Research Highlights

Recent highlights of the group research work

– Advances in NMR spectroscopy and relaxometry of liquid crystal dendrimers

The characterization of of soft matter systems by NMR spectroscopy and conventional and fast field cycling NMR relaxometry, combined with x-ray diffraction and polarising optical microscopy, contributes to the understanding of the relation between the systems microscopic properties (including molecular structure, molecular organization and interaction with confining matrices) and their macroscopic physical behavior. Specific properties, relevant for applications, like diffusion constants and visco-elastic parameters are especially taken into account. The application of these NMR techniques to the field of Liquid Crystal Dendrimers has been one of the major achievments of the group leading to the publication of the book: NMR of Liquid Crystal Dendrimers, Pan Stanford Publishing Pte. Ltd., Singapore, ISBN 9789814745727, 2017 (Review)

– NMR spectroscopy and relaxometry of ionic liquids

In recent years, ionic liquids (ILs) arose as potential compounds to be used in the development, design and the use of clean technology and materials to reduce or to eliminate the generation and the employ of dangerous substances. The expected main scientific outcomes from the research activities on this topic encompass the description of molecular dynamics, structure and molecular interactions and their influence on macroscopic properties of ionic liquids based systems. The characterization of this type of systems by means NMR spectroscopy and Relaxometry is one the highlights of the group research work. [J. Phys. Chem. B 121, 11472-11484 (2017), Magn. Reson. Chem. 56, 108-112 (2017), New J. Chem. 44, 47 (2017), Phys. Chem. Chem. Phys. 19, 7390 (2017), J. Membr. Sci. 505, 36-43 (2016), J. Phys. Chem. B 120, 5243 (2016), Inor. Chim. Acta 432, 258-266 (2015), J. Phys. Chem. B 119, 11740-11747 (2015)]

– Liquid crytals exhibiting non conventional nematic phases

The study of the recently discovered nematic twist-bend phase od Liquid Crystals is a topical subject due to the expected technological impact in display technology and the fundamental problems related to their chiral phase structure. NMR studies of molecular order and dynamics, combined with electro-optical and magneto-optical techniques, have been applied leading to original results essential to the understanding of the Ntb phase structure. [J. Phys. Chem. B 123, 1442 (2019); Phys. Chem. Chem. Phys. 21, 4523 (2019)].

– Development of Novel Fast Field Cycling NMR Technology

The development of new Fast Field Cycling NMR technology, leading to the construction of a 3rd generation of low power desktop equipments, made possible to diversify and generalize the use of NMR relaxometry to a wide range of materials with both fundamental and technological interest [IEEE Trans. Appl. Supercond. 25, 4301609 (2015); Field-cycling NMR Relaxometry: Instrumentation, Model Theories and Applications , pp. 255, Ed. Rainer Kimmich, The Royal Society of Chemistry, ISBN 978-1-78801-154-9, (copyright year 2019), 2018; Phys. Chem. Chem. Phys. 21, 4523 (2019); Mol. Phys. 117, 975-982 (2019); J. Phys. Chem. B 121, 11472-11484 (2017)].

This equipment, together with the variable field and superconducting magnet NMR spectrometers form an NMR infrastructure unique in Portugal and worldwide competitive in terms of solid state NMR.

New web based user friendly data treatment and analysis software with specific NMR libraries has been devoloped for support and complement of this new technology. Institutional contacts with industrial partners in the field have been established for technology transfer.

– Thin Films and Low Dimensional Quantum Structures

Objectives related to thin films and low dimensional quantum structures include: the application of new dopant predeposition methods at low temperature for the production of CMOS integrated circuits and for a-Si/c-Si heterojunctions of HIT type; the study and application of transparent conductive oxide (TCOs) thin films in sensors, in particular in photodetectors; the deposition of: (0-D) nanospheres of tungsten and molybdenum oxide, (1-D) nanorods of ZnO and ferroelectric NKN, and (2-D) superlattices of (amorphous) a-Si:H/a-SiC:H and (crystalline) GaN/AlGaN.

Foreseen applications are based on higher sensitivity and increased spatial resolution of low dimensional structures e.g. for medical imaging.

[Mater. Sci. Semicond. Process. 42, 210 (2016), Energy Procedia 102, 96 (2016), Proc. EUPVSEC 2017 164(2017), MRS Advances 3, 207 (2018), Thin Solid Films 671, 49 (2019)]