The collective optical response of distinctive component particles can lead to a broad infrared spectral region with near-zero real permittivity (epsilon near zero, ENZ) in nanocrystalbased metasurfaces (Figure ). The real component of the effective permittivity (Re(ϵ eff )) approaches zero when the average nanocrystal dipole moment has a small negative value, counteracting the small positive permittivity of the background medium (shaded region in Figure ). For a homogeneous superlattice (Figure ), all particles resonate in the same direction, and ENZ appears only in the small frequency regions where all the dipoles flip sign. In contrast, in the mixed superlattices, the dipole moments of each nanoparticle type have opposite signs and counteract one another over a broad range of frequencies, resulting in an extremely broad frequency range where the mixed superlattice behaves as an ENZ metamaterial (Figure ).