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The universal organic pseudohalide treatment applicable to both green and sky-blue LEDs presented in this study promises superior photoluminescence and electroluminescence properties.

Light-emitting diodes (LEDs) are the rapidly developing core components of current display and lighting technology. Metal halide perovskite nanocrystals (MHP NCs) have recently been used as the deep-blue-light-emitting component in LEDs and are considered to have the greatest potential for growth in practical applications. However, the vulnerability of MHP NCs to the environment and the ion migration during the operation of LEDs pose formidable obstacles to the practical application of MHP NCs. Herein, we show that mixed-halide CsPb(Br1-xClx)3 NCs enclosed by epitaxially grown ZnS shells (CPBC/ZnS) are integral to ensuring a stable perovskite-based deep-blue-light-emitting diode (PeLED). We found that epitaxial ZnS shells protect the MHP NCs from the environment, and that the interparticle ion migration between MHP NCs could be effectively suppressed during LED operation, affording an exceptional external quantum efficiency (EQE) of 3.63% at an emission peak of 451 nm and a maximum luminance of 1687 cd m-2. Our results demonstrate that the epitaxial encapsulation of MHP NCs is a powerful strategy for the fabrication of high-efficiency, high-stability PeLEDs with a deep-blue emission.

The curing and adhesion of natural urushiol, a catechol derivative, in water were studied; this work was inspired by the adhesive role of the catechol functional group, found in blue mussels, in water. We confirmed the curing reaction of urushiol in water in the presence of Fe3+ and showed the possibility of utilizing this material as an under-water adhesive. Urushiol becomes the cross-linked network urushi via the formation of chemical and Fe3+-coordination bonds, which were confirmed by FT-IR and Raman spectroscopy. The effect of the coordination bond between the catechol group in urushiol and Fe3+ ion was investigated by mechanical strength measurements. The adhesion strength of urushi formed in an FeCl3 aqueous solution depends on the pH and the thickness; an adhesion strength of 1.4 kgfcm−2 was found at a thickness of 100 μm at acidic condition, revealing a high potential for the applicability of natural urushiol adhesive that has environmental sustainability.