Optical properties of alkali doped group IV nano materials

Optical properties of sodium and other alkali metals (lithium & potassium) incorporated into nano hosts of group IV elements (carbon, silicon & germanium) were investigated as candidates for solid state light emitting materials. First, optical properties were calculated by quantum mechanical simulations using TDDFr method. Results of the simulation indicate that alkali doped group 4 nano hosts exhibit optical transitions in and around the visible whereas, undoped nano hosts do not have any at sinfflar wavelengths. Some combinations of alkali dopant and nano host give rise to multiple transitions in the visible. One of the simulated combinations, Li dopant and carbon nano host was synthesized for experimental verification. Optical absorption and emission characteristics of the synthesized material were measured and compared with those obtained from quantum mechanical calculations. Both the wavelength and the relative intensity of the measured optical transitions were found to be in good agreement with the results of the calculations. Alkali metals which have good light emission characteristics can be combined with group IV indirect sen-dconductors to obtain new nano materials which have interesting optical properties in the visible.