EXCITON SPECTRA OF SNO2 NANOCRYSTALS WITH SURFICIAL DIPOLE LAYER

Experimental results of absorption, luminescence and excitation spectr a in both bare and coated SnO2 nanocrystals are given. It is found tha t when the SnO2 nanocrystals are coated by a layer of organic molecula e, the absorption edge shifts to the longer wavelength direction as th e particle size decreases, which is inconsistent with that of bare SnO 2 nanocrystals. It is demonstrated that the size and surface situation s of nanocrystals have great influence on their spectroscopic properti es. The experimental data are discussed in terms of the quantum confin ement effects and dielectric confinement effects.