| nanocrystallites have stimulated great interest in the research community because of their useful mechanical, thermal and electrical properties. Borates have been widely used as materials for second harmonic generation or host materials for fluorescence. In recent years, considerable efforts have been focused on the synthesis of borate materials nanoparticles and the exploration of their novel luminescence properties. However, there is little work on luminescence studies related to borate samples doped with transition metallic ions. The study of preparation and luminescence properties of borate nanocrystallites has important science and practice meaning. For exploring the relationship of the composition, structure and properties, we have focused on Zn3(BO3)2, β-BaB2O4 and BiB3O6 nanocrystallites doped with metallic ions according to the recent research result. Here, it mainly contains four parts as follows.Zn3(BO3)2, β—BaB2O4 and BiB3O6 nanoparticles have been prepared by co — precipitation method and Sol-gel method, respectively. Structural properties were investigated by XRD. TEM images were taken with transmission electron microscope. We report the photoluminescence characteristics of Zn3(BO3)2, β-BaB2O4 and BiB3O6 nanoparticles for the first time. In addition, the PL mechanism was discussed.Our observations are significantly different from that of references. These results are very useful for discussing luminescent mechanism of Zn3(BO3)2, β— BaB2O4 和 BiB3O6 nanoparticles and the interaction of hosts with different metal ions.The emission characteristics of Zn3(BO3)2 nanoparticles doped with Mn2+ and Ni2+ ions have been studied for the first time. Also,we discussed their luminescent mechanism. In Mn2* doped Zn3(B03)2 nanoparticles, as the similar ion radius between Mn2t ion and Zn2+ ion, the Zn2+ site of the host lattice maked it reasonable to assume that Mn2+ ions substituted for Zn2+ ions and formed new luminescence center. Strong orange luminescence (589nm) according to the transition 4Ti -* 6Ai of Mn2t has been observed from Mn2t-doped Zn3(B0s)2 nanoparticles. Because of the same reason, strong luminescence (613nm), which was assigned to the 'T2('D) - 3T2(3F) transitions of Ni2* ion, was observed.In conclusion, the emission mechanism of doped Zns(B03)2 nanoparticles is different from that of their bulk materials. Novel emission phenomena can be observed from doped Zn3(B0j)2 nanoparticles compared with their bulk materials. The new explanation for the luminescence mechanism of doped Zn?(B03)2 nanoparticles have been provided in this paper.Zn3(B03)2 nanocrystallites co-doped with two rare earth ions or one other metal ion and one rare earth ion, have been obtained by co-precipitation, respectively. Their emission properties have been researched for the first time. The results indicate that the new luminescence center of two metallic ions was formed in the co-doped Zn3(BO3)2 nanocrystallites. Due to the band gap of co-doped sample is different from that of undoped or single doped Zn3(B03)2 nanoparticles, The excitation and emission spectra of the co-doped Zn3(B03)2 nanoparticles vary with different co-doped ions. Also, the location energy level formed by co-doped ions varies with different co-doped ion pair. The novel emission phenomena have been observed from the co-doped Zn3(B03)2 nanoparticles. Also, he luminescence mechanism of the co-doped Zn3(B03)2 nanoparticles has been discussed.In Al3+ and Ce3+ co-doped Zn3(B03)2 nanoparticles. The effect ofAl3+ on luminescence properties of Ce3+ was studied. The results show that no obvious effect of Al3+ on the emission peak position of Ce3", but the emission intensity of Ce3+ doped A13t increased obviously for all samples. The emission intensity of 5% Al3+- 95% Zn3(B03)2 nanoparties was 5 times larger than that of 100% Zn3(B03)2:Ce3+ nanoparties. We concluded that the relation between the energy levels of Ce3' and the energy levels of Al3t may be appropriate for the energy transfer, the function of Al3t was to absorb efficiently energy and to transfer fully to Ce3+.Zn3(B03)2 nanoparticles co-doped with Eu3+ and Dy3+ ions were obtained by co-precipitation methods. PL experiments show red emitting from these co-doped Zn3(B03)2 nanocrystals at room temperature. In the Eu3" and Dy3r co-activated samples, duo to the energy transfer process from Eu3t to Dy3t, the emission intensity of Dy3+ ions is strongly enhancedWhen Ce3+ was doped singly, the emission band of Ce3+ at 405nmresulted in the 5d - 4Fj 0.7/2,5/2) transition. There were three emission) peaks with wavelength of 418rim, 544nm and 593nm in the emissionspectrum of Zn3(B03)2: Tb3+. When Ce3+ and Tb3" were co-doped, the emission band of Ce3" even could hardly be observed and the luminescence intensity of Tb3" was increased much than that Tb-doped sample. The experimental results indicated that there exists an effective energy transfer from Ce3+ to Tb3" in Zn3(B03)2 host. The experimental results indicated that electrical multipolar interaction between Ce3" and Tb3+ is the predominant mechanism for the energy transfer.In Zn3(B03)2:Eu nanoparticles, the fluorescence spectrum of Eu3* was investigated. The fluorescence spectrum showed that the optimum excitation wavelength was 395nm. At room temperature, emissionspectrum excited by 395nm showed four characteristic emission peaks.When different concentration of Mn2t were doped in the preparation of phosphors Zn3(B03)2: Eu3+, The emission intensity would be greatly enhanced. It is likely that the abnormal change of crystal checks that was led by the substitution of larger radius Eu3+ ion for smaller radius Zn2+ ion, the process of no radiation and crystal defect which lost energy were cut down. The improvement of Eu3+ ion crystal field condition gived rise to enhance of the main emission peak 615nm (to be attributed to 5D0-^rF2).There has not much work for the study of Zn3(B03)2 nanoparticles co-doped with two kinds of metallic ions. In this paper, we provided an efficient explanation for the luminescence mechanism of the co-doped Zn3(B03)2 nanoparticles. This is very important for improving the luminescence theories and discovering new luminescent materials.Eu3\ Dy3\ Cu2+ and Pb2+ ions doped in P —BaB2O* nanoparticles have been prepared using co-precipitation method. The novel emission phenomena were associated to the interaction of the metal ions and host.Pb2+doped and Cu2+, Pb2+ co-doped beta barium borate O - BaB204) nanoparticles have been prepared by co-precipitation method. The photoluminescence spectra of the doped samples have been investigated in detail. A relatively strong and stable visible-light emission band of Pb2+-doped ￡ - BaB204 sample centered at about 630 nm originating from the Pb2+-related charge-transfer transition was observed. Because of the sensitive action of Cu2t to Pb2+, the PL spectra of the co-doped sample are dramatically different from that of the Pb2+-doped sample and the luminescence intensities of the ￡ -BaB2(V. Pbz+ have been greatly enhanced.P - BaB2O4 nanoparticles co-doped with Eu3f and Dy3+ were synthesized and their luminescence properties have been studied. The emission of ￡ - BaB204: Eui+sample is composed of three main peaks at 595nm, 615nm and 660nm, which were assigned to 5D0-"TFj (J = i, 2, 3) of Eu3" ion. The 5D0-*7Fi electronic transition was the most prominent one in the spectrum. However, in the Eu3+ and Dy3* co-activated sample, the characteristic emission peaks of Dy3' ions were not observed and the luminescence intensity of 5D0-*7F2 transition was stronger than that of the 5D0-*7Fi transition . It was likely that some sites occupied by Eu3+ ions had deviated from centrosymmetry in ￡ - BaB204: Eu3+, Dy3+. Most of Eu3 ions were in the noncentral symmetric site, the parity selective rule would be partially released, resulting in a predominant electric dipole transition.BiB306 nanoparticles doped with Pb2+ have been synthesized by sol-gel method. The photoluminescence (PL) properties of BiB306: Pb2+ have been investigated in detail. Due to the strong interactions of the Pb2+ ion with the BiB306 may be expected. A relatively strong emission band centered at about 630nm originating from the Pb2+-related charge-transition in BiB306 nanoparticles was observed. The luminescence intensities varied with changing the concentration of Pb2" ion.The photoluminescence behavior of BiB306: Ce3+ and BiB306: Ce3\ Mn2+ nanoparticles was elucidated. Their emission properties have been systematically investigated at room temperature. The emission spectrum of BiB3O6: Ce3" consists of two sharp peaks at 370 and 405 run, which could be assigned to the 5d (2D) —- (2F7/2+2F6/2) (4fl) of Ce3* ions. Because of the energy transfer between Mn2* and Ce3+ ions, the emission spectrum of BiB3O6: Ce3+, Mn2t was dramatically different from that of BiB3O6: Ce3r sample. Also, the emission intensities of 370nmand 405nm changed BiB.iO6 with different molar ratios of Mn2+ in various proportions.
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