Studies on self-assembly of metal nanoclusters (MNCs) are an emerging field of research owing to their significant optical properties and potential applications in many areas. Fabricating the desired self-assembly structure for specific implementation has always been challenging in nanotechnology. The building blocks organize themselves into a hierarchical structure with a high order of directional control in the self-assembly process. An overview of the recent achievements in the self-assembly chemistry of MNCs is summarized in this review article. Here, we investigate the underlying mechanism for the self-assembly structures, and analysis reveals that van der Waals forces, electrostatic interaction, metallophilic interaction, and amphiphilicity are the crucial parameters. In addition, we discuss the principles of template-mediated interaction and the effect of external stimuli on assembly formation in detail. We also focus on the structural correlation of the assemblies with their photophysical properties. A deep perception of the self-assembly mechanism and the degree of interactions on the excited state dynamics is provided for the future synthesis of customizable MNCs with promising applications.

Subnanometer-sized metal nanoclusters (NCs) with diameters <2 nm have emerged as promising materials in biomedical applications. Here, we report the synthesis of near-infrared (NIR)-emitting Au 14 nanoclusters using a small therapeutic molecule, D-penicillamine (DPA), as a surface stabilizing agent. We have characterized the morphology and composition of as-synthesized NCs using electron microscopy and mass spectrometry techniques. The photophysics of the NCs was investigated by UV−vis and photoluminescence (PL) spectroscopy. We found molecule-like features with three distinctive absorption bands at 390, 456, and 590 nm and a photoemission band at 696 nm. We observed that Au NCs specifically inhibited cancer cells dose-dependently through preferential uptake and imparted significant intracellular ROS. They did not show any acute toxicity in C57BL/6 mice at a dosage of 10 mg/kg, with predominant accumulation in the kidneys at the end of 24 h.

The generation of green hydrogen via electrocatalytic water splitting is an emerging strategy in the prospect of developing future energy devices. Herein, we designed water-soluble atomically precise Ni nanoclusters (NCs) on MoSe2 nanosheets (NSs) to enhance the hydrogen evolution reaction (HER) performance. The strong UV–vis absorption band and matrix-assisted laser deposition ionization (MALDI) time-of-flight mass spectra confirm the formation of Ni7 NCs. The energy-dispersive X-ray spectroscopy mapping confirms the homogeneous distribution of Ni, Mo, and Se throughout the surface of the ultrathin NS. X-ray photoelectron spectroscopy study reveals the strong interfacial interaction between Ni NCs and MoSe2 in the nanocomposite by substantial electron density transferring from Ni NCs to the MoSe2 NSs. It is seen that the 5 wt % Ni/MoSe2 composite structure exhibits the most notable HER efficiency with an overpotential of 170 mV vs reversible hydrogen electrode @ 10 mA/cm2 which is significantly lower than that of bare MoSe2 NSs (350 mV). The significantly lower Tafel slope of the Ni/MoSe2 nanocomposite indicates that the HER kinetics of MoSe2 is accelerated in the presence of Ni NCs. The charge-transfer resistance of the nanocomposite is significantly low compared to pristine MoSe2, confirming the enhanced interfacial charge transfer. This work opens up further opportunities to design efficient and low-cost electrocatalysts for improving the HER performance by incorporating the advantages of both non-precious atomically precise metal NCs and transition-metal dichalcogenides in one system.

Bimetallic nanoclusters (NCs) have emerged as a new class of luminescent materials for potential applications in sensing, bio-imaging, and light-emitting diodes (LEDs). Here, we have synthesized copper-gold bimetallic nanoclusters (AuCu...

The sensitive and selective detection of sulfide (S2–) ions in water is of major interest due to its toxicity and physiological effects on organisms. Herein, we have designed a fluorescent probe, poly(allylamine) hydrochloride (PAH) functionalized copper nanocluster (Cu NC@PAH), for the detection of S2– ions. The synthesis of the probe is based on the electrostatic interaction between negatively charged Cu NCs and the positively charged polymer, PAH. The drastic enhancement of the photoluminescence (PL) intensity of Cu NCs and the quantum yield (QY) enhancement from 0.3 to 6% are evident after functionalizing with a cationic polymer matrix of PAH. The steady-state and time-resolved fluorescence studies support the aggregation-induced emission (AIE) phenomenon for PL QY enhancement. In addition, the Cu NCs@PAH exhibit excellent selectivity toward aqueous S2– ions. The probe displays a reasonable quenching response for S2– ions over a concentration range of 0–20 μM with a detection limit of 2.39 μM. We believe that this facile and economical synthesis methodology of Cu NCs@PAH with interesting AIE properties will extend the scope of previously available techniques for the detection of the S2– ion.