Highly Luminescent Ag–In–Zn–S Quaternary Nanocrystals: Growth Mechanism and Surface Chemistry Elucidation
Piotr Bujak , Zbigniew Wróbel , Mateusz Penkala , Kamil Kotwica , Angelika Kmita , M. Gajewska , Andrzej Ostrowski , Patrycja Kowalik , Adam Proń
AbstractThe presented research is focused on the synthesis of alloyed Ag–In–Zn–S colloidal nanocrystals from a mixture of simple metal precursors such as AgNO3, InCl3, zinc stearate combined with 1-dodecanethiol (DDT), 1-octadecene (ODE), and sulfur dissolved in oleylamine (OLA). In particular, the focus is on the effect of the solvent (ODE vs 1,2-dichlorobenzene (DCB)) and the type of sulfur precursor (S/OLA vs S/n-octylamine (OCA)) on the metal precursors reactivates and on the chemical composition, crystal structure, and luminescent properties of the resulting nanocrystals. The replacement of ODE by DCB as a solvent lowers the reactivity of metal precursors and results in a 3-fold decrease of the photoluminescence quantum yields (Q.Y.) values (from 67% to 21%). This negative effect can be fully compensated by the use of S/OCA as a source of sulfur instead of S/OLA (Q.Y. increases from 21% to 64%). NMR studies of the isolated organic phase indicate that the S/OLA precursor generates two types of ligands being products of (Z)-1-amino-9-octadecene (OLA) hydrogenation. These are “surface bound” 1-aminooctadecane (C18H37NH2) and crystal bound, i.e., alkyl chain covalently bound to the nanocrystal surface via surfacial sulfur (C18H37-NH-S crystal). Highly luminescent Ag–In–Zn–S nanocrystals exhibit a cation-enriched (predominantly indium) surface and are stabilized by a 1-aminooctadecane ligand, which shows more flexibility than OLA. These investigations were completed by hydrophilization of nanocrystals obtained via exchange of the primary ligands for 11-mercaptoundecanoic acid, (MUA) with only a 2-fold decrease of photoluminescence Q.Y. in the most successful case (from 67% to 31%). Finally, through ligand exchange, an electroactive inorganic/organic hybrid was obtained, namely, Ag–In–Zn–S/7-octyloxyphenazine-2-thiol, in which its organic part fully retained its electrochemical activity.
|Journal series||Inorganic Chemistry, ISSN 0020-1669, (A 40 pkt)|
|Publication size in sheets||0.6|
|Score||= 40.0, 25-07-2019, ArticleFromJournal|
|Publication indicators||: 2016 = 1.198; : 2017 = 4.7 (2) - 2017=4.513 (5)|
|Citation count*||2 (2019-08-03)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.