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Abstract Oceanic lithosphere, which forms two‐thirds of Earth's surface, is generated at mid‐ocean ridge spreading centers. Yet the internal structure of the lithosphere is not well characterized and often considered to be homogeneous relative to the structure of continental lithosphere. While geophysical observations clearly delineate the crust‐mantle boundary and the lithosphere‐asthenopshere boundary, other seismic anomalies known as mid‐lithosphere discontinuities (MLDs) have been challenging to detect and poorly constrained. Here we present melt transport models applied to the mid‐ocean ridge system that indicate MLDs are a widespread fundamental feature of oceanic lithosphere. In our models, some melt generated from decompression melting is frozen back into the lithosphere, forming a layered refertilization pattern. These refertilized layers are due to the stacked horizontal layering pattern of melt pooling beneath the freezing front. If the recrystallized melt is incorporated into the lithosphere as mafic lenses, the predicted seismic velocity is compatible with observations. 

Abstract Metal halide perovskites show promise for next-generation light-emitting diodes, particularly in the near-infrared range, where they outperform organic and quantum-dot counterparts. However, they still fall short of costly III-V semiconductor devices, which achieve external quantum efficiencies above 30% with high brightness. Among several factors, controlling grain growth and nanoscale morphology is crucial for further enhancing device performance. This study presents a grain engineering methodology that combines solvent engineering and heterostructure construction to improve light outcoupling efficiency and defect passivation. Solvent engineering enables precise control over grain size and distribution, increasing light outcoupling to ~40%. Constructing 2D/3D heterostructures with a conjugated cation reduces defect densities and accelerates radiative recombination. The resulting near-infrared perovskite light-emitting diodes achieve a peak external quantum efficiency of 31.4% and demonstrate a maximum brightness of 929 W sr⁻¹m⁻². These findings indicate that perovskite light-emitting diodes have potential as cost-effective, high-performance near-infrared light sources for practical applications. 

Sodium-ion batteries exhibit significant promise as a viable alternative to current lithium-ion technologies owing to their sustainability, low cost per energy density, reliability, and safety.