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Hydrothermal synthesis of carbon quantum dots (CQDs) from biomass is a green and sustainable route for CQDs applications in various fields. However, one of the major problems is the low CQDs yield because the traditional hydrothermal treatment would produce large amounts of hydrochar byproduct. In this work, we present a novel, facile, and effective method for large-scale synthesis of CQDs from biomass-derived carbon including hydrochar and carbonized biomass through mild oxidation (NaOH/H2O2 solution). An ultrahigh CQDs yield of 76.9 wt % can be obtained, which is much higher than those obtained from traditional hydrothermal and strong acid oxidation processes. Furthermore, the CQDs have excellent quantum yield (QY) that is higher than (or comparable to) those from other methods. In addition, the CQDs have uniform size (∼2.4 nm) and their surface states can be regulated to significantly improve the QY by adjusting the concentration of oxidants. The CQDs displayed excellent sensitivity for Pb2+ detection along with good linear correlation ranging from 1.3 to 106.7 μM. These advantages, together with low cost, sustainability, and green process, make this approach have great potential in the synthesis and applications of CQDs in large scale.

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Two organic sensitisers 4-biphenylcarboxylate (BPC) and terephthalate (TA) were intercalated into the gallery of layered europium hydroxide (LEuH). PL spectra tests indicated that BPC markedly enhanced the red luminescence of Eu(3+) due to efficient energy transfer between BPC and Eu(3+), forming a contrast to intercalated TA and the starting NO(3)(-) anions in the gallery. The energy level matching of the organic guests and Eu(3+) was also discussed to explain the energy transfer from sensitiser to Eu(3+).

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It is recognized that an effective strategy to promote the industrialization of supercapacitors is to enhance the ion and electronic conductivities of electrode materials.

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Cationic conjugated polymers (CCPs) have attracted more and more attention in antibacteria and tumor treatment based on photodynamic therapy (PDT). However, the main chain structure−antibacterial activities relationship has been rarely reported. Herein, we designed and synthesized four cationic conjugated polymers: one poly(fluorine phenylene) derivative (PFP) and three poly(fluorene-co-phenylene ethynylene) derivatives (PFE-1, PFE-CN-2, and PFE-NP-3). PFP and PFE-1 have the same side chains but bear different conjugated backbones. PFE-CN-2 (π-A) and PFE-NP-3 (A-π-A) are modified with electron-donating and/or electron-withdrawing groups. Three PFEs can produce reactive oxygen species (ROS) faster than PFP. The order of antibacterial activities of the four CCPs is as follows: PFE-CN-2 > PFE-1 ≫ PFE-NP-3 ≈ PFP, which is coincident with the generation rate of ROS. In addition, CCPs with D-π-A structure is more advantageous than A-π-A in ROS production and in antibacterial performance. These results provide an important base for designing more efficient PDT agents for antibacteria and antitumor.