Surface states (SS) have a great impact on photoluminescent prope1iies of quantum dots (QD). In order to reduce the influence of surface states, quantum dots are passivized by chemical route, or covered with shell of semiconducting material with a larger band 2.1"10' gap. We compare manifestation of QD surface states in 1.8-3.4nm size range. We use a one-pot approach to synthesize -'9.0x10' CdSe NCs within the size range of 1.84 - 3.4 nm at mild temperature (85-150 °C) and CdSe/ZnS core-shell. With the size control that can be achieved for CdSe QDs, the capping of lower band­ wavelength, nm Fig. I. Absorbance and luminescence spectra of CdSe gap (CdSe) core nanocrystals with a higher band-gap (ZnS) shells is an attractive possibility that leads to the core/shell QDs 2-CdSe/ZnS with improved luminescence, higher stability [1]. We have studied CdSe quantum dots thin films, obtained by "drop cast" method. Luminescence excitations were perfo1med with nitrogen laser (Aex .... 0,5 =337,1 run). Quantum dots dimensioned 2,57nm±5,3%; 2,9nm±5,2%; 3,4nm±5%, 0,0 also "magic size" dimensioned 1,84nm±l ,2% and 2,04run ±1,2% have Fig.2 Absorbance and luminescence spectra of "magic­ photoluminescence (PL) and UV-VIS size" CdSe and CdSe/ZnS QDs. absorbance spectra of typical quantum dots low-intensity PL peak situated at long wavelengths is pointing out the existence of non-passivated surface states. Absorbance and luminescence spectra of "magic size" quantum dots are shown in Fig. 2. NaITow absorbance bands with minimum at 435 nm and 462 run proves that we are dealing with (CdSe)33 and (CdSe)34 clusters [2]. The excitonic luminescence is almost inhibited by intensive luminescent band of surface states (HWHM=78 run). The shape of spectra is maintained after shelling CdSe cores with ZnS (Fig.2), slightly enhancing the quantum yield (30 %). The wide wavelength luminescent band is saved due to change of quantum dots surface prope1iies at transition to "magic size" independent of "core" or "core/shell" structures due to the1modynamically favorable magic size structures.