Structure and Properties of Amorphous Silica and Its Related Materials: Recent Developments and Future Directions

Abstract

Amorphous silica and related silicabased materials have been widely developed in optoelectronics and optical telecommunications technology. Despite comprehensive research for over the decades, the subject of amorphous silica continues to excite the interest of researchers in the field of chemistry, physics, and geology. This paper reviews some of the recent experimental and theoretical developments in the field, including mediumrange ord er, structural changes under pressures, vibrational and thermodynamic anomalies, and photoluminescence properties.

Properties of Amorphous Silica Synthesized from Copper-Smelting Slags

“…[1][2][3][4][5]. Composite materials based on highly dispersed amorphous silica are also widely used in optoelectronics and optotelecommunication technologies [6,7]. Secondly, the study of the amorphous silica structure makes it possible to reveal its new properties, which depend heavily on the method and conditions of synthesis, as well as on the characteristics of the raw materials [7,8].…”

Favoured local structures in liquids and solids: a 3D lattice model

“…The role of local structure in liquids remains a more challenging question. The structure of molten salts has generated an extensive literature [12] as has the structures in liquids characterized by local tetrahedral order such as silica [13]. Even in cases when the local structures are complex and multiple, there exists a strong conviction that they represent an essential key to understanding the properties of the low temperature phases.…”

“…The structure of molten salts has generated an extensive literature 11 as has the structures in liquids characterized by local tetrahedral order such as silica. 12 Even in cases when the local structures are complex and multiple, there exists a strong conviction that they represent an essential key to understanding the properties of the low temperature phases. A considerable body of work addresses the favoured local structures in binary and ternary atomic alloys.…”

Visible luminescence peculiar to sintered silica nanoparticles: Spectral and decay properties

“…Its reduction to nanoscale introduces structural differences due to a more flexible Si-O-Si network characterized by an increased population of three-and fourmembered rings [3]. The high specific surface ( 10 m /g 2 2 ∼ ) favors the formation of a wide variety of surface defects which confer both a high reactivity with atomic and molecular species of the environment [4] and functional properties such as the high emissivity [5][6][7][8][9][10]. Indeed, in ambient atmosphere silica nanoparticles are decorated by silanol (Si-OH) groups and physisorbed water molecules [3]; moreover, under UV excitation, they exhibit a bright blue emission which has been associated with surface defects [9,11,12].…”

“…This process can be activated by thermal treatments at temperatures ( 900 C >°) far below the melting point ( 2000 C ∼°) [16] or by compression under high pressures ( 6 GPa > ) at room temperature [13]. Infrared absorption and Raman scattering investigations have evidenced that in the medium range order ( 0.5 to 5 nm ∼ ∼ ) the structural properties of sintered material are very similar to bulk silica [6,16,17]. In contrast, both atomic force microscopy (AFM) [17] and field emission scanning electron microscopy (FESEM) [16] images reveal that sintered samples retain a particulate morphology in the long range order ( 10 nm > ∼ ) with grains whose diameter increases with the duration of the thermal treatment.…”