ABSTRACT
Semiconductor nanocrystals whose radii are smaller than the bulk exciton Bohr radius, or quantum dots (QDs), constitute a new class of materials intermediate between molecular and bulk forms of matter. The density of states of semiconductor QDs is similar to the atomic density of states. To improve the luminescence quantum efficiency, a growing of a thin inorganic shell of the wide-band gap semiconductor around the particles had been proposed. The photoluminescence (PL) properties of the QD-polyvinyl alcohol (PVA) composite containing QDs produced in gelatine and embedded in PVA film without adding HCl are similar to those of the QD-gelatine. Embedding colloidal QDs in a polymer matrix is another way to increase the quantum efficiency of their luminescence, since polymer passivates the defects on the QDs' surface and protects against moisture and oxygen, which plays an important role in the degradation of QDs. To increase the concentration of QDs in polymer matrix, special routes are necessary.
