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Nano Research

Article Title

High brightness NIR-II nanofluorophores based on fused-ring acceptor molecules

Authors

Xingfu Zhu, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China
Chunchen Liu, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China
Zhubin Hu, State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
Haile Liu, Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300350, China
Jiang Wang, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China
Yang Wang, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China
Xinyuan Wang, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China
Rui Ma, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China
Xiaodong Zhang, Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300350, China
Haitao Sun, State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
Yongye Liang, Department of Materials Science and Engineering, Shenzhen Key Laboratory of Printed Organic Electronic, Southern University of Science and Technology, Shenzhen 518055, China

Keywords

nanofluorophores, fused-ring acceptor, propylenedioxy thiophene, high brightness, second near-infrared (NIR-II) biological imaging

Abstract

It is challenging to develop molecular fluorophores in the second near-infrared (NIR-II) window with long wavelength emission and high brightness, which can improve the performance of biological imaging. Herein, we report a molecular engineering approach to afford NIR-II fluorophores with these merits based on fused-ring acceptor (FRA) molecules. Dioctyl 3,4-propylenedioxy thiophene (PDOT-C8) is utilized as the bridging donor to replace 3-ethylhexyloxy thiophene (3-EHOT), leading to more than 20 times enhancement of brightness. The nanofluorophores (NFs) based on the optimized CPTIC-4F molecule exhibit an emission peak of 1,110 nm with a fluorescence quantum yield (QY) of 0.39% (QY of IR-26 is 0.050% in dichloroethane as reference) and peak absorption coefficient of 14.5 × 104 M−1·cm−1 in aqueous solutions, which are significantly higher than those of 3-EHOT based COTIC-4F NFs. It is found that PDOT-C8 can weaken intermolecular aggregation, enhance protection of molecular backbone from water, and decrease backbone distortion, beneficial for the high brightness. Compared with indocyanine green with same injection dose, CPTIC-4F NFs show 10 times higher signal-to-background ratio for whole body vessels imaging at 1,300 nm long pass filters.

Graphical Abstract

Publisher

Tsinghua University Press

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