Rapid in situ photochemical synthesis of carbon dots in polymer coating by infrared CO2 laser writing for color tunable fluorescent patterning

Yuanyuan Guo, Yixun Gao, Yao Wang*, Yi Kuen Lee, Patrick J. French, Ahmad M. Umar Siddiqui, Hao Li, Guofu Zhou

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

The significant in situ multicolored patterning without changing printing tools nor substrate media still remains challenging, especially toward practical applications for anti-counterfeiting. This research invented a unique universal approach for the laser-induced in situ synthesis of colorful fluorescent patterns (from blue: CIE 0.15, 0.18 to red orange: CIE 0.36, 0.39) through the controlled formation of N, S doped carbon dots (CDs) in solid composite polymer films or hydrogel with a hierarchical and physically unclonable microsurface architecture for anti-counterfeiting. The in situ patterning approach, coupled with multi-layer technique, yielding designable blue, yellow, orange, and red orange color under 365 nm in the same pattern. A 5 cm2 colorful pattern can be efficiently finished within 5 min without changing the substrate and the line width accuracy can be up to 300 μm. The absolute quantum efficiency of the blue pattern reached as high as 23%. The fluorescent patterns can be survived at indoor for 24 months. The hydrogen bonding interactions between the CDs precursor and polymer facilitated the generation, uniform dispersion and stabilization of CDs during the laser irradiation. The hypothesis that laser irradiation induced photochemical reactions of CD precursors within a polymer matrix was supported by thermodynamic assessments. The universality of in situ fluorescent patterning strategy was demonstrated by developing fluorescent patterns on both solid polymer films, hydrogel, pharmaceutical packaging and textile.

Original languageEnglish
Article number158749
Number of pages12
JournalChemical Engineering Journal
Volume504
DOIs
Publication statusPublished - 2025

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Keywords

  • Anti-counterfeiting
  • Carbon dots
  • CO laser writing
  • Colorful fluorescent pattern
  • In situ photothermal reaction

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