Brightly luminescent colloidal Ag–In–S nanoparticles stabilized in aqueous solutions by branched polyethyleneimine

Temperature‐Dependent Photoluminescence of Silver‐Indium‐Sulfide Nanocrystals in Aqueous Colloidal Solutions

“…[18,19,35] Such structure of the absorption spectra makes the assessment of the bandgap quite tricky and prohibits the evaluation of the thermally-induced shifts in the absorption/PL excitation spectra of ternary NCs. At the same time, we argued [16] that the broadband PL of AIS NCs can be described by a model of self-trapped excitons implying the PL band position to be directly dependent on the bandgap energy and, therefore, the changes of the PL band maximum energy can be taken as directly reflecting the temperatureinduced changes of the bandgap of AIS NCs.…”

“…[23,24] In these studies, we found that luminescent properties of aqueous ultra-small CdX NCs and ternary AIS (CIS) NCs are very similar, both types of NCs emitting relatively intense visible PL characterized by large spectral widths and Stokes shifts. [16,[18][19][20][21][22][23] We found also that the ultra-small CdS NCs stabilized by Cd(II) complexes with PEI or NH 3 /MA reveal unusually strong temperature dependences of both absorption edge and PL intensity when probed in aqueous colloidal solutions, [21,22] showing a peculiar PL quenching mechanism differing from that typical for "regular" CdX NCs capped by covalently bound ligands. [25][26][27][28][29][30][31] In the present work we explore the variations of PL parameters of GSH-capped AIS (AIS/ZnS) NCs produced directly in aqueous solutions in the temperature window of 10-80°C in comparison with previously studied ultra-small CdX NCs capped with Cd(II) complexes.…”

“…In particular, we reported recently on the aqueous syntheses of ternary AIS and core/shell AIS/ZnS NCs stabilized by NC surface complexes with polyethyleneimine (PEI), thioglycolic (mercaptoacetic) acid, and glutathione (GSH) . Our approaches to aqueous ternary NCs stemmed from our previous works on the syntheses of ultra‐small (the size d <2nm) CdS NCs capped with Cd(II) complexes with polyethyleneimine (PEI) or mixed complexes of Cd(II) with ammonia and mercaptoacetate (MA), as well as ultra‐small core/shell CdSe/CdS NCs .…”

“…Our approaches to aqueous ternary NCs stemmed from our previous works on the syntheses of ultra‐small (the size d <2nm) CdS NCs capped with Cd(II) complexes with polyethyleneimine (PEI) or mixed complexes of Cd(II) with ammonia and mercaptoacetate (MA), as well as ultra‐small core/shell CdSe/CdS NCs . In these studies, we found that luminescent properties of aqueous ultra‐small CdX NCs and ternary AIS (CIS) NCs are very similar, both types of NCs emitting relatively intense visible PL characterized by large spectral widths and Stokes shifts . We found also that the ultra‐small CdS NCs stabilized by Cd(II) complexes with PEI or NH 3 /MA reveal unusually strong temperature dependences of both absorption edge and PL intensity when probed in aqueous colloidal solutions, showing a peculiar PL quenching mechanism differing from that typical for “regular” CdX NCs capped by covalently bound ligands …”

Spontaneous alloying of ultrasmall non-stoichiometric Ag–In–S and Cu–In–S quantum dots in aqueous colloidal solutions

“…1,2 By using bifunctional (such as thioglycolic [3][4][5][6] or mercaptopropionic acids), tri-functional (cysteine or glutathione [7][8][9] ), or polyfunctional (e.g. polyethyleneimine 10 ) ligands, stable colloidal Ag-In-S (AIS) and Cu-In-S (CIS) QDs can be produced in aqueous solutions under mild conditions by means of "green" colloidal chemistry with a variety of compositions and sizes, showing high potential for applications in light-emitting 4,7 and lightharvesting 5,9 applications. The multifunctional ligands saturate under-coordinated metal atoms on the QD surface via coordination bonds and, at the same time, form an electrostatic barrier precluding inter-QD interactions and their agglomeration.…”