Control of In1-xCrxP (0 ≤ x ≤ 0.09) quantum dot characteristics and luminescence properties via Cr incorporation

The Cr-doped InP quantum dots (In1-xCrxP, 0≤x≤0.09) have been synthesized by a solvothermal method using In and Cr acetylacetonates and tris(1-pyrrolidinyl)phosphine as precursors. A combination of X-ray powder diffraction, transmission electron microscopy (TEM), high resolution TEM along with selected area electron diffraction and energy dispersive spectroscopy demonstrates that the increase of the Cr content in the InP nanocrystals (which is consistent with the increased Cr acetylacetonate loading) leads to a decrease of the quantum dot size, an increase of their monodispersity, and a decrease of lattice constants although the zinc blende InP crystal structure is preserved. The changes in the sizes and structure of the Cr-doped InP quantum dots result in the change of optical properties. The incorporation of Cr into the InP structure allows one to control the band gap of the InP nanocrystals in a wide range and leads to enhanced photoluminescence with high quantum yields. Thus, varying the Cr content one can design the InP quantum dot size and structure as well as their optical properties making it a considerable advance in the development of novel optical materials.