Near-infrared fluorescent semiconducting polymer dots with high brightness and pronounced effect of positioning alkyl chains on the comonomers

Chuan Pin Chen, Ya Chi Huang, Sz Yu Liou, Pei Jing Wu, Shih Yu Kuo, Yang-Hsiang Chan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


In recent years, semiconducting polymer dots (Pdots) have emerged as a novel class of extraordinarily bright fluorescent probes with burgeoning applications in bioimaging and sensing. While the desire for near-infrared (NIR)-emitting agents for in vivo biological applications increases drastically, the direct synthesis of semiconducting polymers that can form Pdots with ultrahigh fluorescence brightness is extremely lacking due to the severe aggregation-caused quenching of the NIR chromophores in Pdots. Here we describe the synthesis of dithienylbenzoselenadiazole (DBS)-based NIR-fluorescing Pdots with ultrahigh brightness and excellent photostability. More importantly, the fluorescence quantum yields of these Pdots could be effectively increased by the introduction of long alkyl chains into the thiophene rings of DBS to significantly inhibit the aggregation-caused emission quenching. Additionally, these new series of DBS-based Pdots can be excited by a commonly used 488 nm laser and show a fluorescence quantum yield as high as 36% with a Stokes shift larger than 200 nm. Single-particle analysis indicates that the per-particle brightness of the Pdots is at least 2 times higher than that of the commercial quantum dot (Qdot705) under identical laser excitation and acquisition conditions. We also functionalized the Pdots with carboxylic acid groups and then linked biomolecules to Pdot surfaces to demonstrate their capability for specific cellular labeling without any noticeable nonspecific binding. Our results suggest that these DBS-based NIR-fluorescing Pdots will be very practical in various biological imaging and analytical applications.

Original languageEnglish
Pages (from-to)21585-21595
Number of pages11
JournalACS Applied Materials and Interfaces
Issue number23
StatePublished - 10 Dec 2014


  • conjugated polymer nanoparticles
  • conjugated polymers
  • dithienylbenzoselenadiazole
  • near-infrared fluorescence
  • semiconducting polymer dots
  • specific cellular labeling


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