Multifunctional Ag nanoparticle decorated Si nanowires for sensing, photocatalysis and light emission applications

Ramesh Ghosh; Joydip Ghosh; Ruma Das; Larionette P L Mawlong; Kamal Kumar Paul; P K Giri

doi:10.1016/j.jcis.2018.07.123

Multifunctional Ag nanoparticle decorated Si nanowires for sensing, photocatalysis and light emission applications

J Colloid Interface Sci. 2018 Dec 15:532:464-473. doi: 10.1016/j.jcis.2018.07.123. Epub 2018 Jul 29.

Authors

Ramesh Ghosh¹, Joydip Ghosh², Ruma Das², Larionette P L Mawlong³, Kamal Kumar Paul², P K Giri⁴

Affiliations

¹ Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India; Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India; Department of Physics and Astronomy, Seoul National University, Seoul 151747, Republic of Korea.
² Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India.
³ Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India.
⁴ Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India; Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati 781039, India. Electronic address: giri@iitg.ernet.in.

PMID: 30099309
DOI: 10.1016/j.jcis.2018.07.123

Abstract

We report on the fabrication of Ag nanoparticle (NP) decorated mesoporous Si nanowire (NW) heterostructure (HS) by a simple and low cost chemical process. The as-grown Si NWs are mesoporous in nature and the Ag NP decorated Si NWs (Ag@Si NWs) exhibit broadband light emission, ultralow reflectance, efficient photocatalytic degradation of organic dyes and excellent sensitivity for the detection of organic molecules over a wide range of concentration. The broadband white light photoluminescence emission from the bare Si NWs is explained on the basis of quantum confinement effect in Si NCs/NWs and the nonbridging oxygen hole center defects in the SiSiO_x interface. High work function of the noble metal NPs facilitates the effective separation of the photoinduced electron-hole pairs in Si NWs, which enables the Ag@Si NWs to exhibit high photocatalytic efficiency for the degradation of organic dye. The Ag@Si NWs exhibited high potential and sensitivity for the selective and quantitative detection of different organic molecules at extremely low concentration down to 10^-12 M by surface-enhanced Raman scattering and 10^-11 M by fluorescence-based detection. These versatile properties of the Ag@Si NWs open up opportunities for a variety of energy and environmental applications, such as white light emission, solar cell, artificial photosynthesis, disposal of organic pollutant and bio-chemical sensors etc.

Keywords: Ag nanoparticles; Chemical sensing; Photocatalysis; Photoluminescence; SERS; Si nanowires.