Cr3+ ions improving the spectral properties of YAG: Ce3+ luminescent ceramics for white LD lighting

The lack of red light emission in Y3Al5O12:Ce3+ (YAG:Ce3+) luminescent ceramics has resulted in high color temperature and low color rendering index for solid state illumination, such as, LED or LD. Therefore, Y2.94Al5-xCrxO12:0.06Ce3+ (x = 0.004, 0.029, 0.054, 0.079, 0.104 mol) luminescent ceramics were prepared by vacuum sintering method. The doping of Cr3+ ions caused the weak red emission peaks between 675 nm and 720 nm, and the luminescence intensity of red light increased first and then decreased with the increase of Cr3+ ions doping content. The best doping concentration of Cr3+ ions is 0.054 mol. And in the co-doped system of ceramics, we confirmed the energy transfer from Ce3+ to Cr3+. YAG:Ce3+, Cr3+ series ceramics yielded a slight shift in color coordinates towards the red light area. Meanwhile, as the concentration of Cr3+ ions increasing, the color rendering index began to show an increasing trend with a maximum value of 79.4. The consequences display that Ce, Cr co-doped garnet luminescent ceramics are promising for red light supplementation and high CRI lighting applications of white LD.