In Situ Growth of Low-Dimensional Silver Nanoclusters with Their Tunable Plasmonic and Thermodynamic Behavior

Abstract

Optical properties of noble metal nanostructures associated with localized surface plasmon resonance (SPR) are technically important for optical switches and plasmonic devices. In this work, silver nanoclusters are embedded inside the soda-lime glass matrix, followed by a thermal annealing process in an open air atmosphere for 1 h. The effects of thermal annealing on the plasmonic behavior of Ag nanoclusters embedded in the glass matrix are studied with UV–vis spectroscopy and photoluminescence. In the SPR spectra, a 14 nm blue shift is observed in the visible range under the influence of thermal annealing at a higher temperature. The thermal effects on Ag particle size and SPR have been illustrated for plasmonic properties. The structural and elemental investigation of as-grown Ag nanoclusters is confirmed by X-ray diffraction, high-resolution transmission electron microscope, and X-ray photoelectron spectroscopy. The structural, plasmonic, and thermodynamic properties associated with the growth mechanism of Ag nanoclusters have been explained under the thermal process. Enthalpy (Δ H ), entropy (Δ S ), and Gibbs energy (Δ G ) for Ag nanoclusters growth and nucleation are significantly calculated and interpreted at different temperatures. An empirical relation among the Δ H , Δ S , and Δ G is developed vis-a-vis activation energy (97.70 J/mol), which is calculated by the Arrhenius linear equation.

Thermodynamically induced in Situ and Tunable Cu Plasmonic Behaviour

“…15). The ∆H values revealed the reduction process of reduced Cu atoms through a redox while ∆S helps to understand the Cu NPs reorientation mechanism which was reported in our previous work 44 . These two thermodynamic parameters collectively have inferred thermal growth and accumulation behaviour which utilize almost all the energy in a process to balance a minimum energy.…”

“…These two thermodynamic parameters collectively have inferred thermal growth and accumulation behaviour which utilize almost all the energy in a process to balance a minimum energy. Spontaneity of any chemical reaction could be represented by Δ G values 45 and thus, we have explained a dependence of Δ G in favour of Cu NPs formation within dielectric matrix. During the growth and nucleation of Cu atoms, a decrease in Δ G value is observed with an increase in annealing temperatures.…”

“…Further, the cleaned pristine samples were annealed from 550 °C to 650 °C for 1 h. At lower temperature, the few Cu ions were formed by Cu-O bond breaking and the ions required energy for moving towards a more relaxed surface. Thus, on increasing temperature larger Cu segregation and diffusion were occurred on glassy surfaces which was understood by the differences in the sizes of Cu + and Na + 44,46,47 .…”

Study of Tunable Plasmonic, Photoluminscence, and Nonlinear Optical Behavior of Ag Nanoclusters Embedded in a Glass Matrix for Multifunctional Applications

“…It must be pointed out that the calculated clusters sizes obtained from FEGTEM are smaller than the crystallite size as calculated from using the Scherrer formula and the XRD patterns. Inwati et al have recently reported a similar trend of crystalline size difference as estimated from XRD which was also not consistent with the size estimated from FEGTEM. This may be attributed to the effect of crystal breakage due to crushing of the silver embedded glass into the fine powder, which has been used for the FEGTEM measurements.…”

“…The transformation of the Ag + ions to Ag 0 neutral atoms under thermal treatments, are explained below where the glass impurities provides the necessary electrons to reduce the Ag + → Ag 0 (Scheme ) …”