Indium(II) Chloride as a Precursor in the Synthesis of Ternary (Ag–In–S) and Quaternary (Ag–In–Zn–S) Nanocrystals

Abstract

A new indium precursor, namely, indium(II) chloride, was tested as a precursor in the synthesis of ternary Ag−In−S and quaternary Ag−In−Zn−S nanocrystals. This new precursor, being in fact a dimer of Cl 2 In−InCl 2 chemical structure, is significantly more reactive than InCl 3 , typically used in the preparation of these types of nanocrystals. This was evidenced by carrying out comparative syntheses under the same reaction conditions using these two indium precursors in combination with the same silver (AgNO 3 ) and zinc (zinc stearate) precursors. In particular, the use of indium(II) chloride in combination with low concentrations of the zinc precursor yielded spherical-shaped (D = 3.7−6.2 nm) Ag−In−Zn−S nanocrystals, whereas for higher concentrations of this precursor, rodlike nanoparticles (L = 9−10 nm) were obtained. In all cases, the resulting nanocrystals were enriched in indium (In/Ag = 1.5−10.3). Enhanced indium precursor conversion and formation of anisotropic, longitudinal nanoparticles were closely related to the presence of thiocarboxylic acid type of ligands in the reaction mixture. These ligands were generated in situ and subsequently bound to surfacial In(III) cations in the growing nanocrystals. The use of the new precursor of enhanced reactivity facilitated precise tuning of the photoluminescence color of the resulting nanocrystals in the spectral range from ca. 730 to 530 nm with photoluminescence quantum yield (PLQY) varying from 20 to 40%. The fabricated Ag−In−S and Ag−In−Zn−S nanocrystals exhibited the longest, reported to date, photoluminescence lifetimes of ∼9.4 and ∼1.4 μs, respectively. It was also demonstrated for the first time that ternary (Ag−In− S) and quaternary (Ag−In−Zn−S) nanocrystals could be applied as efficient photocatalysts, active under visible light (green) illumination, in the reaction of aldehydes reduction to alcohols.

Influence of Hydrophilic Thiol Ligands of Varying Denticity on the Luminescence Properties and Colloidal Stability of Quaternary Semiconductor Nanocrystals

“…Typically, AIS-based QDs crystallize in a tetragonal, orthorhombic, and cubic phase, depending on the synthesis conditions and stoichiometry. ,− A wurtzite lattice is also possible, although it is relatively rare. This lattice is usually observed, e.g., for anisotropic ZnS–AgInS 2 QDs. , In our case, the symmetry and the calculated lattice plane distances (0.36 nm for {120}, 0.21 nm for {320}, and 0.18 nm for {400}) are in good agreement with previously published data on orthorhombic AIS QDs . Because the prepared ZAIS QDs can be regarded as solid solutions of AIS and ZnS phases, the pseudowurtzite-type crystal phase observed for our ZAIS QDs is ascribed to the small amount of Zn used in the synthesis of our nanoparticles.…”

“…62,63 In our case, the symmetry and the calculated lattice plane distances (0.36 nm for {120}, 0.21 nm for {320}, and 0.18 nm for {400}) are in good agreement with previously published data on orthorhombic AIS QDs. 64 Because the prepared ZAIS QDs can be regarded as solid solutions of AIS and ZnS phases, the pseudowurtzite-type crystal phase observed for our ZAIS QDs is ascribed to the small amount of Zn used in the synthesis of our nanoparticles. The elemental composition determined by EDX (Zn 0.03 Ag 0.9 In 1.18 S 1.89 ; see more details in Table S1) further supports the assumption of only a small amount of zinc being incorporated into the ZAIS QDs.…”

Near-infrared photoactive Ag-Zn-Ga-S-Se quantum dots for high-performance quantum dot-sensitized solar cells

“…The average mean diameter was found to be 5.11 nm and the spacing of one of the lattice fringes was observed to be 0.27 nm. This corresponds to the spacing distance of the (100) planes of hexagonal crystals [ 23 – 25 ]. The inset of Figure 2a shows the SAED pattern of the synthesized AZGSSe QDs.…”

A New Year and 35 Years of Chemistry of Materials

“…Our “35 Voices” initiative will also begin so that we may hear what motivates materials researchers from all over the world. To kick off our 35th year, however, we start by highlighting 35 of the most cited and downloaded manuscripts published in 2022. − …”

“…A useful Methods/Protocols article accompanies these contributions on best practices for the creation of perovskite solar cells . Luminescent and optical materials (Table ) − of all classes round-out the interest in sustainability, while also connecting to detector and sensor applications. Our list of 35 papers concludes with materials discovery (Table ), , which should push us to new frontiers.…”