Versatile Graphene Nanoribbons and Quantum Chiral Nanocarbons

Date

Jan 11, 2024

Time

12:00 PM - 2:00 PM

Speaker

Wenhui Niu

Affiliation

Max Planck Institute of Microstructure , Halle

Series

TUD nanoSeminar

Language

en

Main Topic

Materialien

Other Topics

Materialien

Host

Arezoo Dianat

Description

In the first of the talk, we will focus on the topological engineering of graphene nanoribbons (GNRs) with tailor-made optoelectronic properties. GNRs, as quasi-one-dimensional graphene cutouts, have drawn growing attention as promising candidates for next-generation electronic and spintronic materials. However, the strong π-π interaction of GNRs prevents liquid-phase dispersibility, corresponding to severe aggregates with bad dispersibility in organic solvents, which significantly impedes their fundamental physiochemical studies as well as promising applications in nanoelectronics. To improve the dispersibility and to engineer the optoelectronic properties of GNRs, here we have developed the strategy of topological engineering of GNRs and synthesized a series of novel GNRs including bulky group functionalized GNR, porous GNR and curved GNR which present interesting properties and hold great potential in nanoelectronics devices.
 In the second of the talk, we will focus on the chiral nanocarbons with unique chiroptical properties as well as interesting spin polarization. Chiral nanocarbons have attracted growing attention due to their exotic 3D structure, inherent chirality, and intriguing optoelectronic properties, in particular, their unique chiral-induced spin selectivity (CISS) effect. Due to the unique structural tunability and the specificity of quantum sensing, chiral nanocarbons have the potential to be a transformative tool in the next generation of quantum applications. Among them, helical nanographenes (NGs) featuring multi-layer topology have been considered as promising candidates for understanding the intricate interplay between the chiral structure and chiroptical properties/spin polarization. Herein, we demonstrate the modular synthetic strategy to construct a series of novel helical NGs with bilayer, trilayer, and tetralayer structures. The resultant NGs exhibit excellent circular dichroism (CD) and circularly polarized luminescence (CPL) responses with unprecedented high CPL brightness, rendering them promising candidates for CPL emitters. More interestingly, with the cooperation with Prof. Ron Naaman’s group, the magnetoresistance (MR) measurements were performed to investigate the spin polarization of our chiral molecules, which proves the clear CISS effect of our helical NGs.

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Last modified: Jan 12, 2024, 7:37:04 AM