Green-emitting phosphors of yttrium borophoshate coactivated with Ce

3+

、Tb

3+

and Gd

3+

have been prepared for the first time by a single step of firing

using BPO4 and rare earth oxides as reactants.With the aid of emission spectra and excitation spectra

the spectroscopic properties of Ce

3+

、Tb

3+

and Gd

3+

and interaction among them in yttrium borophosphate have been studied.In the systems doped with Tb

3+

Ce

3+

or Gd

3+

the energy transfers from Ce

3+

to Tb

3+

or from Gd

3+

to Tb

3+

are observed

but in the system activated with Ce

3+

and Gd

3+

the competitive absorption and individual emission between them are found.After the incorporation of gadolinium into the yttrium borophosphate doped with Ce

3+

and Tb

3+

the increment of Ce

3+

emission intensity is more than that of Tb

3+

emission intensity. It is considered that the increment of Ce

3+

emission intensity is due to prevention of energy transfer from Ce

3+

to Tb

3+

and that of Tb

3+

emission intensity may attribute to effective energy transfer form Gd

3+

to Tb

3+

.In above system

Gd

3+

prevention of energy transfer from Ce

3+

to Tb

3+

may exists

which makes it impossible that Gd

3+

ion absorbs energy from Ce

3+

ion and transfer the energy to Tb

3+

ion

because 5d energy level of Ce

3+

ion is lower than 6I and 6P energy levles of Gd

3+

ion. If yttrium is replaced wholly by gadolinium in the matrix

the relative brightness of the prepared phosphor increases

however

x value of chromatic cordinates decreases slightly

so controlling the amount of gadolinium in the matrix will be of advantage to improving the luminescent characteristics of phosphors.