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The simplest and the most efficient deep-red to near-infrared-emitting emitters afford a new record external quantum efficiency for iridium(iii) complex based deep-red to near-infrared organic light-emitting diodes.

Tw o-dimensional (2D) nanomaterials are attracting mucha ttention due to their excellent electronic and optical properties.H ere,w er eport the first experimental preparation of two free-standing mercurated graphyne nanosheets via the interface-assisted bottom-up method, which integrates both the advantages of metal center and graphyne.T he continuous large-area nanosheets derived from the chemical growth show the layered molecular structural arrangement, controllable thickness and enhanced p-conjugation, whichr esult in their stable and outstanding broadband nonlinear saturable absorption (SA) properties (at both 532 and 1064 nm). The passively Q-switched (PQS) performances of these two nanosheets as the saturable absorbers are comparable to or higher than those of the state-of-the-art 2D nanomaterials (suchasgraphene,black phosphorus,MoS 2 , g-graphyne,etc.). Our results illustrate that the two metallated graphynes could act not only as anew class of 2D carbon-richmaterials,but also as inexpensive and easily available optoelectronic materials for device fabrication.

The electrochemical reduction reaction of carbon dioxide (CO 2 RR) to the desired feedstocks with a high faradaic efficiency (FE) and high stability at a high current density is of great importance but challenging owing to its poor electrochemical stability and competition with the hydrogen evolution reaction (HER). Guided by theoretical calculations, herein, a series of novel metalloporphyrin-linked mercurated graphynes (Hg-MTPP) were designed as electrocatalysts for CO 2 RR, since the mercurated graphyne blocks induce a high HER overpotential. Notably, Hg-CoTPP was synthesized and produced a maximum CO FE of 95.6% at −0.76 V (vs reversible hydrogen electrode (RHE)) in an H-type cell, and a CO FE of 91.2% even at −1.26 V (vs RHE), due to a great suppression of HER. The Hg-CoTPP combined with N-doped graphene (Hg-CoTPP/NG) was able to achieve a high CO FE of nearly 100% at a current density of 1.2 A cm −2 and particularly a ground-breaking stability of over 360 h at around 420 mA cm −2 in a flow-type cell. Further experimental and computational results revealed that the mercurated graphyne of Hg-CoTPP brings a high HER overpotential and tunes the d-band electronic states of the metal center that make the d-band center closer to the Fermi level, thus enhancing the bonding of *COOH intermediates on Hg-CoTPP. The introduction of NG could shorten the Co−N coordination bonds, which enhances electron transfer to the metal center to lower the energy barrier for *COOH. Our results illustrated that Hg-MTPP could serve as a new class of two-dimensional (2D) materials and provide a design concept for developing efficient electrocatalysts for CO 2 RR in commercial applications.

Integrating together two dissimilar π-conjugated molecules into controlled complex topological configurations remains a largely unsolved problem owing to the diversity of organic species and their respective different assembly features. Here, we find that two structurally similar organic semiconductors, 9,10-bis(phenylethynyl)anthracene (BA) and 5,12-bis(phenylethynyl)naphthacene (BN), co-assemble into two-component helices by control of the growth kinetics as well as the molar ratio of BA/BN. The helical superstructures made of planar and twisted bis(phenylethynyl) derivatives can be regarded as (BA)x(BN)1−x alloys, which are formed due to compatible structural relationship between BA and BN. Moreover, epitaxial growth of (BA)x(BN)1−x alloy layer on the surface of BA tube to form BA@(BA)x(BN)1−x core-shell structure is also achieved via a solute exchange process. The precise control over composition and morphology towards organic alloy helices and core-shell microstructures opens a door for understanding the complex co-assembly features of two or more different material partners with similar structures.

The dirhodium(II) carboxylate complex Rh2(esp)2 (esp = α,α,α',α'-tetramethyl-1,3-benzenedipropanoate) was shown to catalyze the sulfoxidation of organic sulfides using tert-butyl hydroperoxide as the oxidant. Due to the unique structure of Rh2(esp)2 and its stable Rh2(II,II) catalyst resting state, the rhodium catalyst is able to precipitate as a Rh2(esp)2-sulfoxide complex following the reaction which makes separation of the catalyst from the products very convenient. The precipitated Rh2(esp)2-sulfoxide complexes could be reused to catalyze sulfide oxygenation reactions without considerable loss of activity. Mechanistic studies suggest that the axial ligands fine-tune the redox potential of the dirhodium(II,II) compounds and determine the predominant catalyst species in the oxidation reaction.

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Advances in achieving high external quantum efficiency (EQE) of near‐infrared (NIR) organic light‐emitting diodes (OLEDs) are lagging behind that of the visible‐light OLEDs, according to the energy gap law. Herein, two structurally simple NIR‐phosphorescent Ir(III) complexes, DTCNIr and PTCNIr, with the cyclometalated ligands functionalized by the 1‐phenylisoquinoline‐4‐carbonitrile moiety and thieno/benzo[b]thiophene moiety are handily accessed within three synthetic steps. The introduction of the cyano unit can significantly lower the lowest unoccupied molecular orbitals whereas incorporating the conjugated group can elevate the highest occupied molecular orbitals of the newly designed Ir(III) complexes. The intramolecular charge transfer (ICT) transitions are enhanced due to the increased donor–acceptor interaction inside the metallophosphor. As a result, the emissions are red‐shifted to the NIR region with fast radiative decay. A maximum external quantum efficiency (EQE) of 8.11% with the emission peak at 726 nm for DTCNIr and a maximum EQE of 6.39% with the emission peak at 763 nm for PTCNIr are achieved in the NIR OLEDs by using these Ir(III) materials as the dopant emitters, a champion efficiency in the Ir(III)‐based OLEDs with the emission peak exceeding 760 nm.