Assembling ultra-small nanoparticles into nanosized colloidal nanocrystal clusters (CNCs) to create novel collective properties still poses tremendous challenges. This work reports the fabrication of photoluminescent CdTe CNCs on the nanoscale and their thermo-responsive properties. Diblock copolymers of poly(N-(2-aminoethyl) acrylamide-b-N-isopropylacrylamide) (PNAEAM-b-PNIPAM) were synthesized and employed as self-assembling actuators of CNCs. The side chains of PNAEAM blocks act as efficient anchors to capture CdTe nanocrystals via surface ligand identification. The thermo-sensitive PNIPAM blocks serve as the protection layer of CNCs and the trigger to turn off/on the photoluminescence CNCs during heating/cooling cycles. The [HS–C10mim]+ ligands with smart noncovalent interactions on the as-prepared nanocrystals render the CNCs rapid and reversible thermo-response performances. These make the CNCs an excellent thermo-responser, and offer a new controllable self-assembly route for designing and engineering multifunctional nanosized CNCs.

Thiol-functionalized dialkylimidazolium bromide was synthesized, and used as a stabilizer to prepare monodisperse silver nanocrystals through a facile one-pot aqueous approach. It is shown that the multipurpose ligands play a vital role in improving the performance of nanocrystals. The mechanisms of dialkylimidazolium-mediated promotion were analyzed on the basis of the physicochemical properties of the specifically designed ligand.

High fluorescence efficiency is desired for the practical applications of semiconductor nanocrystals (NCs) in many fields. However, reducing photoluminescence (PL) efficiency is usually observed after ligand exchanges on nanocrystal surfaces due to the generation of surface defects. Here, we report the preparation of polyvinylpyrrolidone-capped CdSe NCs (CdSe/PVP), and show the PL enhancement of CdSe/PVP NCs under UV radiation in the air. The experimental results indicate that the PL-enhanced mechanism of the NCs in methanol results from passivation of the lyates in that they act as the hole-acceptors. By screening of hole scavenger, furthermore, it is found that ditertbutyl peroxide is a better passivators of surface defects, and promotes the PL efficiency of CdSe/PVP NCs to achieve a value 110 times higher than that of as-prepared CdSe/PVP NCs. The photopassivation in the presence of organic molecules provides a prefertial, inexpensive path to harvest NCs with high PL efficiency.Highlights► PL efficiency is promoted by photoactivation in all dispersion media. ► MeO− plays a very important role in the exceptional PL enhancement. ► Ditertbutyl peroxide can act as much better passivator of surface traps than MeO−.

The dependences of the absorption spectra of chrome azurol S (CAS) and Al3+–CAS complexes on the concentration of ionic liquids (ILs), 1-alkyl-3-methylimidazolium bromide ([CnMim]Br, with n = 8, 10, 12), were measured at 298.15 K in aqueous solutions with pH = 5.6. It is found that ILs can induce the significant red-shifts of the wavelength at the absorption maximum (λmax) of Al3+–CAS complex from 545 to 646 nm for [C8Mim]Br, and to 642 nm for [C12Mim]Br and [C16Mim]Br, respectively. Accompanying the red-shifts, the absorbance at λmax, and thereby molar absorptivity (ɛ), changes markedly with the IL concentration, and consequently the effect of ILs on the absorbance at λmax is systematically investigated in this work. Along with the experimental results of resonance light scattering, the sensitization mechanism is analyzed from the aggregation of the ILs and the interactions of ILs with CAS and Al3+–CAS complexes. It is shown that the hydrophobic interactions of IL subaggregates with CAS in Al3+–CAS complex are the crucial factor for the sensitization.

Surface modification of metal nanostructures can create multifunctional materials potentially very useful in many application fields and, consequently, has been the subject of intensive studies. This work reported the modification of silver nanoparticles (Ag NPs) by UV-induced interface reactions, a method controllable in both the color and the surface chemistry of the nanoparticles. Using poly(N-vinyl-2-pyrrolidone) (PVP) as the protecting polymer, Ag NPs were synthesized in ethanol and then mixed with α-bromoisobutyric acid (BIBA). When the mixture is exposed to UV irradiation, Ag NPs present themselves in a serial tone from pale blue to blue, dark blue, and finally purple with the progress of the interface reactions. It is shown that these color changes are directly related to the chemical components on the surface of Ag NPs, and hence the correlation of the colors with the chemical states of main components on the surface of Ag NPs has been made during the course of interface reactions.

The polymer–ammonium complexes are an important class of proton conducting polymer electrolytes. In this work, poly(ethylene oxide) (PEO)–NH4SCN electrolytes were prepared over a large range of the salt content, and their FT-IR spectra were measured at room temperature. Based on the assignments of each band in the spectral envelope of SCN−1, their relative intensities are determined by the use of FT-IR technique. Following the experimental results and spectral analyses, this paper reports the interactions, the various ionic associations, the changes of the ionic association with NH4SCN content, and the characteristics of structure in PEO–NH4SCN electrolytes. It is shown that the hydrogen bonds of PEO and NH4SCN exert the great effect to the ionic association, the interactions of PEO with NH4SCN, and PEO crystallinity, in particular, under the condition of high NH4SCN content. In addition, the differences of ionic association among PEO–NaSCN, PEO–KSCN and NH4SCN electrolytes are also compared in this paper.

Thiol-functionalized dialkylimidazolium bromide was synthesized, and used as a stabilizer to prepare monodisperse silver nanocrystals through a facile one-pot aqueous approach. It is shown that the multipurpose ligands play a vital role in improving the performance of nanocrystals. The mechanisms of dialkylimidazolium-mediated promotion were analyzed on the basis of the physicochemical properties of the specifically designed ligand.