Disentangling size effects and spectral inhomogeneity in carbon nanodots by ultrafast dynamical hole-burning

Sciortino, Alice; Gazzetto, Michela; Buscarino, Gianpiero; Popescu, Radian; Schneider, Reinhard; Giammona, Gaetano; Gerthsen, Dagmar; Rohwer, Egmont J.; Mauro, Nicolò; Feurer, Thomas; Cannizzo, Andrea; Messina, Fabrizio (2018). Disentangling size effects and spectral inhomogeneity in carbon nanodots by ultrafast dynamical hole-burning. Nanoscale, 10(32), pp. 15317-15323. Royal Society of Chemistry 10.1039/c8nr02953a

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Carbon nanodots (CDs) are a novel family of nanomaterials exhibiting unique optical properties. In particular, their bright and tunable fluorescence redefines the paradigm of carbon as a “black” material and is considered very appealing for many applications. While the field keeps growing, understanding CDs fundamental properties and relating them to their variable structures becomes more and more critical. Two crucial problems concern the effect of size on the electronic structure of CDs, and to what extent their optical properties are influenced by structural disorder. Furthermore, it remains largely unclear whether traditional concepts borrowed from the photo-physics of semiconductor quantum dots can be applied to any type of CDs. We used femtosecond optical hole burning to address the excited-state properties of a family of CDs with the specific structure of β-C3N4. The experiments provide compelling evidence of the dramatic effects of structural heterogeneity on the optical spectra, and reveal the remarkably simple pattern of the electronic transitions of these CDs, normally obscured by disorder. Moreover, the data conclusively clarify the different effects of the nanometric size and of the disordered surface structure on the fluorescence tunability, ruling out for these CDs any quantum confinement effect comparable to semiconductor quantum dots.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Applied Physics > NCCR MUST
08 Faculty of Science > Institute of Applied Physics
08 Faculty of Science > Institute of Applied Physics > Lasers

UniBE Contributor:

Sciortino, Alice; Gazzetto, Michela; Rohwer, Egmont Johann; Feurer, Thomas and Cannizzo, Andrea

Subjects:

600 Technology > 620 Engineering
500 Science > 530 Physics
500 Science > 540 Chemistry

ISSN:

2040-3364

Publisher:

Royal Society of Chemistry

Language:

English

Submitter:

Andrea Cannizzo

Date Deposited:

10 Feb 2021 13:34

Last Modified:

10 Feb 2021 13:34

Publisher DOI:

10.1039/c8nr02953a

BORIS DOI:

10.48350/151161

URI:

https://boris.unibe.ch/id/eprint/151161

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