Rare-Earth Sulfide Nanocrystals from Wet Colloidal Synthesis: Tunable Compositions, Size-Dependent Light Absorption, and Sensitized Rare-Earth Luminescence

Abstract

We report the synthesis of colloidal EuS, La 2 S 3 , and LaS 2 nanocrystals between 150 and 255 °C using rare-earth iodides in oleylamine. The sulfur source dictates phase selection between La 2 S 3 and LaS 2 , which are stabilized for the first time as colloidal nanocrystals. The indirect bandgap absorption of LaS 2 shifts from 635 nm for nanoellipsoids to 365 nm for square-based nanoplates. Er 3+ photoluminescence in La 2 S 3 :Er 3+ (10%) is sensitized by the semiconducting host in the 390−450 nm range. The synthetic route yields tunable compositions of rare-earth sulfide nanocrystals. Interaction of light with these novel semiconducting nanostructures hosting rare-earth emitters should be attractive for applications that require broadband sensitization of RE emitters.

New Hyperbranched Polysiloxanes Made by Thiol‐yne Click Reaction: Lanthanide Complexation and Applications in Bioimaging

“…1 H NMR (400 MHz, CDCl 3 ) 𝛿 = 0.049-0.153 (-SiCH 3 ), 𝛿 = 0.80-0.92 (-CH 2 CH 3 ), 𝛿 = 1.42-1.52 (-CH 2 CH 3 ), 𝛿 = 1.57-1.66 (-SH), 𝛿 = 2.57-2.67 (-C═O-CH 2 ), 𝛿 = 2.69-2.83 (S-CH 2 -), 𝛿 = 3.96-4.1 (O-CH 2 -). 13 C NMR (100 MHz, CDCl 3 ): 𝛿 171.06, 67.72, 63.54, 40.85, 38.15, 36.42, 34.52, 32.03, 28.68, 27.68, 25.51, 22.75, 19.42, 7.01, 1.51. Synthetic method of P2-Ln 3+ was shown in S1 (Supporting Information).…”

“…The 1 H-NMR spectra (Figure 3) and 13 C-NMR spectra (S2, Supporting Information) of P1 and P2 had been obtained by adding overdose TMSA. The capped sulfhydry -SH of TTMP corresponded to the peak at 1.56 ppm (3a).…”

“…[11,12] The extraordinary 4f sublayer electronic structure enables lanthanides to exhibit exceptional fluorescence properties in the fields of light, electricity, and magnetism. [13][14][15][16][17] Weissman proposed the concept of "antenna effect" in 1942 to solve problem that lanthanides are forbidden for f-f transitions. Using organic ligands with larger extinction coefficients to coordinate with lanthanide ions and then energy transfer from the ligand to the excited lanthanide ions to increase the fluorescent intensity of lanthanide ions.…”

Blue-LED-excitable NIR-II luminescent lanthanide-doped SrS nanoprobes for ratiometric thermal sensing

“…Until recently, the new class of NIR-II luminescent nanoprobes based on Ln 3+ -doped sulphides (namely, CaS and NaGdS 2 ) have been proposed by our group [46,47]. In comparison with fluorides, sulphide NCs exert a stronger CF and a higher covalency on Ln 3+ emitters [48][49][50]. As a result, the absorption and emission of Ce 3+ and Eu 2+ ions with allowed 4f→5d transitions locate at lower energies in sulphides (in the visible (vis) region) than in fluorides and oxides (in the ultraviolet (UV) region), which promises Ce 3+ and Eu 2+ activated sulphides as efficient phosphors in white light-emitting diodes (LEDs) [51][52][53].…”

Anisotropic growth of ZnO nanoparticles driven by the structure of amine surfactants: the role of surface dynamics in nanocrystal growth

“…39 In this context, the use of amines with long fatty chains as surfactants, like the archetypal oleylamine, 40 is very popular to achieve good control of the morphology of NCs. The high boiling point of oleylamine, above 360 °C, allowed using it in thermolytic reduction processes whether in a "heat up" approach, [41][42][43][44][45][46][47][48][49] or through the so-called "hot-injection" [48][49][50][51] technique. Hexadecylamine, dodecylamine and octylamine are also extensively used under milder conditions for the formation of metallic, II-VI or III-V semiconductor NCs.…”