seminars

Charge transport at Electrode-Molecule interface: From Molecular Electronics to energy research applications

Physical and Analytical Chemistry Seminar

Lecturer: Dr. V. Kaliginedi

Date:
28-28 Oct 2018 @ 12:30

Location: Faculty Seminar Room

Abstract:

The idea of building electronic devices using single molecule as an active component was first proposed by Aviram and Ratner in the early seventies.1 Indeed, molecules are of great interest for application in electronic devices because of their small size, recognition properties, ability of self-organization, possibility of chemical modification and customisation. Thus, the ability to measure and control charge transport across metal|molecule|metal junction at single molecule level is of considerable fundamental interest and represents a key step towards the development of molecular electronic and spintronics devices.2-6 In addition to the applications in molecular electronics and spintronics research, studying charge or electron transport properties at metal|molecule interfaces under the influence of external stimuli like light, temperature, electrochemical potential or magnetic field will have a variety of applications in other research fields like (i) energy research (for example, solar cells, where the charge or electron transfer at metal|molecule interfaces plays a crucial role in determining the efficiency of the solar cell); (ii) photocatalysis and electrocatalysis (activity of a catalyst depends on the effective charge transport at electrode|catalyst interface); (iii) Sensors (sensitivity and selectivity of a sensor may depend on the effective charge transport at electrode|sensor moiety interface) and etc.5,7 Thus, the possibility of studying the properties of molecules or nanostructures at single entity level offers huge opportunities to tune structure property relationships at nanoscale. The problem with current state-of-the-art nanomaterials and energy research involving charge or electron transport at electrode|molecule interface as a key process is centered in the fact that no single experimental technique can independently provide complete information on nanoscale structure-property relationships. The development of fast, cost effective and structure sensitive characterization methods at single entity level is the target of much current nanotechnology research.

In the first part of my presentation, I will introduce working principle of measurement techniques (i.e STM break junctions (STM-BJ), mechanically controllable break junction (MCBJ)) and data analysis procedures used to extract conductance properties of single molecular junctions.2 Using the results from several case studies, I will try to demonstrate structure-property correlations of metal|molecule|metal junctions at single and multi-molecular level.2-6 In the later part of my presentation, I will try to show the experimental framework (experimental technique and methodologies development) that I am planning to implement/develop in my future laboratory to address the key issue of nanoscale structure-property relationships under the influence of external stimuli.3,5,7

 

References:

  1. Aviram, A.,Ratner, M., Chem. Phys. Lett. 1974, 29, 277.
  2. Kaliginedi et al., Journal of American chemical society. 2012, 134, 5262–5275.
  3. Rudnev, A., Kaliginedi et al., Science Advances. 2017, 3, e1602297.
  4. Seth, C., Kaliginedi et al., Chemical Science. 2017, 8, 1576-1591.
  5. Atesci, H., Kaliginedi et al., Nature Nanotechnology. 2018, 13, 117.
  6. Kaliginedi et al., PCCP. 2015, 16, 23529.
  7. Kaliginedi et al., Nanoscale. 2015, 7, 17685.