Probing the emission dynamics in nitrogen-doped carbon dots by reversible capping with mercury(ii) through surface chemistry

0559778 - ÚFCH JH 2023 RIV GB eng J - Článek v odborném periodiku
Roy, D. - Das, A. - Roy, Rajarshi - Das, D. - Das, B. K. - Ghorai, U. K. - Chattopadhyay, K. K. - Sarkar, S.
Probing the emission dynamics in nitrogen-doped carbon dots by reversible capping with mercury(ii) through surface chemistry.
New Journal of Chemistry. Roč. 46, č. 30 (2022), s. 14690-14702. ISSN 1144-0546. E-ISSN 1369-9261
Institucionální podpora: RVO:61388955
Klíčová slova: Carbon * Chemical bonds * Doping (additives)
Obor OECD: Physical chemistry
Impakt faktor: 3.3, rok: 2022
Způsob publikování: Omezený přístup

In this study, the mechanistic insight and emission dynamics have been explored for size-dependent nitrogen-doped carbon quantum dots (namely 3A, 3B & 3C) with toxic metal Hg2+ ions via a capping and uncapping mechanism. The excitation and pH-dependent emission profile of N-CQDs is assigned to multiple centers involving higher energy aromatic core states (pi-pi*) and lower energy oxygen- and nitrogen-based functional groups (nO(2)p-pi* and nN(2)p-pi*). From experimental and theoretical validation, the highly negatively charged surface of 3A is found to be mainly due to the high abundance ofCOOH and NH2 groups promoting weak (COO-)(2)-Hg2+, NH2-Hg2+ bond formation with the reduction of the sp(2) carbon content with different concentrations of Hg2+ ions. Thus, the combined effect shrinks the P.L. signals (area and intensity) associated with the pi-pi* and n-pi* transitions through the static and dynamic quenching pathway (LOD similar to 0.209 mu M). Furthermore, the restoration of PLE and P.L. signals is carried out by uncapping Hg2+ ions. The high recovery percentage (similar to maximum96%) is mainly governed by COOH and NH2 groups rather than the deeply buried core state. Thus, the prominent reversible quenching associated with surface states is well supported by changes in zeta potential measurements. Our investigation demonstrates the direct dependence of surface chemistry on the proposed emission dynamics of carbon dots.
Trvalý link: https://hdl.handle.net/11104/0332979