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Title: Isomerization-induced enhancement of luminescence in Au 28 (SR) 20 nanoclusters
Understanding the origin and structural basis of the photoluminescence (PL) phenomenon in thiolate-protected metal nanoclusters is of paramount importance for both fundamental science and practical applications. It remains a major challenge to correlate the PL properties with the atomic-level structure due to the complex interplay of the metal core ( i.e. the inner kernel) and the exterior shell ( i.e. surface Au( i )-thiolate staple motifs). Decoupling these two intertwined structural factors is critical in order to understand the PL origin. Herein, we utilize two Au 28 (SR) 20 nanoclusters with different –R groups, which possess the same core but different shell structures and thus provide an ideal system for the PL study. We discover that the Au 28 (CHT) 20 (CHT: cyclohexanethiolate) nanocluster exhibits a more than 15-fold higher PL quantum yield than the Au 28 (TBBT) 20 nanocluster (TBBT: p-tert -butylbenzenethiolate). Such an enhancement is found to originate from the different structural arrangement of the staple motifs in the shell, which modifies the electron relaxation dynamics in the inner core to different extents for the two nanoclusters. The emergence of a long PL lifetime component in the more emissive Au 28 (CHT) 20 nanocluster reveals that its PL is enhanced by suppressing the nonradiative pathway. The presence of long, interlocked staple motifs is further identified as a key structural parameter that favors the luminescence. Overall, this work offers structural insights into the PL origin in Au 28 (SR) 20 nanoclusters and provides some guidelines for designing luminescent metal nanoclusters for sensing and optoelectronic applications.  more » « less
Award ID(s):
1808675
PAR ID:
10228310
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Chemical Science
Volume:
11
Issue:
31
ISSN:
2041-6520
Page Range / eLocation ID:
8176 to 8183
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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