The increasing use of semiconductors in everyday life has triggered the search for new materials, as well as obtaining more efficient synthesis methods with a wide range of technological applications, thus becoming a field of research in the border of basic and applied knowledge.
In particular, one of the most interesting families of semiconductors is the family of mixed tungsten oxides, which are a class of multifunctional materials with innovative physical and chemical properties that cover a wide spectrum of applications. At the same time, in recent years, investment in research to obtain efficient bactericidal agents has increased.
Researchers of the departments of Physics, Inorganic and Organic Chemistry and Physical and Analytical Chemistry of the Universitat Jaume I, the Functional Materials Development Centre of Brazil and the Technical University of Liberec (Czech Republic) have developed a new technique to obtain complex nanocomposites formed by metallic silver nanoparticles doped in crystal of silver tungstate semiconductor that improve 32 times their bactericidal performance.
The research team has published the article “Towards the scale-up of the formation of nanoparticles on α-Ag2WO4 with bactericidal properties by femtosecond laser irradiation” in the journal Scientific Reports (Nature), in which they explain a new synthesis process based on the irradiation of light on the surface of the semiconductor in an extremely short time, specifically in femtoseconds (10 -15 seconds).
This technique allows the segregation of metallic silver from the semiconductor forming silver nanoparticles on the surface. The semiconductor attracts the bacterial agents and the nanoparticles of Ag neutralize them. “This silver tungstate — explain the researchers — is highly bactericidal when applied to a colony of bacteria, about 32 times more effective than the materials used so far”, they emphasize.
In this way, the interaction between the semiconductor and pulsed laser radiation in femtoseconds opens up possibilities in obtaining high performance and easy-to-manufacture bactericidal compounds, since ultra-short laser irradiation can be easily integrated into the production process. Research has also revealed that laser-driven synthesis offers a rich variety of chemical species, such as black species or red cloud species.
The finding extends fundamental knowledge about the effects of the interaction between laser and matter, while also being an inspiration for the efficient synthesis of nanocomposites. The research team works on the ability to adjust the effect induced by the laser by varying its power and the time of irradiation that could open a new field in the synthesis of novel materials with a wide range of photocatalytic or photoswitch applications in fields such as medicine or technology.
This work is the result of an international cooperation project within the framework of the Functional Materials Development Centre (CDMF) of the Federal University of São Carlos (UFSCar) of Brazil, researchers from the departments of Physics, Inorganic and Organic Chemistry, and Physical and Analytical Chemistry of the Universitat Jaume I and the Czech university of Liberec.
Towards the scale-up of the formation of nanoparticles on α-Ag2WO4 with bactericidal properties by femtosecond laser irradiation. Scientific Reports, volume 8 (2018) http://www.nature.com/articles/s41598-018-19270-9
Autores: Elson Longo, Edson R.Leite, Marcelo Assis y Regiane Oliveira (UFSCar); Carlos E. Vergani y Camila C. Foggi (FOAR-Unesp-Araraquara); Juan Andrés, Eloisa Cordoncillo, Héctor Beltrán y Gladys Mínguez (Universidad Jaume I -UJI); y Rafael Torres-Mendieta (University of Liberec Studentská – Liberec Czech Republic).