ZnS:Cu nanocrystals were synthesized in polymeric networks. X-ray photoemission spectroscopy and atomic absorption data show that the Zn and Cu ion mass contents were about 8.2% and 0.12%, respectively. The particle size of ZnS:Cu nanocrystals was about 3.0 nm, measured by UV-vis spectrum. Due to the quantum size effects, the band gap energy of ZnS nanocrystals was about 4.2 eV. Compared with the photoluminescence of ZnS which peaks at 390 nm, the photoemission of ZnS:Cu/polymer thin films was peaking at 415 nm because of Cu acting as luminescent centers. The ZnS:Cu/polymer was also used to fabricate light-emitting diode (LED), as the emitting layer of LED, the blue light of electroluminescence was observed at room temperature, and its turn-on voltage was less than 4 V.

The hexagonal ZnS nanocrystals were synthesized in polymer matrix. The ZnS polymer composite doped with tetraphenylbenzidine (TPB) as light-emitting layer was used to fabricate a single layer structure light-emitting diode which has a low turn on voltage such as 2.5 V. The electroluminescence spectrum was obtained at room temperature. Owing to the effect that TPB interacted with ZnS nanocrystal to form the luminescent center, the emission was peaking at 520 nm which shifts to the lower energy compared with that of ZnS, and the half-width of the emission was about 20 nm.

The polymer electroluminescence (EL) device m'th PBD as carriers confinement layer yields bright blue emission having intensity of 300cd/m2, in same case the device without PBD layer have luminance only 44 cd/m2. The effect of PBD layer on EL characteristic was studied. The results 8how that only in EL devices with PBD thickness over 30nm, the holes are completely confined in emitting layer. The luminance over 2000cd/m2 can be obtained by inserting an electron iqjecting layer between the negative electrode and PBD to increase the electron injection.

Two Er:CeF3 crystals doped with 1.0 and 1.2 wt.% Er203 and one pure CeF3 crystal weregrown, their absorption and A uorescence spectra at room temperature were measured. Compared with pure crystai,the emission intensity o f Ce3+ in Er : CeF3 decreased obviously, it is the sign of energy transfer from 5d state of lattice Ce3+ to 4f state o f Er3+ ions which improves the stimulation emission efficiency o f Er3+ ions.