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Ramírez-Barroso S, Romeo-Gella F, Fernández-García JM, Feng S, Martínez-Fernández L, García-Fresnadillo D, Corral I, Martín N, Wannemacher R. Curved Nanographenes: Multiple Emission, Thermally Activated Delayed Fluorescence, and Non-Radiative Decay. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2212064. [PMID: 37094332 DOI: 10.1002/adma.202212064] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/31/2023] [Indexed: 05/03/2023]
Abstract
The intriguing and rich photophysical properties of three curved nanographenes (CNG 6, 7, and 8) are investigated by time-resolved and temperature-dependent photoluminescence (PL) spectroscopy. CNG 7 and 8 exhibit dual fluorescence, as well as dual phosphorescence at low temperature in the main PL bands. In addition, hot bands are detected in fluorescence as well as phosphorescence, and, in the narrow temperature range of 100-140 K, thermally activated delayed fluorescence (TADF) with lifetimes on the millisecond time-scale is observed. These findings are rationalized by quantum-chemical simulations, which predict a single minimum of the S1 potential of CNG 6, but two S1 minima for CNG 7 and CNG 8, with considerable geometric reorganization between them, in agreement with the experimental findings. Additionally, a higher-lying S2 minimum close to S1 is optimized for the three CNG, from where emission is also possible due to thermal activation and, hence, non-Kasha behavior. The presence of higher-lying dark triplet states close to the S1 minima provides mechanistic evidence for the TADF phenomena observed. Non-radiative decay of the T1 state appears to be thermally activated with activation energies of roughly 100 meV and leads to disappearance of phosphorescence and TADF at T > 140 K.
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Affiliation(s)
- Sergio Ramírez-Barroso
- Department of Organic Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, Madrid, 28040, Spain
- Imdea Nanoscience, C/ Faraday 9, Cantoblanco, Madrid, 28049, Spain
| | | | - Jesús M Fernández-García
- Department of Organic Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, Madrid, 28040, Spain
| | - Siyang Feng
- Imdea Nanoscience, C/ Faraday 9, Cantoblanco, Madrid, 28049, Spain
| | - Lara Martínez-Fernández
- Department of Chemistry, Universidad Autónoma de Madrid, Madrid, 28049, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid, 28049, Spain
| | - David García-Fresnadillo
- Department of Organic Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, Madrid, 28040, Spain
| | - Inés Corral
- Department of Chemistry, Universidad Autónoma de Madrid, Madrid, 28049, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, Madrid, 28049, Spain
| | - Nazario Martín
- Department of Organic Chemistry, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, Madrid, 28040, Spain
- Imdea Nanoscience, C/ Faraday 9, Cantoblanco, Madrid, 28049, Spain
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Xie F, Finney NS. Synthesis and optical properties of mono- and diaminocorannulenes. Chem Commun (Camb) 2020; 56:10525-10528. [DOI: 10.1039/d0cc03853a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A simple synthesis of aminocorannulenes leads to the discovery of surprising properties: tunable visible emission; solid-state fluorescence; water-soluble fluorescent corannulenes.
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Affiliation(s)
- Feifei Xie
- School of Pharmaceutical Sciences and Technology
- Health Sciences Platform
- Tianjin University
- Tianjin
- China
| | - Nathaniel S. Finney
- School of Pharmaceutical Sciences and Technology
- Health Sciences Platform
- Tianjin University
- Tianjin
- China
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