Can surface capping ligands probe cation exchange in inorganic nanoparticles?

Abstract

Cation exchange by post-synthetic modification of inorganic nanoparticles (NPs) are commonly monitored by probing alterations of NP’s core, and not much is known on surface capping ligand’s ability to probe...

Remarkable difference in pre-cation exchange reactions of inorganic nanoparticles in cases with eventual complete exchange

“…41 In one of our recent works, by systematically monitoring the NPs in the presence and absence of cation exchange, we have demonstrated that the infrared absorption of the surface capping ligand 1-thioglycerol (1-TG) can track the cation exchange reaction in both the ZnS and Zn(Tb)S NPs. 37 This study further emphasizes the fact that the involvement of surface atoms in initiating cation exchange in inorganic NPs propagates into the surface capping ligand, hence including them in the reaction zone as well. An involvement of the entire structure of 1-TG covering both the terminal groups and backbone bonds is involved, as monitored by the tuning of the IR absorption of OH stretching, OH in-plane bending, CH 2 in-plane bending, C–C stretching/C–O stretching, OH out-of-plane bending, and C–S stretching vibrations.…”

“…Their signatures were not evident in the FTIR spectra. 25,37 This post-synthetic protocol of Zn(Tb)S NPs with [Zn(Tb)S] : [Pb 2+ ] ratio of 1 : 10 −4 , 1 : 10 −2 , and 1 : 1 resulted in cubic Zn(Tb)(Pb)S, Zn(Tb)(Pb)S, and Pb(Tb)S NPs with 3.0 ± 0.5, 3.2 ± 0.4, and 3.9 ± 0.6 nm (average ± standard deviation) diameter, respectively. 24…”

“…Their signatures were not evident in the FTIR spectra. 25,37 This post-synthetic protocol of Zn(Tb)S NPs with [Zn(Tb)S] : [Pb 2+ ] ratio of 1 : 10 À4 , 1 : 10 À2 , and 1 : 1 resulted in cubic Zn(Tb)(Pb)S, Zn(Tb)(Pb)S, and Pb(Tb)S NPs with 3.0 AE 0.5, 3.2 AE 0.4, and 3.9 AE 0.6 nm (average AE standard deviation) diameter, respectively. 24 X-Ray diffraction X-Ray diffraction (XRD) was performed using a PANalytical X'pert PRO diffractometer operated at a generator voltage of 45 kV and a current of 40 mA with Cu Ka radiation (l = 0.154 nm).…”

“…29,[32][33][34][35][36] A method to predict the favorable combination of the incoming-outgoing cation pair in a cation exchange reaction in inorganic NPs based on thermodynamic grounds is discussed by Alivisatos and coworkers. 17 This exercise computes a negative free energy of reaction for Zn 2+ -Hg 2+ and Zn 2+ -Pb 2+ pairs with the DG 0 reaction being À160.8 and À20.2 kJ mol À1 , respectively, 37 thus predicting the possibility of exchanging Zn 2+ from the ZnS-based NPs by the post-synthetic addition of either Hg 2+ or Pb 2+ . Indeed, experimentally, such an exchange is discussed independently by various research groups.…”

Maximizing Terbium–Europium Electronic Interaction: Insight from Variation of Excitation Energy

“…EDS is used to determine the elemental composition of nanomaterials. ,,,,− The elemental composition of Ca­(Ln)­F 2 [Ln = Tb, Eu], as determined from the EDS measurements, reveals atomic percentages of Ca:Ln (Tb/Eu):F = 32.0 ± 2.0:3.6 ± 0.3:64.4 ± 2.2 and 37.8 ± 2.1:3.6 ± 0.2:58.6 ± 2.2, respectively. Co-doped Ca­(TbEu)­F 2 and Ca­(TbGd)­F 2 particles show elemental compositions of Ca:Tb:Eu/Gd:F = 29.4 ± 2.1:3.1 ± 0.2:3.6 ± 0.2:63.9 ± 2.3 and 28.5 ± 0.3:3.0 ± 0.2:2.8 ± 0.1:65.7 ± 0.3, respectively.…”