Since the inception of the atomic force microscope (AFM), dynamic methods (dynamic atomic force microscopy) have been very fruitful by establishing methods to quantify dissipative and conservative forces in the nanoscale and by providing a means to apply gentle forces to the samples with high resolution. Here, we discuss developments that cover over a decade of our work on energy dissipation, phase contrast, and the extraction of relevant material properties from observables.
We describe the attempts to recover material properties via one-dimensional amplitude and phase curves from force models and explore the evolution of these methods in terms of force reconstruction, fits of experimental measurements, and the more recent advances in multifrequency AFM. We further discuss open questions and key possible paths to advance the field
Tuneable and low cost molecular electronics
Advances in dynamic AFM: From nanoscale energy dissipation to material properties in the nanoscale
Sergio Santos, Karim Gadelrab, Chia-Yun Lai, Tuza Olukan, Josep Font, Victor Barcons, Albert Verdaguer, and Matteo Chiesa
The dramatic consequences that the orientation adopted by the molecular dipoles, in diverse arrays of chloroaluminum phthalocyanine (ClAlPc) on Au(111), have on the ulterior adsorption and growth of C60 are explored by means of an all scanning probe microscopy approach. The unidirectional downwards organization of the molecular dipoles at the first layer reduces charge transfer from the metal to C60. Imbalance between attractive and repulsive interactions of the fullerenes are crucial for their ordered supramolecular aggregation.
To date, crystallization studies conducted in space laboratories, which are prohibitively costly and unsuitable to most research laboratories, have shown the valuable effects of microgravity during crystal growth and morphogenesis. Herein, an easy and highly efficient method is shown to achieve space-like experimentation conditions on Earth employing custom-made microfluidic devices to fabricate 2D porous crystalline molecular frameworks.
Layered group V transition-metal trichalcogenides are paradigmatic low-dimensional materials providing an ever increasing series of unusual properties. They are all based on the same basic building units, one-dimensional MX3 (M = Nb, Ta; X = S, Se) trigonal-prismatic chains that condense into layers, but their electronic structures exhibit significant differences leading to a broad spectrum of transport properties, ranging from metals with one, two, or three charge density wave instabilities to semimetals with potential topological properties or semiconductors.
A small library of 2,6- and 3,5-distyrenyl-substituted carborane-BODIPY dyes was efficiently synthesized by means of a Pd-catalyzed Heck coupling reaction. Styrenyl-carborane derivatives were exploited as molecular tools to insert two carborane clusters into the fluorophore core and to extend the π-conjugation of the final molecule in a single synthetic step.
A new compound formed by two antiparallelly disposed tetracyano thienoquinoidal units has been synthesized and studied by electrochemistry and several spectroscopic techniques. Its self-assembly on a Au(111) surface has been investigated by scanning tunneling microscopy.