Long persistence phosphors are promising materials for energy‐saving applications, due to their ability to temporarily store and release light. While boron is known to dramatically extend the afterglow persistence to longer than 8 h in strontium aluminates, previous attempts to understand the role of boron neglected any nanoscale‐related effects and have been inconclusive. Herein, nanoscale‐resolved cathodoluminescence mapping is correlated with selected area electron diffraction and with energy dispersive x‐ray spectroscopy analysis using a 2 Å‐diameter probe. The salient aspect of this unique approach is that one can not only determine the elemental distribution in the phosphor microstructure, but more importantly, one can discriminate between the distributions of different divalent and trivalent luminescing ions. We demonstrate that the extremely long afterglow is due to the boron dopant via two key roles: (1) facilitating dominance of the long persistence phase during the microstructural evolution and (2) promoting more uniform distribution of the optically active, Eu2+ ion in the Sr2+ cation sublattice.
Current trends in data processing have given impetus for an intense search of new concepts of memory devices with emphasis on efficiency, speed, and scalability. A promising new approach to memory storage is based on resistance switching between charge-ordered domain states in the layered dichalcogenide 1T-TaS 2 . Here we investigate the energy efficiency scaling of such charge configuration memory (CCM) devices as a function of device size and data write time τ W as well as other parameters that have bearing on efficient device operation. We find that switching energy efficiency scales approximately linearly with both quantities over multiple decades, departing from linearity only when τ W approaches the ∼0.5 ps intrinsic switching limit. Compared to current state of the art memory devices, CCM devices are found to be much faster and significantly more energy efficient, demonstrated here with two-terminal switching using 2.2 fJ, 16 ps electrical pulses.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.