Silica-coating-assisted nitridation of TiO2 nanoparticles and their photothermal property

• Published in: Nano research Vol. 14; no. 9; pp. 3228 - 3233
• Main Authors: Wei, Qilin, Kuhn, Danielle L., Zander, Zachary, DeLacy, Brendan G., Dai, Hai-Lung, Sun, Yugang
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01-09-2021; Springer Nature B.V
• Subjects: Absorption; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Broadband; Carrier density; Charge density; Chemistry and Materials Science; Condensed Matter Physics; Core-shell particles; Current carriers; Electromagnetic absorption; Free electrons; High temperature; Materials Science; Nanoparticles; Nanotechnology; Near infrared radiation; Photothermal conversion; Refractory compounds; Research Article; Shells; Silica; Silicon dioxide; Titanium; Titanium dioxide; Titanium nitride; titanium-oxide-nitride nanoparticles; structural transformation; nitridation reaction; photothermal effect; plasmonic absorption; mesoporous silica coating
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-021-3427-7

Nanoparticles of refractory compounds represent a class of stable materials showing a great promise to support localized surface plasmon resonances (LSPRs) in both visible and near infrared (NIR) spectral regions. It is still challenging to rationally tune the LSPR band because of the difficulty to control the density of charge carriers in individual refractory nanoparticles and maintain the dispersity of nanoparticles in the processes of synthesis and applications. In this work, controlled chemical transformation of titanium dioxide (TiO
2
) nanoparticles encapsulated with mesoporous silica (SiO
2
) shells to titanium nitride (TiN) via nitridation reaction at elevated temperatures is developed to tune the density of free electrons in the resulting titanium-oxide-nitride (TiO
x
N
y
) nanoparticles. Such tunability enables a flexibility to support LSPR-based optical absorption in the synthesized TiO
x
N
y
@SiO
2
core-shell nanoparticles across both the visible and NIR regions. The silica shells play a crucial role in preventing the sintering of TiO
x
N
y
nanoparticles in the nitridation reaction and maintaining the stability of TiO
x
N
y
nanoparticles in applications. The LSPR-based broadband absorption of light in the TiO
x
N
y
@SiO
2
nanoparticles exhibits strong photothermal effect with photo-to-thermal conversion efficiency as high as ~ 76%.