Group of Physical Chemistry of Surfaces and Interfaces, ICMAB-CSIC

Group type: Experiment

Research description: The group started up its activity at the ICMAB in 2007, with the arrival of C. Ocal at this institute, and expanded its scientific interests with the incorporation of E. Barrena in 2010. Nowadays, our research is focused on unraveling the nanoscale structural and physical-chemical properties of nanostructures and interfaces, spanning from fundamental issues in organic growth to the electronic response of metal-organic junctions. We have always payed special attention to the customized design of experimental methodologies.

An important part of our investigation centers on surface functionalization by self-assembled monolayers (SAMs), including micro-contact printing (m-CP), and the study of organic semiconductors with relevance as active layers for electronic devices, such as organic solar cells (OSC) and field effect transistors (OFETs). We accomplish our objectives within an experimental approach in which sample preparation through surface engineering is combined with nanoscale surface characterization and, eventually, correlated to macroscopic measurements in operating devices. This strategy allows us to get improved understanding on device operation in relation to thin-film micro-structure. In this regard, we use Kelvin Probe Force Microscopy (KPFM) to map the electrical potential within the OFETs channel during operation and obtain contact resistances, mobility or localized trap states within the channel, which are among the most important issues yielding to significant progress in these devices.

We employ Scanning Probe Microscopes (SPM) beyond imaging to gain insight into mechanical (AFM), tribological (FFM) and electronic/electrical properties (STM, C-AFM, KPFM) with nanoscale resolution. The group counts with a SPM laboratory and an STM/nc-AFM equipment in ultra-high-vacuum (UHV) installed since 2011 in the Spanish synchrotron facility ALBA within a specific agreement. When required, we use synchrotron facilities to obtain complementary chemical or structural characterization, in particular grazing incidence X-ray diffraction (GIXD) to study the structural evolution during growth or access to the structure of buried interfaces.