【摘要】 <正> 近年来人们对LaOBr:Tb的合成及其发光特性的研究日益增多。LaOBr:Tb不仅是良好的X光增感屏材料,也是较好的阴极射线发光材料。为了进一步提高它的亮度,降低了b的含量（因Tb很贵）,寻求LaOBr中Tb³⁺发光的敏化剂是很重要的。在Ce³⁺、Tb³⁺激活的许多材料中（如铝酸盐、磷酸盐、YAG等）都存在着Ce³⁺→更多还原

【Abstract】 The luminescence of LaOBr:Ce, LaOBr:Ce,Tb and LaOBr:Tb phosphors under UV and cathode ray excitation has been studied.The excitation spectra of Tb3 + ion in LaOBr:Tb consists of a strong broad 4f→5d transition band at 254nm and some weak 4f→4f transition lines in the wavelength range of 300-400nm. The excitation bands of LaOBr:Ce at 352.5, 314.5 and 289nm originate from transition between the 4f-ground state (7F) and the 5d-excited state (2D). The excitation spectrum of Tb3+ ion in LaOBr:Ce3 + , Tb3+ consists of four bands at 254, 289, 314.5 and 352.5nm due to Tb3 + and Ce3+ .It is clear that only the excitation bard at 254nm belong to Tb3+ ions and the other three bards are the excitation bands of Ce3+ ion.With increasing Ce3+ concentration the intensity of Tb3+ excitation band at 254nm decreases, at the same time the intensities of the Ce3+ excitation bands at 289, 314.5 and 352.5nm increase.The above results suggest that the excitation of Tb3+ in LaOBr:Ce3+, Tb3 + under UV-365mn excitation occurs mainly through the energy transfer of Ce3+→Tb3+ and there must be quenching process of Tb3+ emission due to Ce3 + when Tb3 + is directly excited with 254nm wavelength.The emission spectrum of LaOBr:Tb3 + consists of the 5D3→7F1 and 5D4→7FJ (J = 0,1,2.....6) transition. The main peaks in these two groups are 5D3→7F4 (436nm) and 5D4→7F5 (543nm) transitions, respectively.The emission of LaQBr:Ce3+ is a broad band with a maximum at 435nm. The intensity of Ce3+ emission increases with increasing Ce3+ concentration. But when Ce3+ concentration is between 0.03-0.1 the concentration self-quenching of Ce3+ emission occurs.In the emission spectrum of LaOBrrCe3+, Tb3+ there is not only Ce3+ emission band at 435nm, but also the 5D3→7FJ and 5D4→7FJ transitions of Tb3+.Under 365nm excitation, the main peaks (5D3→7F4 and 5D4→7F5) of Tb3+ transitions increase slowly with increasing Ce3+ concentration. When Ce3+ concentration get at 3×10-4, 5D3→7F4 transition arrives at maximum intensity, about 40-60 times the intensity of the sample without Ce3+ ion. Then the emission intensity of 6D3→7F4 transitions quickly decreases to zero, but the emission intensity’ of 5D4→7F5 transitions increases continuously. When Ce3+ concentration is 0.03 a steep rise of the 5D4→7F6 transitions suddenly occurs. At the time that Ce3+ concentration arrives at 0.05, the intensity get at the maximium, increasing more than 100 times in comparison with the sample without Ce3+ ion.These results show that under the 365nm excitation both 6D3→7FJ and 5D4→7FJ transitions were sensitized by Ce8+ concentration range and the sensitization of the 6D4→7FJ transition is more effective.For better understanding the quenching of Tb3+ luminescence by Ce3+ , we used Ar+ laser -4880A as the excitation source to selectively excite 5D4 level of Tb3+. It is found that 3D4→7F transition decreases with increasing Ce3+ concentration. This shows that besides sensitization effect, Ce3+ can also quench the emission of the Tb3+.Under cathode ray (10kV, 1μA/cm2) excitation, dominant effect of Ce3+ on Tb3+ luminescence in LaOBr:Ce, Tb is quenching. Only in the range of low concentration (1×10-5~1×10-4) there is enhancement 5D3 emission of Tb3+, so that total brightness is increased slightly. However, 6D4 emission of Tb3+ decreases with increasing Ce3+ concentration all the time.The temperature dependence of Ce3+ luminescence intensity in LaOBrs Tb, Ce is similar to that in LaOBrtCe. But the temperature of thermal quenching becomes smaller and the intensity is reduced and decreases with temperature more rapidly. The temperature range (-50~ + 100℃) in which the intensities of Ce3+ emission in LaOBr:Tb, Ce decrases is just that in which the Tb3+ emission is enhanced. This shows that energy transfer of Ce→Tb exists in LaOBnTb, Ce. According to that Ce→Tb transfer is more efficient at higher temperature. We conclude that the transfer process is phonon assisted.To sum up, in LaOBr:Ce3+, Tb3+, Ce3+ rot only can sensitize Tb3+ luminescence, but also can quench Tb3+ luminescence. It更多还原