Specific locations of blue and green-emitting units in dual emissive carbon dots and their reversible emitting properties due to switchable inter-chromophoric interactions

• Published in: Journal of colloid and interface science Vol. 605; pp. 364 - 372
• Main Authors: Bhuyan, Rahul, Bramhaiah, Kommula, Bhattacharyya, Santanu
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-01-2022
• Subjects: And Thermoresponsive photoluminescence; Dual emissive Carbon dots; Polarized emission; Time-resolved area normalized emission spectroscopy; Polarized emission; Dual emissive Carbon dots; And Thermoresponsive photoluminescence; Time-resolved area normalized emission spectroscopy
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2021.07.119

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Carbon dots (CDs) are the unique class of luminescent nanomaterials consist of various chromophoric units heterogeneously distributed throughout the nanoparticle, resulting intriguing multistate emissive properties. Herein, we have critically investigated the specific locations of the blue and green-emitting centers inside dual emissive CDs by steady-state and time-resolved polarized emission study. It is further clarified by a temperature-dependent fluorescence study for both the emitting domains. Results suggest that the blue chromophoric units are located at the interior part of CDs, while green units are mostly at the exterior region. Furthermore, we have investigated the solvent-dependent inter-chromophoric interactions between the two emissive domains by the Time-Resolved Area Normalized Emission Spectroscopy (TRANES). Results suggest that at polar aprotic solvent acetone, time-dependent positive evolution of green-emitting states and negative evolution of blue emissive domains have been observed. This reversible emitting properties evolve due to the excited state energy migration from blue emissive domains to green emissive domains at polar aprotic medium, while in the case of polar protic solvent water, this phenomenon is missing. This switchable inter-chromophoric interaction are correlated further with the inter-particle interactions of CDs.