Incorporating synthetic macrocycles with unique structures and distinct conformations into conjugated macrocycle polymers (CMPs) can endowthe resulting materials with great potentials in gas uptake and pollutant adsorption. Here, four CMPs (CMP-n, n = 1-4) capable of reversibly capturing iodine and efficiently separating carbon dioxide are constructed from per-triflate functionalized leaning tower[6]arene (LT6-OTf) and [2]biphenyl-extended pillar[6]arene (BpP6-OTf) via Pd-catalyzed Sonogashira-Hagihara cross-coupling reaction. Intriguingly,o wing to the appropriate cavity sizeo f LT6-OTf and the numerous aromatic rings in the framework, the newly designed CMP-4 possesses an outstanding I 2 affinity with alarge uptake capacity of 208 wt %i nv apor and ag reat removal efficiency of 94 %i na queous solutions.T oo ur surprise,w ith no capacity to accommodate nitrogen, CMP-2 constructed from BpP6-OTf is able to specifically capture carbon dioxide at ambient conditions.
In order to facilitate pyrene (PY) excimer formation in solids, several imidazole-containing PY derivatives were designed and synthesized. Among them, a new compound 1,4,5-triphenyl-2-(pyren-1-yl)-4,5-dihydro-1H-imidazole (IM-PY) was achieved with two crystalline...
2D perovskite single crystals have emerged as excellent optoelectronic materials owing to their unique anisotropic properties. However, growing large 2D perovskite single crystals remains challenging and time‐consuming. Here, a new composition of lead‐free 2D perovskite—4‐fluorophenethylammonium bismuth iodide [(F‐PEA)3BiI6] is reported. An oriented bulk 2D wafer with a large area of 1.33 cm2 is obtained by tableting disordered 2D perovskite powders, resulting in anisotropic resistivities of 5 × 1010 and 2 × 1011 Ω cm in the lateral and vertical directions, respectively. Trivalent Bi3+ ions are employed to achieve a stronger ionic bonding energy with I‐ ions, which intrinsically suppress the ion‐migration effect. Thus, the oriented wafer presents good capabilities in both charge collection and ion‐migration suppression under a large applied bias along the out‐of‐plane direction, making it suitable for low‐dosage X‐ray detection. The large‐area wafer shows a sensitive response to hard X‐rays operated at a tube voltage of 120 kVp with the lowest detectable dose rate of 30 nGy s‐1. Thus, the fast tableting process is a facile and effective strategy to synthesize large‐area, oriented 2D wafers, showing excellent X‐ray detection performance and operational stability that are comparable to those of 2D perovskite single crystals.
Methylammonium lead tribromide perovskite single crystals have been demonstrated to be good candidates as sensitive X-ray detectors in direct detection mode in recent years. However, its X-ray detection performance based on the orientation of different facets is still not clear. Here, we developed a facile strategy to chemically expose the [110] facet of single crystals from low-cost solution processes by tailoring the nonstoichiometry of feeding ions to selectively suppress the growth of the [100] facet. In contrast to physically cutting and sawing single-crystal ingots, this avoids damage to the fragile single crystals as well as orientation errors, more suitable for the naturally soft lattice. Compared to the [100] facet, the exposed [110] facet of perovskite single crystals exhibits a smaller trap density and excellent charge carrier transportation properties, leading to an improved sensitivity of 3928.3 μC/Gy air / cm 2 to 120 keV hard X-rays, which potentially outperforms the currently dominating CsI scintillator of a commercial digital radiography (DR) medical imager for a routine health check.
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