Single-stage formation of Ag nanoparticles on α-Ag2WO4 network by femtosecond laser irradiation

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F46747885%3A24620%2F18%3A00005485" target="_blank" >RIV/46747885:24620/18:00005485 - isvavai.cz</a>

Result on the web

<a href="http://angel-conference.org/" target="_blank" >http://angel-conference.org/</a>

DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Single-stage formation of Ag nanoparticles on α-Ag2WO4 network by femtosecond laser irradiation

Original language description

The ternary tungsten oxides family, generally denoted as MWO4, have emerged as an important multifunctional semiconductor family that have showed a powerful potential in several application areas such as hydrogen generation, multiferroic applications, catalysis, among others. In particular silver tungstate (α-Ag2WO4), which is considered part of the semiconductor family, has recently emerged as a multifunctional alternative over conventional wide band-gap semiconductors, owing to its potential in applications such as photocalalysis, photoswitching, among others. Recent studies have also demonstrated that crystals of α-Ag2WO4 showed a metal nanoparticle (MNPs) growth attached to the semiconductor framework while analyzing the semiconductor by Transmission Electron Microscope (TEM), the phenomenon may lead to outstanding applications due to Ag segregation, such as ozone sensing and bacteriocidicity. Up to now, the MNPs growth has been limited to TEM processing, thus hampering its exploitation as a competitive bactericidal product among others. In this communication, a different perspective is studied to scale-up the segregation of Ag nanoparticles (NPs) in the framework of the semiconductor. Femtosecond laser radiation (Ti:sapphire laser, 30 fs pulses, 1kHz, 800nm central wavelenght) is used to irradiate large areas of α-Ag2WO4 in air, in order to promote an instantaneous nucleation and growth of Ag NPs. Afterwards, the material is tested as bactericidal agent against Methicillin-Resistant Staphylococcus Aureus ATCC 33591. Two different protocols are studied to consider the influence of the energy in the segregated species; a low energy regime leading to the synthesis of Ag nanoparticles anchored onto the surface of the semiconductor, and a high energy regime leading to high material removal where the formation of Ag nanoparticles is accompanied by the synthesis of a new type of nanoalloy AgxWyOz, and the biggest bactericidal activity is achieved. All the resultant species are examined and identified using TEM, energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) in powder, scanning microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results are compared with the segregation of Ag nanoparticles on α-Ag2WO4 using the accelerated electron beam from an electronic microscope under a high vacuum. The samples irradiated by femtosecond radiation at a high fluence regime show the best antibacterial performance found in the literature up to now, a 32-fold improvement over non-irradiated α-Ag2WO4. We believe that the results found in current communication constitute an improvement over conventional multifunctional semiconductor synthesis approaches, which may inspire future developments.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

21001 - Nano-materials (production and properties)

Project

<a href="/en/project/LM2015073" target="_blank" >LM2015073: Nanomaterials and Nanotechnologies for Environment Protection and Sustainable Future</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů