A new design for second near-infrared window (NIR-II) molecular fluorophores based on a shielding unit-donor-acceptor-donor-shielding unit (S-D-A-D-S) structure is reported. With 3,4-ethylenedioxy thiophene as the donor and fluorene as the shielding unit, the best performance fluorophores IR-FE and IR-FEP exhibit an emission quantum yield of 31% in toluene and 2.0% in water, respectively, representing the brightest organic dyes in NIR-II region reported so far.

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Uniform single-crystalline PbTe nanowires with average diameter of about 30 nm, below its average excitonic Bohr radius of 46 nm, were successfully synthesized in large quantity by a two-step hydrothermal process using tellurium nanowires as templates and Pb(NO3)2 as a precursor. It is shown that the reaction temperature, duration, and concentration of Pb(NO3)2 play important roles in the formation of the PbTe nanowires. An in situ diffusion and growth mechanism together with a nontopotactic transformation process was proposed to explain the formation of the PbTe nanowires. The thermoelectric transport measurement indicates a high Seebeck coefficient of about 628 μV/K in the thin film sample composed of the obtained PbTe nanowires, about 137% exceeding that of the state-of-the-art bulk PbTe. The calculated local density of states (LDOS) by the density functional theory shows a strong increase with decreasing nanowire diameter, which is consistent with the measured large enhancement in Seebeck coefficient in the PbTe nanowire sample.

The study mainly investigated the synergetic adsorption of hydrogen bonding and hydrophobic interaction. To simplify the adsorption driving forces and binding sites, the hydrophilic and hydrophobic microdomain was introduced onto polypropylene (PP) nonwoven. The amphiphilic structure was constructed for the adsorption of bisphenol A (BPA). A solvent shielding experiment was conducted to calculate the contributions of diverse interactions. Also, a specific structure without hydrophilic microdomain was constructed as comparison to determine the adsorption rate and quantify the diffusion behaviors. On the basis of double-exponential model, the adsorption process can be distinctly divided into three stages, namely film diffusion stage, intralayer diffusion stage, and dynamic equilibrium stage. The adsorption rate was dramatically improved due to the influence of hydrophilic microdomain and participation of hydrogen bonding adsorption. Discussions on adsorption priority were also proposed. The results of surface energy heterogeneity revealed that the hydrophilic microdomain or the hydrogen bonding site was occupied preferentially.