Zairov,Alberto Vomiero,Asiya R Mustafina,Vladimir A Burilov,Svetlana N Sudakova,Andrey V Luzhetskiy,Ivan M Vatsouro,Kirill A Sarkanich,Irek R Nizameev,Sergey N Podyachev,Alexey P Dovzhenko

doi:10.3390/nano11113080

Abstract

The report introduces hybrid polyelectrolyte-stabilized colloids combining blue and green-emitting building blocks, which are citrate carbon dots (CDs) and [TbL]+ chelate complexes with 1,3-diketonate derivatives of calix[4]arene. The joint incorporation of green and blue-emitting blocks into the polysodium polystyrenesulfonate (PSS) aggregates is carried out through the solvent-exchange synthetic technique. The coordinative binding between Tb3+ centers and CD surface groups in initial DMF solutions both facilitates joint incorporation of [TbL]+ complexes and the CDs into the PSS-based nanobeads and affects fluorescence properties of [TbL]+ complexes and CDs, as well as their ability for temperature sensing. The variation of the synthetic conditions is represented herein as a tool for tuning the fluorescent response of the blue and green-emitting blocks upon heating and cooling. The revealed regularities enable developing either dual-band luminescent colloids for monitoring temperature changes within 25–50 °C through double color emission or transforming the colloids into ratiometric temperature sensors via simple concentration variation of [TbL]+ and CDs in the initial DMF solution. Novel hybrid carbon dots-terbium chelate PSS-based nanoplatform opens an avenue for a new generation of sensitive and customizable single excited dual-band nanothermometers.

Highlights

The wide diversity of organic and inorganic luminophores allows different mechanisms to generate luminescent responses on external stimuli to be applied, which results in a great diversity of sensing systems [1,2,3]
The synthesis of hybrid carbon dots-terbium chelate nanothermometer owning blue and green-emitting components into the PSS-based nanoplatform was performed through several steps: (1) synthesis of the components; (2) evaluation of their sensing ability to heating and cooling; (3) revealing of the binding between the components; (4) optimization of conditions for the combined incorporation of both components into the PSS-nanoplatform
Transmission electron microscopy (TEM) particle characterization showed that the dots are quasi-spherical monodisperse species with an average size of (2.3 ± 0.6) nm remaining erratically distributed on the substrate surface (Figure 2a)

Summary

Introduction

The wide diversity of organic and inorganic luminophores allows different mechanisms to generate luminescent responses on external stimuli to be applied, which results in a great diversity of sensing systems [1,2,3]. Photoluminescent carbon dots (CDs) have emerged as important materials in sensing and cell imaging [23,24] since the high surface charge of CDs results from the nature of the hydrophilic exterior layer and is predominantly constituted by chelating anions This is the reason for its high affinity to counter-ions, including metal ions [25,26]. Ln3+ -based species possessing narrow emission bands, large Stokes shift, and high emission quantum yields inspired many reports on Ln3+ -based thermometers with outstanding sensitivity, temperature resolution, and robustness in the last decade [31,32] In this regard, the implementation of Ln3+ -based materials to hybrid nanostructures is a budding strategy for the design of novel ratiometric nanothermometers. The variation of the concentration conditions will be introduced as a tool to control the mutual influence of the components on their sensing properties in order to develop colloids for temperature monitoring in the 25–50 ◦ C range through the differently emitting registration channels and to transform the colloids into ratiometric temperature sensors

Experimental Section

Results and Discussion

Conclusions