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Abstract Molecular dynamics (MD) simulations are carried out to investigate the effects of the type and spacing of FCC/BCC interfaces on the deformation and spall behavior. The simulations are carried out using model Cu/Ta multilayers with six different types of interfaces. The results suggest that interface type can significantly affect the structure and intensity of the incoming shock wave, change the activated slip systems, alter dislocation slip and twinning behavior, affect where and how voids are nucleated during spallation and the resulting spall strength. Moreover, the above aspects are significantly affected by the interface spacing. A transition from homogeneous to heterogeneous dislocation nucleation occurs as the interface spacing is decreased to 6 nm. Depending on interface type and spacing, damage (voids) nucleation and spall failure is observed to occur not only at the Cu/Ta interfaces, but also in the weaker Cu layer interior, or even in the stronger Ta layer interior, although different mechanisms underlie each of these three distinct failure modes. These findings point to the fact that, depending on the combination of interface type and spacing, interfaces can lead to both strengthening and weakening of the Cu/Ta multilayered microstructures. 

The past few years have witnessed rapid advances in the synthesis of high-quality perovskite nanocrystals (PNCs). However, despite the impressive developments, the stability of PNCs remains a substantial challenge. The ability to reliably improve stability of PNCs while retaining their individual nanometer size represents a critical step that underpins future advances in optoelectronic applications. Here, we report an unconventional strategy for crafting dual-shelled PNCs (i.e., polymer-ligated perovskite/SiO 2 core/shell NCs) with exquisite control over dimensions, surface chemistry, and stabilities. In stark contrast to conventional methods, our strategy relies on capitalizing on judiciously designed star-like copolymers as nanoreactors to render the growth of core/shell NCs with controlled yet tunable perovskite core diameter, SiO 2 shell thickness, and surface chemistry. Consequently, the resulting polymer-tethered perovskite/SiO 2 core/shell NCs display concurrently a stellar set of substantially improved stabilities (i.e., colloidal stability, chemical composition stability, photostability, water stability), while having appealing solution processability, which are unattainable by conventional methods. 

Abstract Instability of perovskite quantum dots (QDs) toward humidity remains one of the major obstacles for their long‐term use in optoelectronic devices. Herein, a general amphiphilic star‐like block copolymer nanoreactor strategy for in situ crafting a set of hairy perovskite QDs with precisely tunable size and exceptionally high water and colloidal stabilities is presented. The selective partition of precursors within the compartment occupied by inner hydrophilic blocks of star‐like diblock copolymers imparts in situ formation of robust hairy perovskite QDs permanently ligated by outer hydrophobic blocks via coprecipitation in nonpolar solvent. These size‐ and composition‐tunable perovskite QDs reveal impressive water and colloidal stabilities as the surface of QDs is intimately and permanently ligated by a layer of outer hydrophobic polymer hairs. More intriguingly, the readily alterable length of outer hydrophobic polymers renders the remarkable control over the stability enhancement of hairy perovskite QDs.