Q: Who wrote these Laws of Chemistry and Geometry?
"Photoluminescence (PL) in silver (Ag) nanoclusters (NCs) is intrinsically linked to their structural architecture, yet their low
quantum yield at room-temperature hinders practical applications.
Tokyo University of Science, and the Institute for Molecular Science has revealed that adding a single silver (Ag) atom can profoundly alter how high-nuclear Ag nanoclusters (NCs) emit light.
Their research demonstrated a 77-fold improvement in photoluminescence (PL) quantum yield (QY) at room temperature – a significant achievement that could accelerate the development of next-generation optoelectronic and sensing technologies.
Photoluminescence quantum yield measures how efficiently a material converts absorbed energy into visible light. Enhancing this efficiency directly benefits technologies such as OLED displays used in televisions.
Yet, achieving high PLQY is not as simple as selecting materials with strong luminescence. Silver nanoclusters, for instance, naturally exhibit low PL efficiency, which has limited their practical use despite the extraordinary optical potential they possess.
Both NCs share a common structural framework, with the key
distinction being a single additional Ag atom in the outermost shell ....This addition was achieved through subtle modifications of the surface-protecting ligands, particularly the in-situ generated iPrSO3– group, which created a void within the NC framework that enabled the extra atom’s incorporation. While the core structures remained largely unchanged, the shell modification had profound effects.
In Ag79 NC, the added silver atom enhanced radiative decay rates and a more rigid cluster. The rigidity effectively suppressed non-radiative decay pathways that typically diminish luminescence efficiency. The combination of these factors – enhanced radiative decay from symmetry reduction and reduced non-radiative losses from structural rigidity – enabled the Ag79 NC to exhibit a remarkable 77-fold improvement in PL quantum yield over Ag78 NC at room temperature.
Despite the distinct pathways involved in the formation of templating oxoanions, both Ag78 and Ag79 NCs exhibit a strikingly similar core geometrical arrangement, consisting of 18 Ag(I) atoms.
A: Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding.
Job 38:4
Tokyo University of Science, and the Institute for Molecular Science has revealed that adding a single silver (Ag) atom can profoundly alter how high-nuclear Ag nanoclusters (NCs) emit light.
Their research demonstrated a 77-fold improvement in photoluminescence (PL) quantum yield (QY) at room temperature – a significant achievement that could accelerate the development of next-generation optoelectronic and sensing technologies.
Photoluminescence quantum yield measures how efficiently a material converts absorbed energy into visible light. Enhancing this efficiency directly benefits technologies such as OLED displays used in televisions.
Yet, achieving high PLQY is not as simple as selecting materials with strong luminescence. Silver nanoclusters, for instance, naturally exhibit low PL efficiency, which has limited their practical use despite the extraordinary optical potential they possess.
Both NCs share a common structural framework, with the key
In Ag79 NC, the added silver atom enhanced radiative decay rates and a more rigid cluster. The rigidity effectively suppressed non-radiative decay pathways that typically diminish luminescence efficiency. The combination of these factors – enhanced radiative decay from symmetry reduction and reduced non-radiative losses from structural rigidity – enabled the Ag79 NC to exhibit a remarkable 77-fold improvement in PL quantum yield over Ag78 NC at room temperature.
Despite the distinct pathways involved in the formation of templating oxoanions, both Ag78 and Ag79 NCs exhibit a strikingly similar core geometrical arrangement, consisting of 18 Ag(I) atoms.
--In both cases, the Ag(I) atoms are arranged in an elongated triangular orthobicupola geometry, where their connections form eight triangles and 12 rectangles.
Further evaluation reveals that these Ag(I)-based cationic cores are
intricately encapsulated by a sulfide [S]2– anionic shell, which consists of 15 [S]2– ligands.
--More simply, the structure consists of two triangular cupolas at opposite ends, interconnected by six equatorial rectangular units that act as bridges.
--These equatorial rectangular units play a crucial role in maintaining the overall rigidity of the NCs, ensuring structural integrity under various conditions.
A detailed comparison of the Ag–Ag bond lengths reveals subtle structural differences in the average argentophilic interaction between the two Ag18 cores.
In Ag78 NC, the average Ag–Ag bond length within the Ag18 is 3.192 ± 0.051 Å, while in Ag79 NC, it is slightly shorter at 3.051 ± 0.013 Å.
--This slight contraction in the Ag18 core arrangement indicates subtle structural adjustments, resulting in a minor distortion, likely driven by variations in the coordination of the templating anion with the Ag atoms. In Ag79 NC, the templating anion adopts a μ5 coordination mode with adjacent Ag(I) atoms, resulting in an average Ag–O bond length of 2.611 ± 0.026 Å. In contrast, in Ag78 NC, the anion is coordinated in a μ3 mode, with an Ag–O bond length of 2.635 Å.
Further evaluation reveals that these Ag(I)-based cationic cores are
--This type of encapsulation plays a crucial role in stabilizing the overall structure of Ag NCs by providing a well-defined coordination environment that mitigates electronic repulsions and enhances structural integrity.
Although these [S]2– anions are not intentionally introduced during synthesis in either case, they are generated in situ through the dissociation of respective thiols. However, the spatial distribution of the 15 [S]2– ligands follows a well-defined pattern where 12 [S]2– ligands are positioned on each facet of the triangular cupolas, effectively capping and stabilizing the terminal sections of the cluster core. The remaining three [S]2– ligands are strategically located on alternating rectangular facets in the equatorial region of the core .
“This is the first clear evidence that the incorporation of just one extra silver atom, guided by ligand design, can drastically boost performance,” Professor Negishi explained. “Our findings open a pathway to rationally engineer efficient light-emitting nanoclusters through atomic-level structural modifications.”
“This is the first clear evidence that the incorporation of just one extra silver atom, guided by ligand design, can drastically boost performance,” Professor Negishi explained. “Our findings open a pathway to rationally engineer efficient light-emitting nanoclusters through atomic-level structural modifications.”
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