高色纯度高热稳定性红色荧光粉Sr3La2Ge3O12:Sm^3+的合成及其性能

通过高温固相法合成了一系列Sr3La2-xGe3O12:xSm^3+(0≤x≤0.04)红色荧光粉,并对样品的形貌、元素组成、晶体结构、发光性能及热稳定性进行了探究。结果表明:样品Sr3La2Ge3O12:xSm^3+为较宽尺寸分布的颗粒,且结构中仅含有Sr、La、Ge、O、Sm等元素。样品Sr3La1.97Ge3O12:0.03Sm^3+的Rietveld结构精修图与实测XRD图完全吻合,具有六方晶系结构。漫反射测试结果显示基质Sr3La2Ge3O12的带宽为5.54 eV,属于宽带隙材料。在404 nm激发下,样品Sr3La2-xGe3O12:xSm^3+(0≤x≤0.04)的最大发射峰位于601nm处,属于Sm^3+的6H5/2→4L13/2能级跃迁。此外,样品Sr3La1.97Ge3O12:0.03Sm^3+的发光性能最佳,其CIE色坐标为(0.5321,0.4601),色纯度高达94.2%,在298-473 K范围内具有较好的热稳定性,测试温度达到423 K时发射强度仍为室温时的81.6%。

Synthesis and Luminescence Properties of Red Phosphor Sr3La2Ge3O12:Sm3+ with High Color Purity and Thermal Stability

A series of red emitting phosphors Sr3 La2-xGe3 O12:xSm^3+(0≤x≤0.04)were synthesized through a conventional high temperature solid state method,and the morphology,elemental composition,crystal structure,luminescence properties,and thermal stability were studied.The results showed that sample Sr3 La1.97Ge3 O12:0.03 Sm^3+had a broad crystal size distribution.The energy dispersive spectrum(EDS)analysis predicted that there were only Sr,La,Ge,0,Sm elements in Sr3 La1.97Ge3 O12:0.03 Sm^3+.The Rietveld refinement patterns of Sr3 La1.97Ge3 O12:0.03 Sm3+crystallized in a hexagonal unit cell fitted well with the observed XRD results.The host lattice Sr3 La2 Ge3 O12exhibited an energy band gap of 5.54 eV which belongs to the class of wide band gap materials.Moreover,samples Sr3 La2-xGe3 O12:xSm^3+(0≤x≤0.04)exhibited a maximum emission peak located at 601 nm ascribed to the6 H5/2→4 L13/2 energy level transitions of Sm3+when excited at 404 nm.Significantly,sample Sr3 La1.97Ge3 O12:0.03 Sm^3+not only possessed a relatively optimum photoluminescence properties with a Commission Internationale De I’eclairage(CIE)coordinates of(0.5321,0.4601)and a color purity up to 94.2%among these synthesized materials,but also exhibited splendid thermal stability with the photoluminescence intensity remained 81.6%of its initial value when the temperature was 423 K.