Femtosecond laser synthesis of nonstoichiometric molybdenum oxide nanoparticles
Anton S. Chernikov, Dmitriy A. Kochuev, Maria A. Dzus, Ruslan V. Chkalov, Elena I. Shingareva, Kirill S. Khorkov; Vladimir State University, Vladimir, Russia
Abstract
Synthesis of nanoparticles of nonstoichiometric molybdenum oxide (MoO3-x) was carried out by femtosecond laser fragmentation in a liquid medium. Ethanol (95%) was used as the liquid medium, and suspensions prepared from commercial MoS2 powder were used as the irradiation object. Laser exposure to a suspension in ethanol for 10 minutes leads to the transformation of the initial powder into a near-spherical LF, the average size of the LF is 38 nm, while a number of submicron particles of random shape can be observed. An increase in the duration of laser fragmentation (60 minutes) leads to a decrease in the size of nanoparticles, so the average size of nanoparticles is about 26 nm. In addition to studying the optical properties of synthesized nanoparticles in the initial liquid medium (95% ethanol), the possibility of transferring particles to another liquid medium (deionized water) and their further characterization and functionalization was of interest. Due to the small size of the nanoparticles, the use of the centrifugation technique for sedimentation of nanoparticles and their transfer to the required medium was not effective with a relative centrifugal force of 15,000 RCF. The final step was to use BSA as a stabilizer for synthesized NPS, as well as to evaluate the effect of BSA concentration on the optical and photothermal properties of colloidal systems. The prepared solution of WoO3-x NPS in deionized water was poured into test tubes (required volume of 1 ml), in which the required amount of BSA (0, 1.25, 2.5, 5 mg) was added in advance. The tubes were placed in an ultrasound bath for 30 minutes at a temperature of 37 °C. Before starting the study of optical and photothermal properties, the solutions were cooled to room temperature, depending on the amount of added BSA, the color of the solution changed from saturated blue to light blue. The measurements were carried out in quartz cuvettes with an optical path length of 10 mm and a filling volume of 1 ml. The duration of the irradiation of colloidal solutions was 10 minutes, followed by cooling to 10 minutes, and the radiation power was 0.7 W.
This study was funded by the Russian Science Foundation (Grant No. 24-12-20015).
Speaker
Kirill Khorkov
Vladimir State University
Russia
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