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Kaczmarek A., Wisniewska A.♦, Mościcki T. P., Hoffman J., The Luminescence of Laser-Produced Carbon Nanodots: The Effect of Aggregation in PEI Solution,
Materials, ISSN: 1996-1944, DOI: 10.3390/ma17071573, Vol.17, No.7, pp.1-15, 2024 Abstract:
Carbon nanodots (CNDs) produced in pure water by the ablation of graphite with a nanosecond laser pulse exhibit weak photoluminescence. A small addition of polyethyleneimine (PEI) to the aqueous suspension of CNDs causes a significant increase in emissions. This paper presents experimental and theoretical studies of the emission properties of CND/PEI systems. The obtained CNDs responded to even trace amounts of PEI in solution (~0.014% v/v), resulting in a significant increase in the initial weak blue emission of CNDs and PEI taken separately. Morphology and size measurements showed that particle aggregation occurred in the presence of the polymer. A decrease in the calculated Stokes shift values was observed with increasing PEI content in the solution. This indicates a reduction in the number of non-radiative transitions, which explains the increase in the emission intensity of the CND/PEI systems. These results therefore confirmed that the increase in the emission of CND/PEI systems is caused by particle aggregation. Kinetic studies proved that the process is controlled mainly by diffusion, the initial stage of which has a dominant influence on determining the optical properties of the system. Keywords:
aggregation-induced emission, carbon nanodots, polyethyleneimine, intrinsic fluorescence, adsorption kinetic study Affiliations:
| Kaczmarek A. | - | IPPT PAN | | Wisniewska A. | - | other affiliation | | Mościcki T. P. | - | IPPT PAN | | Hoffman J. | - | IPPT PAN |
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