Carbonized Polymer Dots with Controllable N, O Functional Groups as Electrolyte Additives to Achieve Stable Li Metal Batteries.

Electrolyte additive is an effective strategy to inhibit the uncontrolled growth of Li dendrites for lithium metal batteries (LMBs). However, most of the additives are complex synthesis and prone to decompose in cycling. Herein, in order to guide the homogeneous deposition of Li+ , carbonized polymer dots (CPDs) as electrolyte additives are successfully designed and synthesized by microwave (M-CPDs) and hydrothermal (H-CPDs) approaches. The controllable functional groups containing N or O (especially pyridinic-N, pyrrolic-N, and carboxyl group) enable CPDs to keep stable in electrolytes for at least 3 months. Meanwhile, the clusters formed between CPDs and Li+ through electrostatic interaction effectively guide the uniform Li dispersion and limit the "tip effect" and dendrite formation. Moreover, as lithiophilic groups increase, the strong electrostatic interference for the solvation effect of Li+ in the electrolyte is formed, which induces faster Li+ diffusion/transfer. As expected, H-CPDs achieve the ultra-even Li+ transfer. The corresponding Li//LiFePO4 full cell delivers a high capacity retention rate of 93.8% after 200 cycles, which is much higher than that of the cells without additives (61.2%) and with M-CPDs (83.7%) as additives. The strategy in this work provides a theoretical direction for CPDs as electrolyte additives used in energy storage devices.

Multiple Resonance Dendrimers Containing Boron, Oxygen, Nitrogen-Doped Polycyclic Aromatic Emitters for Narrowband Blue-Emitting Solution-Processed OLEDs.

In contrast to small-molecule multiple resonance emitters processed via vacuum evaporation technology, the design of multiple resonance dendrimers is presented by introducing the first- and second-generation carbazole dendrons in the periphery of boron, oxygen, nitrogen-doped polycyclic aromatic skeleton, for efficient narrowband blue electroluminescence by a solution process. The multiple resonance dendrimers not only keep the narrowband emission of the polycyclic aromatic skeleton, but also can suppress their intermolecular aggregation by steric carbazole dendrons, overcoming the unwanted spectral broadening in the solid state. The resultant first-generation carbazole dendrimer exhibits narrowband blue emission with promising photoluminescent quantum efficiency of 94% and delayed fluorescence with a lifetime of 139.1 µs in the solid-state film. Solution-processed organic light-emitting diodes based on the dendrimers reveal electroluminescence at 488 nm with full-width at half maximum of 39 nm, the maximum luminous efficiency of 29.2 cd A-1 , and maximum external quantum efficiency of 13.4%.

In-situ formation of nanosized 1T-phase MoS2 in B-doped carbon nitride for high efficient visible-light-driven H2 production.

The high photogenerated carrier recombination rate and the low visible light utilization limit the development of graphitic carbon nitride (CN) in industrial photocatalytic H2 generation. Herein, 1T-phase MoS2 nanoparticles with high conductivity and more active sites are in-situ grown on B-doped carbon nitride (CNB) nanosheets through a one-step hydrothermal method. The doping of boron element effectively improves the harvesting visible light ability by tuning the energy gap, while the introduction of 1T-phase MoS2 successfully increases the carrier transfer rate by suppressing charge trapping. An optimized H2 production activity of 5334 µmol h-1 g-1 with the apparent quantum efficiency of 10.2% is achieved by 1T-MoS2/CNB sample, which is 167 times higher than that of pure CN. The mechanism is systematically illustrated by the combination of DFT calculations and transient absorption measurements. This work provides a new way for the construction of transition metal-derived co-catalysts in photocatalytic hydrogen energy storage.

Judicious design functionalized 3D-COF to enhance CO2 adsorption and separation.

The effects of functional groups (including OH, OCH3 , NH2 , CH2 NH2 , COOH, SO3 H, OCO(CH2 )2 COOH(E-COOH), and (CH2 )4 COOH(c-COOH)) in 3D covalent organic frameworks (3D-COFs) on CO2 adsorption and separation are investigated by grand canonical Monte Carlo (GCMC) simulations and density functional theory calculations. The results indicate that interaction between CO2 and the framework is the main factor for determining CO2 uptakes at low pressure, while pore size becomes the decisive factor at high pressure. The binding energy of CO2 with functionalized linker is correlated to CO2 uptake at 0.3 bar and 298 K on 3D-COF-1, suggesting functional groups play a key role in CO2 capture in microporous 3D-COFs. Moreover, CO2 selectivity over CH4 , N2 , and H2 can be significantly enhanced by functionalization, where CH2 NH2 , COOH, SO3 H, and E-COOH enhance CO2 adsorption more effectively at 1 bar. Among them, SO3 H is the most promising functional group in 3D-COFs for CO2 separation.

Water-soluble polymer functionalized CdTe/ZnS quantum dots: a facile ratiometric fluorescent probe for sensitive and selective detection of nitroaromatic explosives.

A ratiometric fluorescent probe based on dual luminescence QD/CPL for selective sensing of the nitroaromatic explosive picric acid (PA) was constructed. The observed ratiometric fluorescence intensity change allows the quantitative detection of PA with a detection limit of 9 nM.

A facile strategy to fabricate thermoresponsive polymer functionalized CdTe/ZnS quantum dots: assemblies and optical properties.

Novel thermoresponsive CdTe/ZnS quantum dots (QDs) decorated with a copolymer ligand (CPL) containing 8-hydroxyquinoline and NIPAM units are prepared through coordinate bonding in aqueous solution. The dependence of the morphology and optical properties of the QDs/CPL assemblies formed via coordinate bonding on the experimental conditions is studied. The coordinate induced self-assemblies are observed by controlling the molar ratio of QDs and CPL. The self-organized structure of QDs/CPL proceeds through a first step of QDs-chains, followed by a necklace-like single annular chain, and subsequently increases its annular chain structure, forming a network. The CPL functionalized QDs can emit multiple colors from the cooperating interaction between the inherent emission (606 nm) of the QDs and the surface-coordinated emission (517 nm) of the CPL complex formed on the QD surface. For QDs-CPL systems, both Förster resonance energy transfer (FRET) and a high rate of photoinduced electron transfer (PET) are simultaneous, the latter mainly contributing to PL quenching. The thermoresponsive QDs/CPL assemblies also exhibit dual reversible PL properties between the inherent emission of QDs and surface-coordinated emission.

Carbon quantum dots enhance the photocatalytic performance of BiVO4 with different exposed facets.

Carbon quantum dots (CQDs) were demonstrated to have the ability to enhance the photocatalytic performance of monoclinic BiVO4 with different exposed facets under visible light.