NANOscientific

Search
검색하기
overview
registration
speakers
program
Back to List

Keynote Speaker

Dr. Deepak Venkateshvaran

Optoelectronics, Cavendish Laboratory, University of Cambridge, UK

Feeling the Lattice: AFM as a Real-Space Probe of Charge Transport in Organic Semiconductors

 

Organic semiconductors are prized for their mechanical flexibility, which raises a basic question: does softness limit how well they transport charge? The link turns out to be more intimate than it first appears. Macroscopic stiffness is the long-wavelength, zero-frequency limit of the acoustic phonon response, and the low-energy phonons it reflects are precisely those implicated in charge transport. Mechanics and electronics are therefore not separate properties of these materials but two readings of the same underlying structure.


Atomic force microscopy is the natural tool for probing this link directly, because it captures both molecular order and nanomechanics in real space — on the same
surface, under ambient conditions — as a real-pace counterpart to the reciprocal-space picture from X-ray scattering. I will show how higher-eigenmode imaging resolves polymer packing below one nanometre [1], while force-distance based nanomechanical mapping charts local stiffness across the same regions. Across semicrystalline polymers, nanoscale stiffness tracks structural order [2] — and, more tellingly, stiffness tracks carrier mobility. In the polymer PBTTT, nanomechanical texture evolves across amorphous, terraced, and ribbon phases. In a series based on small-molecule crystals of alkylated DNTT, side chains that expand the unit cell soften the crystal out of plane yet stiffen it in plane, in step with mobility [3].

 

Taken together, these results point to a common structural origin for mechanics and electronics in molecular materials and establish nanomechanical AFM as a tactile complement to scattering — reading structure in real space, where it matters most for transport.


References
[1] I. Dobryden, V. V. Korolkov, … D. Venkateshvaran, Nature Communications 13, 3076 (2022)
[2] S. Cristofaro D. Brandt, … Y. Olivier et al., Journal of Materials Chemistry C 13, 15506 (2025)
[3] K.-H. Hwang, D. Brandt, … D. Venkateshvaran, Nature Communications 17, 1621 (2026)

We use cookies or similar technologies as specified in our privacy policy to enhance your experience.

If you would like to learn more about how we use cookies, click "Cookie Policy".