Specific features of the CuI nanocrystal structure in photochromic glasses

The absorption spectra of CuI nanocrystals with an average radii of 5.3 and 6.2 nm in photochromic glass matrix have been studied in the temperature range 38–300 K. It has been established that the copper iodide nanocrystals, like copper chloride and copper bromide nanocrystals of the same sizes, predominantly crystallize in a nonequilibrium form different from the stable low-temperature cubic modification. The structure of metastable modifications of copper halide nanocrystals in photochromic glasses has been discussed.