Carbon dots(CDs)are light-emitting nanoparticles that show great promise for applications in biology and medicine due to the ease of fabrication,biocompatibility,and attractive optical properties.Optical chirality,on the other hand,is an intrinsic feature inherent in many objects in nature,and it can play an important role in the formation of artificial complexes based on CDs that are implemented for enantiomer recognition,site-specific bonding,etc.We employed a one-step hydrothermal synthesis to produce chiral CDs from the commonly used precursors citric acid and ethylenediamine together with a set of different chiral precursors,namely,L-isomers of cysteine,glutathione,phenylglycine,and tryptophan.The resulting CDs consisted of O,N-doped(and also S-doped,in some cases)carbonized cores with surfaces rich in amide and hydroxyl groups;they exhibited high photoluminescence quantum yields reaching 57％,chiral optical signals in the UV and visible spectral regions,and two-photon absorption.Chiral signals of CDs were rather complex and originated from a combination of the chiral precursors attached to the CD surface,hybridization of lower-energy levels of chiral chromophores formed within CDs,and intrinsic chirality of the CD cores.Using DFT analysis,we showed how incorporation of the chiral precursors at the optical centers induced a strong response in their circular dichroism spectra.The optical characteristics of these CDs,which can easily be dispersed in solvents of different polarities,remained stable during pH changes in the environment and after UV exposure for more than 400 min,which opens a wide range of bio-applications.

Ananya Das;Evgeny V.Kundelev;Anna A.Vedernikova;Sergei A.Cherevkov;Denis V.Danilov;Aleksandra V.Koroleva;Evgeniy V.Zhizhin;Anton N.Tsypkin;Aleksandr P.Litvin;Alexander V.Baranov;Anatoly V.Fedorov;Elena V.Ushakova;Andrey L.Rogach

Center of Information Optical Technologies,ITMO University,Saint Petersburg 197101,Russia;Research Park,Saint Petersburg State University,Saint Petersburg 199034,Russia;Laboratory of Femtosecond Optics and Femtotechnology,ITMO University,Saint Petersburg 197101,Russia;Laboratory of Quantum Processes and Measurements,ITMO University,Saint Petersburg 197101,Russia;Department of Materials Science and Engineering,and Centre for Functional Photonics(CFP),City University of Hong Kong,Kowloon,Hong Kong SAR 999077,China;Shenzhen Research Institute,City University of Hong Kong,Shenzhen 518057,China

光：科学与应用（英文版）

[1]Ananya Das;Evgeny V.Kundelev;Anna A.Vedernikova;Sergei A.Cherevkov;Denis V.Danilov;Aleksandra V.Koroleva;Evgeniy V.Zhizhin;Anton N.Tsypkin;Aleksandr P.Litvin;Alexander V.Baranov;Anatoly V.Fedorov;Elena V.Ushakova;Andrey L.Rogach-.Revealing the nature of optical activity in carbon dots produced from different chiral precursor molecules)[J].光：科学与应用（英文版）,2022(05):855-867

phenylglycine

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