Bottom-up Synthesis and Functionalization of Graphene Quantum Dots with Atomically Precise Structures

Akimitsu Narita^a^,^b

^aOkinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna, Japan

^bMax Planck Institute for Polymer Research, Mainz, Ackermannweg, 10, Mainz, Germany

Materials for Sustainable Development Conference (MATSUS)
Proceedings of nanoGe Spring Meeting 2022 (NSM22)

#LowEnOpto22. Low-dimensional Semiconductors for Energy and Optoelectronic Research: a Journey from 0 to 2D

Online, Spain, 2022 March 7th - 11th

Organizers: Ilka Kriegel, Teresa Gatti and Francesco Scotognella

Invited Speaker, Akimitsu Narita, presentation 105
DOI: https://doi.org/10.29363/nanoge.nsm.2022.105
Publication date: 7th February 2022

Graphene quantum dots (GQDs) and carbon dots (CDs) have been attracting research attention as carbon-based and environmentally friendly alternative of the inorganic semiconductor quantum dots. Similar to their inorganic counterpart, GQDs and CDs demonstrate promising optical properties with emission wavelength dependent on their sizes. However, their precise chemical structures are unknown and uncontrollable in most of the cases, which makes it difficult to fine-tune the properties or establish the structure-property relationship. To this end, the methods of synthetic organic chemistry provide the bottom-up approach to obtain GQDs with atomically precise structures, namely large polycyclic aromatic hydrocarbons (PAHs) that are also called nanographenes [1]. We have synthesized dibenzo[hi,st]ovalene (DBOV) as a molecular GQD with a combination of armchair and zigzag edges, which demonstrated strong red emission and stimulated emission [2]. Regioselective bromination of DBOV could be established, enabling the edge-functionalization to install various functional groups for the fine-tuning of the optical and electronic properties [3]. For example, fluoranthene imide groups were attached to DBOV, which led to red-shifted emission with larger Stokes shift [4]. The π-extension of DBOV was achieved through Pd-catalyzed alkyne benzannulation, affording circumpyrene as GQD with multiple zigzag edges [5]. On the other hand, nitrogen-doped DBOV showed acid- and metal-sensitive fluorescence, indicating its potential for sensing applications [6]. We have more recently also synthesized a wider variety of functionalized DBOVs as well as novel GQDs, providing further insights into the structure-property relationship. These results highlight the high potential of molecular GQDs for a wide range of applications in the optoelectronics and photonics.

References:

[1] Paternò, G. M.; Goudappagouda; Chen, Q.; Lanzani, G.; Scotognella, F.; Narita, A., Large Polycyclic Aromatic Hydrocarbons as Graphene Quantum Dots: from Synthesis to Spectroscopy and Photonics. Adv. Optical Mater. 2021, 2100508.

[2] Paternò, G. M.; Chen, Q.; Wang, X.-Y.; Liu, J.; Motti, S. G.; Petrozza, A.; Feng, X.; Lanzani, G.; Müllen, K.; Narita, A.; Scotognella, F., Synthesis of Dibenzo[hi,st]ovalene and Its Amplified Spontaneous Emission in a Polystyrene Matrix. Angew. Chem. Int. Ed. 2017, 56, 6753-6757.

[3] Chen, Q.; Wang, D.; Baumgarten, M.; Schollmeyer, D.; Müllen, K.; Narita, A., Regioselective Bromination and Functionalization of Dibenzo[hi,st]ovalene as Highly Luminescent Nanographene with Zigzag Edges. Chem. Asian J. 2019, 14, 1703–1707.

[4] Paternò, G. M.; Chen, Q.; Muñoz-Mármol, R.; Guizzardi, M.; Bonal, V.; Kabe, R.; Barker, A. J.; Boj, P. G.; Chatterjee, S.; Ie, Y.; Villalvilla, J. M.; Quintana, J. A.; Scotognella, F.; Müllen, K.; Díaz-García, M. A.; Narita, A.; Lanzani, G., Excited states engineering enables efficient near-infrared lasing in nanographenes. Mater. Horiz. 2021, Advance Article.

[5] Chen, Q.; Schollmeyer, D.; Müllen, K.; Narita, A., Synthesis of Circumpyrene by Alkyne Benzannulation of Brominated Dibenzo[hi,st]ovalene. J. Am. Chem. Soc. 2019, 141, 19994-19999.

[6] Jin, E.; Yang, Q.; Ju, C.-W.; Chen, Q.; Landfester, K.; Bonn, M.; Müllen, K.; Liu, X.; Narita, A., A Highly Luminescent Nitrogen-Doped Nanographene as an Acid- and Metal-Sensitive Fluorophore for Optical Imaging. J. Am. Chem. Soc. 2021, 143, 10403-10412.

Acknowledgements:

This work was financially supported by the Max Planck Society, the Okinawa Institute of Science and Technology Graduate University, the FLAG-ERA Grant OPERA by DFG 437130745, the ANR-DFG NLE Grant GRANAO by DFG 431450789, and JSPS KAKENHI Grant No. JP19K24686.

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