Scientists Make Silver Glow 77× Brighter

A team of Japanese researchers discovered that adding just one silver atom to a nanocluster can boost its light-emitting efficiency by 77 times.

A collaborative team from Tohoku University, 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. The study was recently published in the Journal of the American Chemical Society.

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.

Designing and Comparing Silver Nanoclusters

To probe the structure-property relationship in greater detail, the team synthesized and compared two closely related anion-templated Ag NCs: [SO₄@Ag₇₈S₁₅(CpS)₂₇(CF₃COO)₁₈]⁺: Ag₇₈ NC (CpS: cyclopentatethiolate), [SO₄@Ag₇₉S₁₅(ⁱPrS)₂₈(ⁱPrSO₃)₁₅(CF₃COO)₄]: Ag₇₉ NC (ⁱPrS: iso-propyl thiolate). Both NCs share a common structural framework, with the key distinction being a single additional Ag atom in the outermost shell of Ag₇₉ NC.

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.

Toward a New Generation of Light-Emitting Materials

“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.”

With this new advancement, researchers anticipate new opportunities for deploying silver nanoclusters in high-performance light-emitting devices, bioimaging, and catalytic systems, where efficient luminescence at room temperature is critical.

Reference: “Triggering Photoluminescence in High-Nuclear Silver Nanoclusters via Extra Silver Atom Incorporation” by Aoi Akiyama, Sakiat Hossain, Sourav Biswas, Takafumi Shiraogawa, Pei Zhao, Mana Nakamoto, Daiji Ogata, Tokuhisa Kawawaki, Yoshiki Niihori, Junpei Yuasa, Masahiro Ehara and Yuichi Negishi, 30 September 2025, Journal of the American Chemical Society.
DOI: 10.1021/jacs.5c10289

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