Luminescence Study of Silver Nanoparticles Obtained by Annealed Ionic Exchange Silicate Glasses

Abstract

The photoluminescence of silver nanoparticles glasses obtained by ionic exchange and annealing is investigated for various ionic exchange times. These glasses are prepared by immersion of silicate glass samples in a molten salt bath of molar concentration 10% AgNO 3 in NaNO 3 at T=320°C. Scanning electron microscopy measurement in electron diffraction scattering (EDS) configuration confirms the silver presence in the various glasses, and the UV/visible absorption gives the evolution of the spectra after ionic exchange and plasmon resonance apparition after annealing. After annealing at 450°C, both diagnostics inform us about the particles' formation and the silver rediffusion. Silver nanoparticle growth after annealing prior leads to photoluminescence exaltation and quenching for the longest exchange samples. Subsequently, we propose potential mechanisms of the nanoparticle formation with an initial depolymerization of the silicate network during the ionic exchange and repolymerization during annealing.

Thermo-Optical Effects in Plasmonic Metal Nanostructures

“…However, PL from metal NPs (NPs) has not been studied thoroughly, partly due to the low probability of corresponding radiative transitions in the metals noted above. The PL of noble metal NPs has been reported for Ag [62][63][64][65], Au [66,67], and Cu [68,69]. Each of these studies revealed a maximum of the PL band close to the interband absorption edge, so the PL was attributed to the interband radiative transitions.…”

Surface plasmon enhanced photoluminescence from copper nanoparticles: Influence of temperature

“…Second term c eÀe in Eq. (5), the rate of electron-electron scattering is expressed as the sum of the temperature dependent and the frequency dependent terms 52 c eÀe ðx; TÞ ¼ c T e ðTÞ þ c f e ðxÞ; (8) where c T e ðTÞ ( c eÀph and, correspondingly, is neglected in our calculations, while frequency dependent term is expressed as 53…”

“…The PL from metal nanoparticles (NPs) has not been studied much as well, partly because of the very low probability of corresponding radiative transitions in the metals noted above. The PL of noble metal NPs has been reported for silver, [6][7][8][9] gold, 10,11 and copper. 12,13 All these studies revealed the maximum of the PL band close to the interband absorption edge and, thus, the PL was attributed to the interband radiative transitions.…”

Investigation of the role of silver species on spectroscopic features of Sm3+-activated sodium–aluminosilicate glasses via Ag+-Na+ ion exchange

“…Optical properties of these different ionic silver species in silver ion-exchanged glasses have been widely studied because they lead to a novel broad emission, covering 350 nm to 610 nm. [17][18][19][20][21][22][23] In fact, the outermost electron 4d 10 -4d 9 5s 1 transitions of silver ions give rise to typical luminescence features whose shape and position depend on the local ion environment and on the formation of aggregates or dimers in the glass matrix. 19 In particular, four main features have been identified: a UV band around 350 nm, which is attributed to Ag þ spin-allowed transitions from the 1 D 2 state to the 1 S 0 ground state under about 250 nm excitation; 23 a violet band at about 420 nm, which is attributed to Ag þ spin-forbidden transitions of the type 3 D 1À3 -1 S 0 ; 19,21 a deep-blue band at about 450 nm attributed to (Ag 2 ) þ ; 11,18,20,24 and a green band at about 525 nm attributed to Ag þ -Ag þ pairs.…”

“…19 In particular, four main features have been identified: a UV band around 350 nm, which is attributed to Ag þ spin-allowed transitions from the 1 D 2 state to the 1 S 0 ground state under about 250 nm excitation; 23 a violet band at about 420 nm, which is attributed to Ag þ spin-forbidden transitions of the type 3 D 1À3 -1 S 0 ; 19,21 a deep-blue band at about 450 nm attributed to (Ag 2 ) þ ; 11,18,20,24 and a green band at about 525 nm attributed to Ag þ -Ag þ pairs. 11,17,19,22,24 The excitation source that could be used to generate blue and green emission is about 350 nm UV light. In the early literature, 23 the bluer/green band emission is assigned to spin-forbidden transitions from the 3 D manifold to the ground state.…”