Doping Effect of Bi3+ on the Properties of YAG∶Ce3+,Mn2+ Phosphor Ceramics for Warm WLEDs

A series of Bi3+-doped YAG∶Ce3+,Mn2+ ceramics was synthesized successfully by gel-casting method and structurally characterized by XRD and SEM.The doping effect and related mechanism of Bi3+ upon the luminescent property were studied.It can be assigned to the energy transfer of multipolar interaction from Bi3+ to Ce3+,leading to the improvement of emission intensity about 58％ for 0.0001 Bi3+ and 0.05 Mn2+ doping.In addition,the emission is significantly red-shifted with the peak at 590 nm for the Y2.9939Ce0.006Bi0.0001Al4.96Mn0.02Si0.02O12 ceramic specimen with in-line transmittance 81.6％ at 1100 nm.The LED module assembled from Y2.9939Ce0.006Bi0.0001Al4.96Mn0.02Si0.02O12 ceramic owns correlated color temperature (CCT) of 3960 K and luminous efficiency (LE) of 92 lm/W,implying that doping Bi3+ shows a good sensitization effect in the YAG∶Ce3+,Mn2+ ceramic system and further serving as an attracting phosphor candidates for warm WLEDs applications.