Inverse heavy-atom effect in near infrared photoluminescent gold nanoclusters

0543233 - ÚOCHB 2022 RIV GB eng J - Journal Article
Pramanik, Goutam - Kvaková, Klaudia - Thottappali, Muhammed Arshad - Rais, David - Pfleger, Jiří - Greben, M. - El-Zoka, A. - Bals, S. - Dračínský, Martin - Valenta, J. - Cígler, Petr
Inverse heavy-atom effect in near infrared photoluminescent gold nanoclusters.
Nanoscale. Roč. 13, č. 23 (2021), s. 10462-10467. ISSN 2040-3364. E-ISSN 2040-3372
R&D Projects: GA ČR(CZ) GA18-12533S; GA MŠMT(CZ) LTAUSA19066
Institutional support: RVO:61388963 ; RVO:61389013
Keywords : excited-state behavior * protected gold * optical properties
OECD category: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect); Polymer science (UMCH-V)
Impact factor: 8.307, year: 2021
Method of publishing: Limited access
https://doi.org/10.1039/D1NR02440J

Fluorophores functionalized with heavy elements show enhanced intersystem crossing due to increased spin–orbit coupling, which in turn shortens the fluorescence decay lifetime (τPL). This phenomenon is known as the heavy-atom effect (HAE). Here, we report the observation of increased τPL upon functionalisation of near-infrared photoluminescent gold nanoclusters with iodine. The heavy atom-mediated increase in τPL is in striking contrast with the HAE and referred to as inverse HAE. Femtosecond and nanosecond transient absorption spectroscopy revealed overcompensation of a slight decrease in lifetime of the transition associated with the Au core (ps) by a large increase in the long-lived triplet state lifetime associated with the Au shell, which contributed to the observed inverse HAE. This unique observation of inverse HAE in gold nanoclusters provides the means to enhance the triplet excited state lifetime.
Permanent Link: http://hdl.handle.net/11104/0320485