Er^3+,Cr^3+共掺杂BaAl2Si2O8荧光粉的发光性质及能量传递

利用高温固相法合成BaAl2Si2O8:Cr^3+,Er^3+系列荧光粉,研究了Cr^3+和Er^3+掺杂对BaAl2Si2O8材料发光特性的影响.BaAl2Si2O8:Er^3+荧光样品在393 nm激发波长下只呈现出峰值为550 nm的绿色荧光,来源于2H11/2→4I15/2和4S3/2→4I15/2跃迁的叠加.BaAl2Si2O8:Cr^3+荧光样品在550 nm激发波长下呈现峰值为694 nm的红色荧光,来源于2E→4A2的跃迁.在共掺杂样品BaAl2Si2O8:Cr^3+,Er^3+中,用Cr^3+激发峰的凹槽处380 nm作为激发光,得到的发射峰不仅有Er^3+的发射峰位,还有Cr^3+的发射峰位,说明两个离子之间可能存在辐射能量传递;对共掺杂BaAl2Si2O8:1%Cr^3+,x%Er^3+样品的荧光光谱进行测试,随着x的增加,Cr^3+的激发和发射光谱强度均有所增加,并且当x=0.5时,光谱强度是原来的4倍.另外,当固定Cr^3+的浓度时,随着Er^3+的浓度增加,Cr^3+的荧光寿命逐渐增加;当固定Er^3+的浓度时,随着Cr^3+的浓度增加,Er^3+的荧光寿命逐渐减小.这些现象表明了Er^3+和Cr^3+之间存在共振能量传递,通过理论计算得到Er^3+和Cr^3+之间的能量临界距离为4.5 nm,属于电偶极-电偶极相互作用.

Luminescent Properties and Energy Transfer of Er3+ , Cr3+ Co-doped BaAl2Si2O8 Phosphors

BaAl2Si2O8:Cr^3+,Er^3+series phosphors were synthesized by high-temperature solid-phase method.The effects of Cr^3+and Er^3+doping on the light-emitting properties of BaAl2Si2O8 materials were studied.The BaAl2Si2O8:Er^3+fluorescence sample exhibited only green fluorescence with a peak value of 550 nm at an excitation wavelength of 393 nm,which is derived from the superposition of 2H11/2→4I15/2 and 4 S3/2 →4 I15/2 transitions.The BaAl2Si2O8:Cr^3+fluorescence sample exhibits red fluorescence with a peak value of 694 nm at an excitation wavelength of 550 nm,which is derived from the 2 E→4 A2 transition.In the co-doped samples BaAl2Si2O8:Cr^3+,Er^3+,380 nm is used as the excitation light at the groove of the Cr^3+excitation peak,and the obtained emission peaks include not only the emission peak position of Er^3+,but also the emission peak position of Cr^3+,which indicates that there may be radiant energy transfer between them;the fluorescence spectra of the co-doped BaAl2Si2O8:1%Cr^3+,x% Er^3+samples were tested.With the increase of x,the intensity of the excitation and emission spectra of Cr^3+increased,and when x=0.5,the spectral intensity is 4 times the original.In addition,when the concentration of Cr^3+is fixed,the fluorescence lifetime of Cr^3+gradually increases as the concentration of Er^3+increases;when the concentration of Er^3+is fixed,the fluorescence lifetime of Er^3+decreases gradually as the concentration of Cr^3+increases.These phenomena indicate the existence of resonance energy transfer between Er^3+and Cr^3+.The critical energy distance between Er^3+and Cr^3+is4.5 nm,which is an electric dipole-dipole(d-d)interaction.