Journal Home > Volume 16 , Issue 3

Deep-red and near-infrared emissive carbon dots (CDs) are highly desired for bioimaging, especially in deep tissue imaging, but they are extremely rare and the known ones usually suffer from low-efficient fluorescence in water and aggregation-induced fluorescence quenching in solid state. In this work, CDs with intriguing solvent-dependent and two-photon fluorescence emissions have been prepared by a facile solvothermal method. Detailed characterizations reveal that there is an n→π* interaction between the carboxyl functional groups on CDs and the electron donor groups in solvent, which leads to the increase of energy density of CDs and the decrease of energy level, resulting in the red shift of luminescence with enhanced electron donating ability of solvent. Inspired by this finding, mesoporous silica nanoparticles (MSNs) with suitable pore size and low biological toxicity are modified by amino groups to confine CDs, thus the deep-red fluorescence emission is achieved both in solid state and in water facilitated by the n→π* interaction of host–guest. The as-prepared CDs@EDA-MSN composite exhibits high-efficient fluorescence with 650 nm wavelength, low toxicity, and good biocompatibility, which endow them a promising application in bio-imaging.

File
12274_2022_4829_MOESM1_ESM.pdf (611 KB)
Publication history
Copyright
Acknowledgements

Publication history

Received: 30 June 2022
Revised: 26 July 2022
Accepted: 27 July 2022
Published: 22 August 2022
Issue date: March 2023

Copyright

© Tsinghua University Press 2022

Acknowledgements

Acknowledgements

The authors thank the financial supports by the National Natural Science Foundation of China (Nos. 21920102005, 21835002, and 21621001) and the 111 Project of China (No. B17020).

Return