Meitang Liu

Assembly of luminescent ordered multilayer thin-films based on oppositely-charged MMT and magnetic NiFe-LDHs nanosheets with ultra-long lifetimes

In this present report, luminescent ordered multilayer thin films (OMFs) based on oppositely-charged inorganic nanosheets and the different oppositely-charged chromophores were fabricated via layer-by-layer assembly method. Exfoliated layered double hydroxides (LDHs) and montmorillonite (MMT) nanosheets with opposite charges can be expected to provide a pseudo electronic microenvironment (PEM) which has not been declared in previous literatures, and transition metal-bearing LDHs nanosheets can offer an additional ferromagnetic effect (FME) for the chromophores at the same time. Surprisingly, the luminescent lifetimes of those OMFs with PEM and FME are significantly prolonged compared with that of the pristine chromophores, even much longer than those of OMFs without oppositely-charged and ferromagnetic architecture. Therefore, it is highly expected that the PEM and FME formed by oppositely-charged and transition metal-bearing inorganic nanosheets have remarkable influence on obtaining better optical property, which suggests a new potential way to manipulate, control and develop the novel light-emitting materials and optical devices.

Facile Synthesis of Flower-Like Copper-Cobalt Sulfide as Binder-Free Faradaic Electrodes for Supercapacitors with Improved Electrochemical Properties

Supercapacitors have been one of the highest potential candidates for energy storage because of their significant advantages beyond rechargeable batteries in terms of large power density, short recharging time, and long cycle lifespan. In this work, Cu–Co sulfides with uniform flower-like structure have been successfully obtained via a traditional two-step hydrothermal method. The as-fabricated Cu–Co sulfide vulcanized from precursor (P–Cu–Co sulfide) is able to deliver superior specific capacitance of 592 F g−1 at 1 A g−1 and 518 F g−1 at 10 A g−1 which are surprisingly about 1.44 times and 2.39 times higher than those of Cu–Co oxide electrode, respectively. At the same time, excellent cycling stability of P–Cu–Co sulfide is indicated by 90.4% capacitance retention at high current density of 10 A g−1 after 3000 cycles. Because of the introduction of sulfur during the vulcanization process, these new developed sulfides can get more flexible structure and larger reaction surface area, and will own richer redox reaction sites between the interfaces of active material/electrolyte. The uniform flower-like P–Cu–Co sulfide electrode materials will have more potential alternatives for oxides electrode materials in the future.

Lifetime-ultra-prolonged luminescent multilayer thin films with electronic microenvironment

In this report, luminescent multilayer thin films (MTFs) based on functional molecules intercalated into layered double hydroxides (LDHs) and montmorillonite (MMT) nanosheets were fabricated by layer-by-layer assembly method (LBL method). Exfoliated LDHs and MMT nanosheets with opposite charges can be expected to provide an electronic microenvironment (EME) for chromophores, which are not found in previous literatures, and to offer the inorganic rigid building blocks at the same time. Surprisingly, the lifetimes of MTFs with EMEs architecture are significantly prolonged, compared with that of the pristine powder, even considerably longer than those of the MTFs without EMEs architecture. Therefore, it is highly expected that the EME formed by oppositely-charged inorganic nanosheets has remarkable influence on enhancing the lifetimes of chromophores, which suggests a new potential method to develop novel light-emitting materials and optical devices.

Molecular dynamics simulation of polylactic acid/ organoclay nanocomposites: Effects of different organic modifiers

A molecular dynamics study was performed to analyze the effects of different organic modifiers (OMs) on the atomic scale structure, binding energies and basal spacing of polylactic acid/organoclay nanocomposites. Each supercell comprising one molecule of polylactic acid (PLA), montmorillonite (MMT) with a cation exchange capacity (CEC) of 102mmol/100g organomodified with several quaternary alkylammonium ions (Quats) and two positively charged amino acids(arginine and lysine) was constructed during simulation tasks. According to the results, amino acids exhibit strong affinity to MMT surface and create considerable spacing room which is very important to intercalation procedure. In contrasting, ordinary Quats demonstrate weaker interaction with MMT unless they are carboxylic modified. This work gave an instructive suggestion for PLA nanocomposites preparation.

Synthesis and Characterization of La-Doped Luminescent Multilayer Films

In this work, we have successfully designed ordered luminescent multilayer films based on La-doped nonmagnetic or magnetic inorganic nanostructure with electronic microenvironment (EM). The inorganic nanosheets with opposite charge can assemble EM between the interlayers. At the same time, their elements on nanosheets of layer double hydroxides (LDHs) are facile to be replaced so that we can introduce transition metal or lanthanide elements. Besides, ferromagnetic effect (FE) can be formed in this microenvironment due to introducing transition metal on LDHs nanosheets. As a result, we confirm that EM, FE, and doping La element in the LDHs can affect the vibration of backbone of chromophores and then prolong the luminescent lifetime, which suggests a new pathway for developing the novel light-emitting thin films.

Theoretical analyzing of monomers adsorbing in nano-slits

A revised model based on Lattice-Density-Fuiiction Theory (LDFT) was built in this paper and was used to indicate the adsorbing behaviors of monomers in nano slits. This work tried to establish a theoretical model and get the fundamental mechanisms of the in situ-monomer-intercalation process which is the most common production method of polymer-layer silicate intercalated nanocomposite (PLSN). According to the results, the multilevel adsorption and 3D phase transition phenomenon in nano slits predicted by original LDFT do not exit in reality. They are probably aroused by system errors caused by simple mean field approximation treatments. The nano slits have obvious boundary effects on density profile distribution of monomers.