A new variable temperature solution-solid interface scanning tunneling microscope

Abstract

We present a new solution-solid (SS) interface scanning tunneling microscope design that enables imaging at high temperatures with low thermal drift and with volatile solvents. In this new design, distinct from the conventional designs, the entire microscope is surrounded in a controlled-temperature and controlled-atmosphere chamber. This allows users to take measurements at high temperatures while minimizing thermal drift. By incorporating an open solution reservoir in the chamber, solvent evaporation from the sample is minimized; allowing users to use volatile solvents for temperature dependent studies at high temperatures. The new design enables the user to image at the SS interface with some volatile solvents for long periods of time (>24 h). An increase in the nonlinearity of the piezoelectric scanner in the lateral direction as a function of temperature is addressed. A temperature dependent study of cobalt(II) octaethylporphyrin (CoOEP) at the toluene/Au(111) interface has been performed with this instrument. It is demonstrated that the lattice parameters remain constant within experimental error from 24 °C to 75 °C. Similar quality images were obtained over the entire temperature range. We report the unit cell of CoOEP at the toluene/Au(111) interface (based on two molecules per unit cell) to be A = (1.36 ± 0.04) nm, B = (2.51 ± 0.04) nm, and α = 97° ± 2°.

Kinetic and thermodynamic processes of organic species at the solution–solid interface: the view through an STM

“…Molecular self-assembly from solution onto surfaces is widely embraced as a strategy for creating adlayers with desirable electronic, photonic, and chemical properties. 10 Throughout the last two centuries, understanding chemical reactions has included the ability to measure kinetics (rates of reaction) and to measure and/or predict the thermodynamically stable product. If we are to develop a rational method for predicting the surface structures that yield optimal processes, we must understand the fundamentals about how adlayers are formed and react at the solution-solid interface.…”

“…[7][8][9] Very recently an alternative configuration wherein the entire STM exists in a controlled environment has been demonstrated. 10 Throughout the last two centuries, understanding chemical reactions has included the ability to measure kinetics (rates of reaction) and to measure and/or predict the thermodynamically stable product. This competition between kinetics and thermodynamics is a fundamental conflict that underlies all of chemistry.…”

Influence of the Central Metal Ion on the Desorption Kinetics of a Porphyrin from the Solution/HOPG Interface

“…STM has the potential to track single molecules on a time scale of milliseconds to hours and allows one to study the dynamics of monolayer formation on surfaces. As advances in STM continue, new doors open for investigating and understanding various surface phenomena under previously inaccessible conditions. − For example, Jahanbekam et al showed that by enclosing the whole STM body in a controlled chamber one can perform temperature dependent studies on volatile solvents such as toluene (up to at least 75 °C) …”

Polymerization of Physisorbed Molecular Monolayers via Overhanging Alkynyl Chains: Characterization of Polymerization Kinetics and Monolayer Durability

“…Generally, they were flattened and smoothed with a Gaussian 1 filter. High-resolution STM images were corrected for thermal drift as described in a previous study …”