Group's thesis

Thesis defended in the group since 2014


Wire on suspended structure
PhD Pablo Ferrando Villalba after thesis

Thermal characterization of Si-based nanomaterials

Pablo Ferrando Villalba

Thermoelectricity is a promising technology for scavenging energy from environmental temperature differences. The development of materials that transform heat into electricity in a more efficient way making use of this principle is necessary for opening new application niches. Nanostructuring a material has been demonstrated to increase the thermoelectric figure of merit of crystalline materials via a thermal conductivity reduction driven by enhanced phonon scattering. This thesis is committed to give a better insight into the processes that affect thermal transport in potential Si-based nanomaterials for thermoelectric generation.

Link to the thesis manuscript

Ultrastable glasses of celecoxib
PhD Cristian Rodríguez Tinoco after  thesis


Calorimetric study of vapour deposited glasses: beyond conventional stability and temperature limits

Cristian Rodríguez Tinoco

Vapour deposition has emerged as a very powerful tool to produce glasses of unprecedented stability. By tuning the deposition conditions, one can tailor the properties of the deposited glass. In particular, at substrate temperatures around 0.85Tg, the maximum stability is reached. On the other hand, fast-scanning nanocalorimetry has proven to be an extremely useful technique to evaluate different characteristics of the mechanisms behind the glass transition at temperatures much above the typically explored low temperature range. In this thesis, we present a detailed study of different aspects of the glass transition on vapour deposited organic glasses of Indomethacin and Celecoxib, by combining a variety of calorimetric techniques, from conventional to fast-scanning calorimetry, including high pressure-calorimetry. Stable glasses produced from the vapour phase exhibit a different transformation mechanism with respect to glasses obtained by cooling the liquid.

Link to the thesis manuscript


Nanocalorimeter sketch
PhD Manel Molina Ruix after thesis

Nanocalorimetric studies of size effects in magnetic oxides and formation kinetics in silicides

Manel Molina Ruiz

The advances in Nanoscience and Nanotechnology have been paved by the continuous development of new techniques adapted to small samples. In that framework, calorimetry is a technique suitable to measure thermodynamic properties and energetic processes, such as phase transitions, through the heat absorbed or released by the system. Taking profit of advances in microfabrication techniques a new family of nanocalorimeters, based on ultra-light calorimetric cells and built up onto thin film dielectric membranes, has emerged demonstrating enhanced sensitivities compared with traditional calorimeters, reaching levels better than 1 nJ K-1 mm-2. This technique has permitted to several research groups to explore new physical phenomena inaccessible before. The present research work deals with the development and optimization of this technique: the nanocalorimetry. We enlarge the dynamic ranges of applicability from ultrafast heating rates to quasi-static ones, and we demonstrate its utility in the study of different phase transitions at nanoscale.

Link to the thesis manuscript

Campus d'excel·lència internacional U A B