PCAM Seminar 11 May
We look forward to two presentations from UAM within this hour:
Optical Trapping of Rare-earth doped Microparticles: Applications of a rotating particle, nanoBIG group
Elisa Ortiz Rivero, Departamento de Física de Materiales, Universidad Autónoma de Madrid,
Supervisor: Patricia Haro González.
Nanomaterials for bioimaging group (nanoBIG), Departamento de Física de Materiales, Universidad Autónoma de Madrid
Precise and non-invasive control over single particles is key for a range of physical and bio-medical applications, such as microfluidics and biophysics. The three-dimensional optical trapping of a microparticle provides information of small-sized systems, from photonic devices to cells in a contactless way. In particular, the manipulation of single rare-earth-doped luminescent particles is of great interest due to their biocompatibility and the sensitivity of their luminescent properties to environmental conditions which stand out among other dielectric luminescent particles. [1] The induced rotation of an optically trapped microparticle is highly affected by the medium properties, such as temperature, viscosity or elasticity. [2] By selecting the trapping laser and an appropriate rare earth ions doping, a ß-NaYF4:RE3+ microparticle can additionally cool or heat the medium, simultaneously controlling and monitoring the temperature of its surrounding liquid. [3] The dynamics of the spinning microparticle are also affected by its volume or any change in its surface. This feature allows the development of a Protein G-coated NaYF4: Yb3+, Er3+ microparticle as a biosensor capable of detecting single cells and bacteria. Contrary to current biosensors, this novel method only requires a small among of sample and a few seconds to detect. [4]
In conclusion, the analysis of the rotation dynamics of an optically trapped microparticle is a novel and powerful tool that will allow not only the controlled and remote manipulation of the sensor, but also an improved characterization of the medium and fast recording of its content.
[1] E. Ortiz-Rivero et al., Front. Chem., 8, 593398 (2020)
[2] P. Rodríguez-Sevilla et al., Adv. Opt. Mater., 6 (12), 1800161 (2018)
[3] E. Ortiz-Rivero et al., Small, 2103122 (2021)
[4] E. Ortiz-Rivero, et al., Small, 15, 1904154 (2019)
The physics behind hydrogen production from water
Nuria Jiménez Arévalo; MIRE group, Departamento de Física de Materiales, Universidad Autónoma de Madrid
Supervisors: Fabrice Leardini and Isabel Jiménez Ferrer
The current climate situaon is becoming increasingly alarming due to rising temperatures, mainly caused by the emission of greenhouse gases due to the use of fossil fuel-based energy sources [1]. To address this problem, an energy transion towards renewable energy sources, which have the disadvantage of being intermitent, has been proposed. In this situaon, hydrogen has become a promising strategy as an energy carrier, as it allows renewable energy to be stored and transported [2].
Clean hydrogen is the one obtained aer its producon from water using green energy sources. Two ways of water spling stand out: electrolysis, in which electrical energy is used, and photoelectrolysis, in which light and electricity are applied [3].
In this seminar, the physics behind this chemical reacon is introduced. The mechanisms of the water spling reacon and the electrode-electrolyte juncon are explained. In addion, the main criteria that materials must meet to be used as electrodes, the state of the art of the subject and the challenges that sll have to be overcome for the real implementaon of this technology will be presented.
This talk aims to provide the audience with the basic knowledge to understand and follow future seminars and research about hydrogen producon from water and approach PhD students and other atendees to the fascinang world of (photo)electrochemistry.
[1] C. F. Schleussner et al., ‘Differential climate impacts for policy-relevant limits to global warming: The case of 1.5 °C and 2 °C’, Earth System Dynamics, vol. 7, pp. 327–351, 2016, doi: 10.5194/esd-7-327-2016.
[2] Andreas Züttel, Andreas Borgschulte, and Louis Schlapbach, Hydrogen as a Future Energy Carrier. Wiley-VCH, vol.7, no.3, pp. 343-344, 2008. doi: 10.1002/9783527622894.
[3] Craig A. Grimes, Oomman K. Varghese, and Sudhir Ranjan, Light, Water, Hydrogen. The Solar Generation of Hydrogen by Water Photoelectrolysis, vol. 546. New York: Springer, 2008.