Using ultrashort laser pulses to “clone” gold nanoparticles
Researchers and students of the Universidad Politécnica de Madrid (UPM) / Institute of Nuclear Fusion, located in the Higher Technical School of Industrial Engineers, participate in a study that reports the use of ultra-short laser pulses to mold “nano-rods” of gold in aqueous solution. The work shows that the solution with the modified particles has an optical quality never seen before. The study was published on November 3, 2017 in the journal Science.
The applications of metallic nanoparticles are based on their ability to absorb and reflect light of certain colors very efficiently. These effects, called plasmonic, generate completely new optical properties, which cannot be obtained with structures of larger dimensions. These properties can be exploited for an incredibly large number of useful applications, which in many cases were not possible until now.
In medicine, for example, the light reflected by these particles can be used to diagnose diseases and the absorption of light can also be used to heat a very small volume and, for example, to treat tumors in a localized way and minimizing the usual side effects of Current treatments These plasmonic particles have also found applications in areas such as information technologies, energy production or environmental pollution control, among others.
» READ MORE
In this work the gold nanoparticles were prepared by chemical methods in solution, but the really revolutionary concept is the application of ultra-short laser pulses for modulating the geometry of the particles and perfecting their optical properties. Likewise, to understand the chemical and physical nature of the molding process, standard characterization techniques (electron spectroscopy and microscopy) have been used, as well as new theoretical models and advanced computer simulation techniques. The vast majority of these simulations were carried out at the UPM, taking advantage of the infrastructure provided by CESVIMA.
According to Ovidio Peña Rodríguez, a researcher at UPM, “the manufacture of optically identical particles and the explanation of the underlying processes, represents a change in mentality that can open new avenues to the development of nanomaterials with improved properties and applications.” “The study of the modification of materials under irradiation is a very important issue for our Institute,” adds José Manuel Perlado, Director of the UPM Nuclear Fusion Institute.
However, the research goes beyond using lasers as chisels in the hands of a sculptor to obtain the record of optical quality, where billions of gold nanoparticles behave as if they were one. According to Antonio Rivera, a researcher at the Polytechnic University of Madrid, “the study also provides the physical and chemical keys necessary to understand and control the process that gives rise to perfect nanomaterials from the point of view of their optical properties.”
In addition to the researcher Ovidio Peña Rodríguez, and UPM professor Antonio Rivera de Mena, researchers from the Complutense University of Madrid have also participated (Andrés Guerrero Martínez, Luis González Macdowell, Mauricio Alcolea Palafox, Gloria Tardajos, Luis Bañares and Jesús González Izquierdo ) and the CIC biomaGUNE in San Sebastián (Luis Liz Marzán). PhD students Pablo Díaz Núñez and Alejandro Prada (UPM), Guillermo González Rubio (UCM and CIC biomaGUNE) and Pablo Llombart (UCM) made important contributions. In the development of this research, it has been essential to use the infrastructures of the Supercomputing and Visualization Center of Madrid (CESVIMA-UPM), the CIC biomaGUNE and the Center for Ultrafast Lasers (UCM).
» READ LESS