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The photophysical properties of square planar Pt(II) complexes are often strongly dependent on their self‐assembly modes and intermolecular Pt⋯Pt interactions. Controlling these interactions is important to achieve valuable properties for various applications, such as light‐emitting diodes and environmental sensing devices. Herein, a series of highly luminescent ionic Pt(II) complexes with tunable emission colors are reported, by controlling the molecular structures and interactions in solid state. Four ionic Pt(II) complexes, with a general formula [Pt(C^{^}N)(N^{^}N)]⁺X⁻(C^{^}N = 2‐phenylpyridine or 2‐(2,4‐difluorophenyl)pyridine; N^{^}N = 2,2′‐bipyridine; X⁻= chloride (Cl⁻) or tetraphenylborate (BPh₄⁻), are designed, synthesized, and characterized. Due to the presence of intermolecular Pt⋯Pt interactions, strong metal–metal‐to‐ligand charge transfer (MMLCT) emissions are recorded in all four complexes with color changing from green to deep red in solid state. A high photoluminescence quantum efficiency (PLQE) of 81% is achieved for one of the complexes containing large BPh₄⁻anions, due to the site isolation effects. Detailed structural and photophysical characterizations reveal a clear correlation between the stacking of these Pt(II) complexes and their photophysical properties, which can be well regulated by the molecular structures and counter‐anions.

 

Scintillators, one of the essential components in medical imaging and security checking devices, rely heavily on rare‐earth‐containing inorganic materials. Here, a new type of organic‐inorganic hybrid scintillators containing earth abundant elements that can be prepared via low‐temperature processes is reported. With room temperature co‐crystallization of an aggregation‐induced emission (AIE) organic halide, 4‐(4‐(diphenylamino) phenyl)‐1‐(propyl)‐pyrindin‐1ium bromide (TPA‐PBr), and a metal halide, zinc bromide (ZnBr₂), a zero‐dimensional (0D) organic metal halide hybrid (TPA‐P)₂ZnBr₄with a yellowish‐green emission peaked at 550 nm has been developed. In this hybrid material, dramatically enhanced X‐ray scintillation of TPA‐P⁺is achieved via the sensitization by ZnBr₄²⁻. The absolute light yield (14,700 ± 800 Photons/MeV) of (TPA‐P)₂ZnBr₄is found to be higher than that of anthracene (≈13,500 Photons/MeV), a well‐known organic scintillator, while its X‐ray absorption is comparable to those of inorganic scintillators. With TPA‐P⁺as an emitting center, short photoluminescence and radioluminescence decay lifetimes of 3.56 and 9.96 ns have been achieved. Taking the advantages of high X‐ray absorption of metal halides and efficient radioluminescence with short decay lifetimes of organic cations, the material design paves a new pathway to address the issues of low X‐ray absorption of organic scintillators and long decay lifetimes of inorganic scintillators simultaneously.

 

Platinum( ii ) binuclear complexes containing two platinum centers bridged by different types of ligands have received great research attention for their unique properties and potential applications in a variety of areas. The properties of these binuclear Pt( ii ) complexes, which could be significantly different from those of their mononuclear counterparts, are highly tunable by modifying their cyclometallating ligands and bridging ligands, as well as their structural configurations. The photophysical properties of these complexes involving a wide range of spectroscopic phenomena make them a very interesting class of materials to be spectroscopically studied. Applications of platinum( ii ) binuclear complexes have been explored in several areas, ranging from light emitting diodes, to sensors and photocatalysis. In this review, the molecular structures, photophysical properties, and applications of a variety of platinum( ii ) binuclear complexes are discussed. We intend to shed some light on the recent progress in this field and give a future outlook. 

Metal halide perovskite nanocrystals (NCs) have emerged as new-generation light-emitting materials with narrow emissions and high photoluminescence quantum efficiencies (PLQEs). Various types of perovskite NCs, e.g., platelets, wires, and cubes, have been discovered to exhibit tunable emissions across the whole visible spectrum. Despite remarkable advances in the field of perovskite NCs, many nanostructures in inorganic NCs have not yet been realized in metal halide perovskites, and producing highly efficient blue-emitting perovskite NCs remains challenging and of great interest. Here, we report the discovery of highly efficient blue-emitting cesium lead bromide (CsPbBr 3 ) perovskite hollow NCs. By facile solution processing of CsPbBr 3 precursor solution containing ethylenediammonium bromide and sodium bromide, in situ formation of hollow CsPbBr 3 NCs with controlled particle and pore sizes is realized. Synthetic control of hollow nanostructures with quantum confinement effect results in color tuning of CsPbBr 3 NCs from green to blue, with high PLQEs of up to 81%.