Associate Professor, Department of Chemistry
SL 213 ,
Department of Chemistry
IIT Kanpur,
Kanpur 208016
Molecular Functional Materials
Scanning Tunneling and Atomic Force Microscopy
Surface Science
PhD (2006), Technical University of Chemnitz Germany
M. Sc. (2001) Mahatma Gandhi University
Surface science
Solid state and condensed matter
Near field microscopy
Vacuum techniques
Associate Professor, IIT Kanpur, 2018
Assistant Professor, IIT Kanpur, 2013-2018
Postdoctoral Fellow, Christian-Albrecht University of Kiel, 2008-2013
Postdoctoral Fellow, Chemnitz University of Technology, 2006-2008
National Chemical Laboratory Pune, 2002
Structure and electronic properties of molecules at interface of metal or semiconductor are of great importance in molecular semiconductor industry. The interest on molecular materials is fuelled due to its small size, highly tunable magnetic and electronic properties and plenty of choice. In addition they offer the unique self-assembling property through which one may design any complex structure, even a most complicated design as in animate systems.
Some molecules imitate electronic functionalities like switches, diodes, rectifiers and wires. These molecules -generally called - functional molecules are candidates for future electronic devices based on single molecules. In addition to technological applications the molecules at interface are also of fundamental importance. They do behave different to their bulk counterpart. For example a square planar Fe-porphyrine behave like a square pyramidal structure on Au(111) surface, for which the 5th ligand is the surface itself.
We are investigating molecules on surface, especially functional molecules, using Scanning Tunnelling Microscope (STM) working at solid-liquid interface at ambient condition. STM working at solid-liquid interface offers a real time investigation of structure, dynamics etc. of molecules at interface. Self assembled monolayer of trimesic (TMA) acid is shown in the figure. TMA is a model system that self-assembles on different surfaces. Its self-assembly may be controlled by the nature of the solvent, concentration etc. The figure shows a high density structure of TMA (monolayer) controlled by concentration.
Tunneling spectroscopy is particularly interesting to understand the molecular electronic structure. A multifunctional molecular switch based on azobenzene on Au(111) surface is shown above. Modification of the molecular symmetry upon adsorption is directly reflected in tunneling spectrum.