A superior mix of big and small: Graphene is often described as an unrolled carbon nanotube. However, although nanotubes are known for their exceptional mechanical and conductivity properties, the same is not true of graphene-based fibers. Xin et al. intercalated small fragments of graphene into the gaps formed by larger graphene sheets that had been coiled into fibers. Once annealed, the large sheets provided pathways for conduction, while the smaller fragments helped reinforce the fibers. The result? Superior thermal and electrical conductivity and mechanical strength. Science , this issue p. 1083

Cs₂SnI_xCl_6−x perovskites were synthesized using hydriodic acid as an iodine source, and the color scheme displays a tunable band gap with varying I⁻/Cl⁻ ratios.