In recent years

the borate-based phosphors have attracted great interest due its easy synthesis

low preparative temperature and high fluorescent yields. Many borates which contain BO₄ group have attracted more and more attention

because the tetrahedral structure of BO₄ can restrain the oxidation of divalent rare-earth ions. The typical representations of better borate matrix are SrB₆O₁₀

Sr₂B₅O₉<em>X(X</em>=Cl

Br) and SrB₄O₇. Strontium borate phosphors are usually synthesized by traditional solid state reactions by using SrCO₃ and H₃BO₃ as raw materials. However

less attention has been paid to the influence of synthesis route on the final performance of the products. In this work

SrB₄O₇[DK(]∶[DK)]Eu phosphors were prepared using hydrated strontium borates(SrB₂O₄·4H₂O and SrB₆O₁₀·5H₂O) as raw materials. The effect of doping concentration and post-calcining temperature on the luminescence properties was studied. It was found that Eu ions with two oxidation states (+2 and +3) coexist in the SrB₄O₇ host. The emission spectrum shows that the main emission peak located at 367 nm

which is attributed to Eu²⁺ ions transition from 4f⁶5d to 4f⁷(⁸S_7/2). The emission peaks of Eu³⁺ ions located at 588

600

614

651 and 700 nm corresponding to the transitions ⁵D₀→⁷F₀

⁵D₀→⁷F₁

⁵D₀→⁷F₂

⁵D₀→⁷F₃

⁵D₀→⁷F₄ respectively. Among them

the dominant emission is the electric-dipole transition ⁵D₀→⁷F₂

indicating that the Eu³⁺ ion occupies asymmetrical center in lattice. <br>The emitting intensity mainly depends on the amount of luminescence center which is relate to the doping concentration. The emitting intensity increases to a maximum with the increment of doping concentration

and then it decreases because of concentration quenching. When the Eu concentration is about 2%

the maximum of emitting intensity occurs. Post-calcining temperature influences on the chemical structure form of resultant powder. SrB₂O₄

SrB₆O₇ and SrB₄O₇ are formed when the post-calcining temperature is lower than 900 ℃. In these borates

SrB₂O₄ contains only triangular BO₃ groups

SrB₄O₇ contains only tetrahedral BO₄ groups

and SrB₆O₁₀ contains both the BO₃ and BO₄ groups. As the temperature elevates

the proportion of SrB₄O₇ increases and the single phase of SrB₄O₇ can be obtained at 900 ℃. As a fact that the BO₄ groups can stabilize the divalent rare-earth ions to avoid oxidation

so that more Eu³⁺ ions can be reduced to be Eu²⁺ ions and the emission intensity would increase. It was also found that the emission intensity from the sample synthesized using hydrated borates is higher than that from the sample synthesized by traditional route.