Copper-based nanomaterials have attracted tremendous interest due to their unique properties in the fields of photoluminescence and catalysis. As a result, studies on the correlation between their molecular structure and their properties are of great importance. Copper nanoclusters are a new class of nanomaterials that can provide an atomic-level view of the crystal structure of copper nanoparticles. Herein, a high-nuclearity copper nanocluster with 81 copper atoms, formulated as [Cu81(PhS)46( t BuNH2)10(H)32]3+ (Cu 81 ), was successfully synthesized and fully studied by X-ray crystallography, X-ray photoelectron spectroscopy, hydrogen evolution experiments, electrospray ionization mass spectrometry, nuclear magnetic resonance spectroscopy, and density functional theory calculations. Cu 81 exhibits extraordinary structural characteristics, including (i) three types of novel epitaxial surface-protecting motifs; (ii) an unusual planar Cu17 core; (iii) a hemispherical shell, comprised of a curved surface layer and a planar surface layer; and (iv) two distinct, self-organized arrangements of protective ligands on the curved and planar surfaces. The present study sheds light on structurally unexplored copper nanomaterials and paves the way for the synthesis of high-nuclearity copper nanoclusters.

Bright-red light-emitting diodes (LEDs) with a narrow emission line width that emit between 620 and 635 nm are needed to meet the latest industry color standard for wide color gamut displays, Rec. 2020. CsPbI 3 perovskite quantum dots (QDs) are one of the few known materials that are ideally suited to meet these criteria. Unfortunately, CsPbI 3 perovskite QDs are prone to transform into a non-redemitting phase and are subject to further degradation mechanisms when their luminescence wavelength is tuned to match that of the Rec. 2020 standard. Here, we show that zwitterionic lecithin ligands can stabilize the perovskite phase of CsPbI 3 QDs for long periods in air for at least 6 months compared to a few days for control samples. LEDs fabricated with our ultrastable lecithin-capped CsPbI 3 QDs exhibit an external quantum efficiency (EQE) of 7.1% for electroluminescence centered at 634 nm�a record for all-inorganic perovskite nanocrystals in Rec. 2020 red. Our devices achieve a maximum luminance of 1391 cd/m 2 at 7.5 V, and their operational half-life is 33 min (T 50 ) at 200 cd/m 2 �a 10-fold enhancement compared to control samples. Density functional theory results suggest that the surface strain in CsPbI 3 QDs capped with the conventional ligands, oleic acid and oleylamine, contributes to the instability of the perovskite structural phase. On the other hand, lecithin binding induces virtually no surface strain and shows a stronger binding tendency for the CsPbI 3 surface. Our study highlights the tremendous potential of zwitterionic ligands in stabilizing the perovskite phase and particle size of CsPbI 3 QDs for various optoelectronic applications.

Due to their atomically precise structure, photoluminescent copper nanoclusters (Cu NCs) have emerged as promising materials in both fundamental studies and technological applications, such as bio‐imaging, cell labeling, phototherapy, and photo‐activated catalysis. In this work, a facile strategy is reported for the synthesis of a novel Cu NCs coprotected by thiolate and phosphine ligands, formulated as [Cu15(PPh3)6(PET)13]2+, which exhibits bright emission in the near‐infrared (NIR) region (≈720 nm) and crystallization‐induced emission enhancement (CIEE) phenomenon. Single crystal X‐ray crystallography shows that the NC possesses an extraordinary distorted trigonal antiprismatic Cu6 core and a, unique among metal clusters, “tri‐blade fan”‐like structure. An in‐depth structural investigation of the ligand shell combined with density functional theory calculations reveal that the extended CH···π and π‐π intermolecular ligand interactions significantly restrict the intramolecular rotations and vibrations and, thus, are a major reason for the CIEE phenomena. This study provides a strategy for the controllable synthesis of structurally defined Cu NCs with NIR luminescence, which enables essential insights into the origins of their optical properties.

Precise identification and in-depth understanding of defects in nanomaterials can aid in rationally modulating defect-induced functionalities. However, few studies have explored vacancy defects in ligand-stabilized metal nanoclusters with well-defined structures, owing to the substantial challenge of synthesizing and isolating such defective metal nanoclusters. Herein, a novel defective copper hydride nanocluster, [Cu 36 H 10 (PET) 24 (PPh 3 ) 6 Cl 2 ] (Cu36; PET: phenylethanethiolate; PPh 3 : triphenylphosphine), is successfully synthesized at the gram scale via a simple one-pot reduction method. Structural analysis reveals that Cu36 is a distorted half cubic nanocluster, evolved from the perfect Nichol's half cube. The two surface copper vacancies in Cu36 are found to be the principal imperfections, which result in some structural adjustments, including copper atom reconstruction near the vacancies as well as ligand modifications (e.g., substitution, migration, and exfoliation). Density functional theory calculations imply that the above-mentioned defects have a considerable influence on the electronic structure and properties. The modeling suggests that the formation of defective Cu36 rather than the perfect half cube is driven by the enlargement of the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the nanocluster. The structural evolution induced by the surface copper atom vacancies provides atomically precise insights into the defect-induced readjustment of the local structure and introduces new avenues for understanding the chemistry of defects in nanomaterials.

Polyhydrido copper nanoclusters are an emerging class of nanomaterials. Unfortunately, insights into the structural evolution and structure-property relationship of such copper nanoclusters are scant, due to the difficulty of synthesizing and crystallizing nanoclusters with high nuclearity and new morphologies. Here, we report an anisotropic cuboidal polyhydrido copper nanocluster, [Cu23(PhSe)16(Ph3P)8(H)6]‧BF4, with a distorted cuboctahedral Cu13 core stabilized by two square protecting motifs and six hydrides. The cuboidal nanoclusters self-assemble into a quasi-simple cubic packing pattern with perfect face-to-face contact of neighboring nanoclusters and interdigitation of intercluster surface ligands. Atomic-level observations reveal the crucial role that subtle synergies between nanocluster geometry and intercluster noncovalent interactions play in guiding nanocluster self-assembly. In addition, a comparison with previously reported analogous metal nanoclusters points to bulky monodentate phosphine ligands as a potent inducing agent for the formation of rectangular hexahedral nanoclusters. These findings have significant implications for the controllable synthesis of polyhedral nanomaterials and their superstructures.