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Room temperature phosphorescence carbon dots (RTP CDs) are one of the newly investigated nanomaterials because of their remarkable optical characteristics. They are widely utilized in many versatile optoelectronic and security applications. Apart from synthesis, one of its challenging attributes is its lifetime at room temperature. Here, a straightforward and quick heating approach is presented for synthesizing self‐matrix 1,10 phenanthroline and boron‐based RTP CDs. 1,10 phenanthroline is utilized as an aromatic and hetero atom containing carbon precursor and boric acid is used as a passivating to stabilize the triplet excitons and prevent nonradiative deactivation. Various characterization techniques like TEM, XRD, FTIR, UV–vis, PL, and elemental analysis (ICP and CHNS) have been used to study the properties of self‐matrix RTP CDs. The RTP CDs exhibited excellent blue‐green emission when excited at 302 nm. Compared to the available literature, the novelty of this work is observed from its high naked eye phosphorescence characteristic of ≈22 s with an average lifetime of ≈ 2.4 s at 302 nm, making them ultralong self‐matrix RTP CD material. Due to their exceptional qualities, the self‐matrix RTP CDs have been widely employed for various applications, including information encryption decryption, phosphor for LEDs, anticounterfeiting, and water sensitivity analysis. [ABSTRACT FROM AUTHOR]

The development of flexible, lightweight, and thin high-performance electromagnetic interference shielding materials is urgently needed for the protection of humans, the environment, and electronic devices against electromagnetic radiation. To achieve this, the spinel ferrite nanoparticles CoFe 2 O 4 (CZ1), Co 0.67 Zn 0.33 Fe 2 O 4 (CZ2), and Co 0.33 Zn 0.67 Fe 2 O 4 (CZ3) were prepared by the sonochemical synthesis method. Further, these prepared spinel ferrite nanoparticles and reduced graphene oxide (rGO) were embedded in a thermoplastic polyurethane (TPU) matrix. The maximum electromagnetic interference (EMI) total shielding effectiveness (SE T ) values in the frequency range 8.2-12.4 GHz of these nanocomposites with a thickness of only 0.8 mm were 48.3, 61.8, and 67.8 dB for CZ1-rGO-TPU, CZ2-rGO-TPU, and CZ3-rGO-TPU, respectively. The high-performance electromagnetic interference shielding characteristics of the CZ3-rGO-TPU nanocomposite stem from dipole and interfacial polarization, conduction loss, multiple scattering, eddy current effect, natural resonance, high attenuation constant, and impedance matching. The optimized CZ3-rGO-TPU nanocomposite can be a potential candidate as a lightweight, flexible, thin, and high-performance electromagnetic interference shielding material., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)