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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]

In this work, the microwave-assisted synthesis of manganese metal–organic framework (MOF) material is presented. Synthesis procedure is based on a microwave-assisted solvothermal reaction of manganese(III) acetylacetonate with biphenyl-4,4′-dicarboxylic acid (Bpdc) in N,N′-dimethylformamide at the temperature of 160 °C. The obtained Mn-based metal–organic framework, labeled as Mn-Bpdc, was used as a precursor for the preparation of a porous MnO/carbon nanocomposite, which was obtained via thermal transformation in a nitrogen atmosphere at 700 °C. It was found that this approach provides an effective and simple preparation pathway for porous carbon decorated with homogeneously embedded manganese(II) oxide nanoparticles. Both Mn-Bpdc and MnO/C nanocomposite materials were characterized by a variety of physicochemical methods. The prepared MnO/C nanocomposite material was deposited on a cathode surface of lithium-sulfur batteries and utilized as a shuttle suppressing layer. This electrode structure immobilizes polysulfides inside the cathode and improves the stability during cycling. The electrode with MnO/C nanocomposite shuttle suppressing layer maintains high stability during cycling in comparison with a standard electrode. The electrode with MnO/C composite layer exhibits 84.8% capacity retention after 50 cycles at different C-rates compared to 76.2% obtained for the standard electrode. [ABSTRACT FROM AUTHOR]

In this work, vanadium metal-organic framework derived VO x /carbon and VO x /N-doped carbon nanocomposites are presented. The methodology introduced here is based on a novel polyol synthesis of vanadium metal-organic frameworks (MOFs) involving a microwave-assisted solvothermal reaction of vanadyl acetylacetonate with biphenyl-4,4′-dicarboxylic acid (Bpdc) and/or 2,2′-bipyridine-4,4′-dicarboxylic acid (NBpdc) in diethylene glycol (DEG) at the temperature of 230 °C. The V-based MOFs, labeled as V-Bpdc and V-NBpdc, were used as precursors for the preparation of VO x /carbon and VO x /N-doped carbon nanocomposites with unique sponge-like nano-sheet and paperclip-like morphology, respectively. The nanocomposites were obtained via thermal transformation of as-prepared vanadium MOFs in the argon atmosphere at 600 °C. The VO x /carbon sample consists of nano-sheets with the thickness 5–20 nm while the VO x /N-doped carbon paperclip-like nanocomposite has a rod diameter 35–70 nm. It was found that the approach reported here provides an effective and simple preparation pathway of carbon-based nanocomposites containing homogeneously distributed VO x species. Both V-MOFs and V-MOF-derived nanocomposites were characterized by the variety of physicochemical methods. In the following step, the obtained nanocomposites were investigated as electrode materials in sodium-ion batteries. Based on the obtained results, high electrochemical activities of VO x /carbon and VO x /N-doped carbon nanocomposites were evidenced. Particularly, in the case of VO x /N-doped carbon-based electrode, high capacity and low irreversible capacity were achieved. Therefore, reported materials are found to be promising candidates for electrode materials in sodium-ion batteries. [Display omitted] • Novel microwave-assisted polyol synthesis of vanadium MOF materials introduced. • Original nano-sheet and paperclip morphologies of V-MOF derived nanocomposites. • VO x /Carbon and VO x /nitrogen-doped carbon successfully utilized in Na-ion batteries. • Improved electrochemical behavior of VO x /N-doped carbon due to nitrogen doping. • Low irreversible capacity and high performance V-MOF derived nanocomposites observed. [ABSTRACT FROM AUTHOR]