Synthesis And Characterization Of Red Phosphors Base On Calcium Molybdate

White light-emitting diodes(LEDs), known as the fourth generation of lighting source, have gained wide attention due to their high efficiency, reliability, environment friendly, small volume, long service life and low energy consumption. Therefore, the research on phosphors is rapidly increasing and has become one hot subject. In this paper, we synthesized red phosphors which employed the tungsten molybdenum solid solution as host and Eu3+ as activation ion, and studied the effects of charge compensating agent, sensitizing agent on its luminescent properties. In addition, we synthesized Eu3+ or Sm3+ activated silicates phosphors and preliminary explored their luminescent properties.Ca1-xSrxMo1-yWyO4:Eu3+,Li+/Bi3+/Lu3+ red phosphors which employed Li+ as charge compensating agent or Bi3+/Lu3+ as sensitizing agent were synthesized by a sol-gel method. The phase compositions were characterized by X-ray diffraction(XRD) and Raman spectrum, which showed the single phase of tetragonal structure was formed. The samples showed a regular shape and the particle size grew rapidly with increasing calcining temperature according to the results of the scanning electron microscopy(SEM). The main excitation peak of Ca1-xSrxMo1-yWyO4:Eu3+,Li+/Bi3+/Lu3+ phosphors located at 395 nm, which showed that the phosphors could be excited by InGaN chip. The main emission peak was at 618 nm, which matched the requirement of red phosphors. The luminescent intensity changed greatly when doped Eu3+ activated ion and Li+ charge compensating agent or Bi3+/Lu3+ sensitizing agent with different concentration. Furthermore, at 150°C, the relative luminescent intensity of Eu3+,Bi3+ co-doped phosphors and Eu3+,Lu3+ co-doped phosphors decreased to 85% and 80% of that measured at 30°C, respectively, which suggested that these phosphors had good thermal stability.Sr1-xBaxMo1-yWyO4:Eu3+,Sm3+/La3+ red phosphors which employed Sm3+/La3+ as sensitizing agent were synthesized by a sol-gel method. The phase compositions were characterized by XRD and Raman spectrum, which showed the single phase of tetragonal structure was formed. The main excitation peak of Eu3+,Sm3+ co-doped and Eu3+,La3+ co-doped phosphors located at 404 nm and 395 nm, respectively, which showed that the phosphors could be excited by InGaN chip. The main emission peak located at 618 nm, which matched the requirement of red phosphors. The luminescent intensity changed greatly when doped Eu3+ activated ion and Sm3+/La3+ sensitizing agent with different concentration. Furthermore, at 150°C, the relative luminescent intensity of Eu3+,Sm3+ co-doped phosphors, Eu3+,La3+ co-doped phosphors and Eu3+ single doped phosphors decreased to 63%, 67% and 57% of that measured at 30°C, respectively, which suggested that these phosphors had good thermal stability.La4Mg2Ti3Si4O22:Eu/Sm and La4MgAl2Ti2Si4O22:Eu/Sm red phosphors which employed Eu3+ or Sm3+ as activated ion were synthesized by a sol-gel method and solid state method. The phase compositions were characterized by XRD and Raman spectrum, which showed the single phase of monoclinic structure were formed. The main excitation peak of Eu3+ doped and Sm3+ doped phosphors located at 395 nm and 404 nm, respectively. The main emission peak of them located at 618 nm and 605 nm, respectively. The luminescent intensity changed greatly when doped activated ion with different concentration. However, the ratio of the emission intensity at 568 nm and 650 nm with 605 nm of Sm3+ doped phosphors and the emission intensity at 592 nm with 618 nm of Eu3+ doped phosphors were large, which indicated that the phosphors couldn’t obtain pure red light when used the two kinds of materials as host.