Painting on the cool: Passive radiative cooling materials emit heat. They can reduce the need for air conditioning by providing daytime cooling but are often challenging to apply to rooftops and other building surfaces. Mandal et al. fabricated porous poly(vinylidene fluoride-co-hexafluoropropene) to create an excellent radiative cooling material. Better yet, the polymer is easy to paint or spray onto a wide range of surfaces, has good durability, and can even be dyed. This makes it a promising candidate for widespread use as a high-performance passive radiative cooling material. Science , this issue p. 315

A simple, inexpensive, and paintable bilayer coating approach enables both color and efficient cooling.

Broadband thermal beaming: Thermal radiation emits over a wide range of wavelengths and over a wide range of angles. Xu et al. constructed a material that allows a range of wavelengths to emit over a much narrower range of angles. This property allowed the authors to beam thermal energy preferentially in one direction. The strategy requires carefully exploiting stacks of epsilon-near-zero films in which the angular range of thermal emission is controlled by the film thickness. This design could be useful in thermal camouflage and passive radiative cooling applications. Science , this issue p. 393