Confinement of Sustainable Carbon Dots Results in Long Afterglow Emitters and Photocatalyst for Radical Photopolymerization

Ping Wang; Min Ge; Xiongfei Luo; Yingxiang Zhai; Nicolai Meckbach; Veronika Strehmel; Shujun Li; Zhijun Chen; Bernd Strehmel

doi:10.1002/anie.202402915

Confinement of Sustainable Carbon Dots Results in Long Afterglow Emitters and Photocatalyst for Radical Photopolymerization

Angew Chem Int Ed Engl. 2024 Apr 3:e202402915. doi: 10.1002/anie.202402915. Online ahead of print.

Authors

Ping Wang¹, Min Ge², Xiongfei Luo¹, Yingxiang Zhai¹, Nicolai Meckbach³, Veronika Strehmel³, Shujun Li¹, Zhijun Chen¹, Bernd Strehmel⁴

Affiliations

¹ Northeast Forestry University, Key Laboratory of Bio-based Material Science and Technology of Ministry of Education, CHINA.
² Northeast Forestry University, Key Laboratory of Bio-based Material Science and Technology of Ministry of Education, CHILE.
³ Niederrhein University of Applied Sciences, Chemistry, GERMANY.
⁴ Niederrhein University of Applied Sciences, Department of Chemistry, Coatings and New Materials, Adlerstr. 1, 47798, Krefeld, GERMANY.

PMID: 38569128
DOI: 10.1002/anie.202402915

Abstract

Sustainable carbon dots based on cellulose, particularly carboxymethyl cellulose (CMCCDs), were confined in an inorganic network resulting in CMCCDs@SiO2. This resulted in a material exhibiting long afterglow covering a time frame of several seconds also under air. Temperature-dependent emission spectra gave information on temperature-assisted delayed fluorescence (TADF) and room temperature phosphorescence (RTP) while photocurrent experiments provided a deeper understanding of charge availability in the dark period, and therefore, its availability on the photocatalyst surface. The photo-ATRP initiator, ethyl(bromo)phenyl acetate (EBPA), quenched the emission from the millisecond to the nanosecond time frame indicating participation of the triplet state in photoinduced electron transfer (PET). Both free radical and living radical polymerization based on photo-ATRP protocol worked successfully. Metal-free photo-ATRP resulted in chain extendable macroinitiators based on a reductive mechanism with either MMA or in combination with styrene. Addition of 9 ppm Cu2+ resulted in Mw/Mn of 1.4 while an increase to 72 ppm improved uniformity of the polymers; that is Mw/Mn=1.03. Complementary experiments with kerria laca confined materials, namely KCDs@SiO2, provided similar results. Deposition of Cu2+ (9 ppm) on the photocatalyst surface explains better uniformity of the polymers formed in the ATRP protocol.

Keywords: Sustainable Carbon Dot Confinement Long Afterglow Photopolymerization.