Blue-emitting nitrogen-doped carbon dots (CDN) produced by a solvent-free method have been successfully incorporated into silica (SiO2) through a sol-gel procedure. By exploiting the co-gelation of the dispersed carbon dots and of the silica matrix, homogeneous distribution of the carbon dots was obtained throughout the matrix. The CDN-SiO2 composites in the form of xero-, cryo-, and aerogels featuring different porous textures were produced by exploiting different gel drying strategies. The most critical parameters and the material features associated to the different synthesis were investigated by transmission electron microscopy, thermal analysis, Mid-infrared spectroscopy, N2 physisorption isotherms and time-resolved spectrofluorimetry. The emissive properties of CDN-SiO2 composites in the form of aero-, cryo- and xerogel were studied. The spectral properties and the efficiency of the emission change in the CDN-SiO2 composites pointed at the effect of CD loading and porous texture of xerogels. Our investigation expands the exploitation of functional carbon dots through the production of fluorescent solid-state composites with tunable porosities.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The financial support of Università di Cagliari and Fondazione di Sardegna, project ADVANCING, CUP F74I19001030007 and project NG-Light, CUP F74I19000930007 and Italian Ministry of Education, University and Research (MIUR) project PRIN2017 “CANDL2” (Grant 2017W75RAE), are gratefully acknowledged. SVT thanks financial support under P.O.R. Sardegna F.S.E.-Operational Programme of the Autonomous Region of Sardinia, European Social Fund 2014-2020- Axis III Education and training, Thematic goal 10, Investment Priority 10ii- Specific goal 10.5.12. We acknowledge the CeSAR (Centro Servizi Ricerca d'Ateneo) core facility of the University of Cagliari and Dr. A. Ardu for assistance with the generation of TEM images on a Jeol JEM 1400 Plus microscope.