Mass Spectrometry as a Preparative Tool for the Surface Science of Large Molecules

Abstract

Measuring and understanding the complexity that arises when nanostructures interact with their environment are one of the major current challenges of nanoscale science and technology. High-resolution microscopy methods such as scanning probe microscopy have the capacity to investigate nanoscale systems with ultimate precision, for which, however, atomic scale precise preparation methods of surface science are a necessity. Preparative mass spectrometry (pMS), defined as the controlled deposition of m/z filtered ion beams, with soft ionization sources links the world of large, biological molecules and surface science, enabling atomic scale chemical control of molecular deposition in ultrahigh vacuum (UHV). Here we explore the application of high-resolution scanning probe microscopy and spectroscopy to the characterization of structure and properties of large molecules. We introduce the fundamental principles of the combined experiments electrospray ion beam deposition and scanning tunneling microscopy. Examples for the deposition and investigation of single particles, for layer and film growth, and for the investigation of electronic properties of individual nonvolatile molecules show that state-of-the-art pMS technology provides a platform analog to thermal evaporation in conventional molecular beam epitaxy. Additionally, it offers additional, unique features due to the use of charged polyatomic particles. This new field is an enormous sandbox for novel molecular materials research and demands the development of advanced molecular ion beam technology.

From Isolated Ions to Multilayer Functional Materials Using Ion Soft Landing

“…[1][2][3][4][5][6][7][8][9][10] Molecular ions are typically delivered to surfaces with kinetic energies in the hyperthermal range (1-100 eV). [1][2][3][4][5][6][7][8][9][10] Molecular ions are typically delivered to surfaces with kinetic energies in the hyperthermal range (1-100 eV).…”

“…Since its introduction by the Cooks group in 1977, [11] ion soft landing has been used predominately for studying uniformly distributed isolated ions on surfaces.T hese studies provided ad etailed understanding of the physical and chemical phenomena accompanying ion deposition, including the structure and reactivity of isolated ions on surfaces,charge retention, covalent-bond formation between ions and functional groups on the surface,s econdary structure,a nd biological activity of soft-landed peptides and proteins.T he progress in this area of ion soft landing research has been extensively reviewed [1][2][3][4][5][6][7][8][9][10] and will not be discussed here. Instead, this Review will focus on an emerging and promising area in this field, in which mass spectrometry is being used to prepare aggregates and multilayer architectures.R ecent developments in ion soft landing instrumentation have resulted in at least an order of magnitude increase in the achievable ion current, which prompted the transition from studying isolated species to more complex multilayer materials.The ability to conduct layer-by-layer ion deposition, which will open up new applications using beams of mass-selected complex ions,r elies on understanding the physicochemical processes accompanying ion-surface collisions.F or example, soft-landed ions often retain their charge and as ubstantial potential may be created on the surface upon the accumulation of ions.…”

Von isolierten Ionen zu mehrschichtigen funktionellen Materialien durch sanfte Landung von Ionen

“…[1][2][3][4][5][6][7][8][9][10] Molekulare Ionen kommen typischerweise mit einer kinetischen Energie im hyperthermalen Bereich (1-100 eV) an Oberflächen an. Diese Fähigkeit veranlasste die Entwicklung der präparativen Massenspektroskopie,b ei welcher nach Masse und Ladung ausgewählte Ionen auf Oberflächen aufgetragen werden.…”

DRILL Interface Makes Ion Soft Landing Broadly Accessible for Energy Science and Applications

“…Soft landing (SL) of ions onto surfaces is a versatile approach for precisely‐controlled preparation of materials for applications and fundamental research in materials, physics, chemistry, and biology . Recent reports have demonstrated the use of SL for preparation of well‐defined model catalysts through deposition of mass‐selected clusters, nanoparticles, and organometallics .…”