ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

One-pot green synthesis of blue light-emitting carbon dots using seaweed Halimeda opuntia and their photoluminescent properties

Sekaran Muthamil Selvan, Kabali Vijai Anand, Kasivelu Govindaraju, Gandhirajan Vinitha, Ashok K. Sundramoorthy, Kalimuthu Raja, and Manoharan Latha

Department of Physics, Sathyabama Institute of Science and Technology, Chennai, India

E-mail: anandkvijai78@gmail.com

Received: 28 June 2024  Accepted: 3 February 2026

Abstract:

In the present study, fluorescent carbon dots (CDs) have been bioengineered using seaweed Halimeda opuntia through an eco-friendly hydrothermal approach and reported here for the first time. The physicochemical properties of CDs were analysed using XRD, FT-IR, TEM-EDAX, UV-VIS, PL, Raman and Z-scan studies. From XRD pattern the broad diffraction peak at 2θ = 24.31^° confirms the occurrence of amorphous carbon with a graphite-like structure. The optical absorption studies confirmed the presence of π- π* electron transfer of the conjugate C =C due to the absorption peak at around 260 nm. FTIR analysis showed the presence of functional groups which are responsible for the formation of CDs using Halimeda opuntia seaweed. From Z – scan analysis, the nonlinear optical (NLO) properties of CDs were studied.

Keywords: Biomass extract; Carbon dots; Halimeda opuntia; Photoluminescent; Nonlinear optical

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04720-w

Chemical Papers 80 (5) 5407–5413 (2026)