Sulfide-mediated growth of NIR luminescent Pd/Ag atomically precise nanoclusters

Nanoscale. 2024 Dec 12. doi: 10.1039/d4nr04136d. Online ahead of print.

Abstract

An essential feature of coinage metal nanoclusters (NCs) is their photoluminescence (PL), which spans a wide range of wavelengths from visible to near-infrared regions (NIR-I/II). A key challenge for synthetic chemists is to develop materials capable of efficient spectral change with maximum efficiency. Herein, we report novel dithiolate-protected bimetallic Pd-Ag NCs of the type [PdAg16S2{S2P(OR)2}12] (R = iPr, 1Pr and iBu, 1Bu) and [Pd6Ag14S{S2P(OiBu)2}12] (2Bu). Sulfide-mediated expansions of NCs result in unique PL in the NIR-I region for 1Pr and 1Bu (λmax = 808 and 811 nm) and the NIR-II region for 2Pr (λmax = 1007) at 77 K. NIR PL enhancement largely depends on structural modification with the sulfide anions at the central position. DFT calculations indicate that the PL properties are associated with 4dπ(Pd)/3pπ(S) → 5s/5p(Ag) excitation, resulting from the existence of S-Pd(0)-S motifs in both 1 and 2. The electrochemical gaps of 1Pr, 1Bu, and 2Bu are recorded by SWV.