W fuzz layers:very high resistance to sputtering under fusion-relevant He+irradiations

In this study,we have modeled the sputtering process of energetic He;ions colliding with W nano-fuzz materials,based on the physical processes,such as the collision and diffusion of energetic particles,sputtering and redeposition.Our modeling shows that the fuzzy nanomaterials with a large surface-to-volume ratio exhibit very high resistance to sputtering under fusion-relevant He;irradiations,and their sputtering yields are mainly determined by the thickness of fuzzy nano0materials,the reflection coefficients and mean free paths of energetic particles,surface sputtering yields of a flat base material,and the geometry of nano-fuzz.Our measurements have confirmed that the surface sputtering yield of a W nano-fuzz layer with the columnar geometry of nano-fuzz in cross-section is about one magnitude of order lower than the one of smooth W substrates.This work provides a complete model for energetic particles colliding with the nano-fuzz layer and clarifies the fundamental sputtering process occurring in the nano-fuzz layer.

Synergistic effect of solvent and solid additives on morphology optimization for high-performance organic solar cells

Controlling the photoactive layer morphology towards nanoscale bi-continuous donor/acceptor interpenetrating networks is a key issue to build high-performance organic solar cells(OSCs).Due to the distinct properties between donor and acceptor materials,casting an active layer from a single solvent solution usually results in either insufficient or excessive phase separation that reduces the device performance.In comparison to the fullerene acceptors with closed-cage structures,the currently dominant non-fullerene acceptors possess the similar anisotropicπ-πinteractions with p-type organic semiconductor donors,giving rise to the complexity of the morphology regulation.Herein,we employ 4,4′-dimethoxyoctafluorobiphenyl(OFP)with strong crystallinity as a volatile solid additive to optimize the active layer morphology of OSCs.The synergistic effect of 1-chloronaphthalene(CN)and OFP as dual additives shows supreme capability on optimizing the morphology over the conventional additive of CN,which is in favor of improving charge transport and suppressing charge recombination for higher fill factors in various systems.In particular,the PTQ10:m-BTP-C6 Ph-based device processed by the additive showed a remarkable powerconversion efficiency(PCE)of 17.74%,whereas the control device processed by CN additive yielded a relatively lower PCE of16.45%.