Abstract: Disclosed herein are lattice-anchored materials that combine cesium lead halide perovskites with lead chalcogenide colloidal quantum dots (CQDs) that surprisingly exhibit stability exceeding that of the constituent materials. The CQDs keep the perovskite in its desired cubic phase, suppressing the transition to the undesired, lattice-mismatched, phases. These composite materials exhibit an order of magnitude enhancement in air stability for the perovskite, showing greater than six months' stability in room ambient as well as being stable for more than five hours at 200° C. in air. The perovskite prevents oxidation of the CQD surfaces and reduces the nanoparticles' agglomeration under 100° C. by a factor of five compared to CQD controls. The matrix-protected CQDs exhibit 30% photoluminescence quantum efficiency for a CQD solid emitting at infrared wavelengths.