Composites having semiconductor structures embedded in a matrix are described. In an example, a composite includes a matrix material. A plurality of semiconductor structures is embedded in the matrix material. Each semiconductor structure includes an anisotropic nanocrystalline core composed of a first semiconductor material. Each semiconductor structure also includes a nanocrystalline shell composed of a second, different, semiconductor material at least partially surrounding the anisotropic nanocrystalline core. An insulator layer encapsulates each nanocrystalline shell and anisotropic nanocrystalline core pairing.