We report results of the luminescence properties of the three garnet type phosphors Ce3+-doped Ca3Sc2Si3O12 (CSSO:Ce3+), Sr3Y2Ge3O12 (SYG:Ce3+) and Y3Al5O12 (YAG:Ce3+), investigated using optical spectroscopy techniques and vacuum referred binding energy (VRBE) diagram analysis.

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We study the photoluminescence properties of the red-emitting phosphor Ca 9 Eu(VO 4) 7 and establish a strong red emission centered at 613 nm under excitation at 395 nm (near ultra violet light, near-UV light) due to the intra-configurational 5 D 0 → 7 F 2 transition within the 4f 6 configuration of the Eu 3+ ions. The intensity of the emitted light decreases with increasing temperature and at T = 470 K about 50% of the intensity of the emitted light at room temperature is lost. Five different red-LED prototypes were constructed by applying a mixture of Ca 9 Eu(VO 4) 7 phosphor and silicone gel on the headers of near-UV LED chips. The prototypes showed a color output from violet for the lowest phosphor concentration (133 g phosphor /l silicone gel), reaching an almost pure red-light output for the highest phosphor concentration (670 g phosphor /l silicone gel). The luminous efficiency of optical radiation (LER) was found to decrease slightly with increasing applied current. For the highest phosphor concentration, the LER decreases from 238 lmW −1 for 1 mA current supply to 235 lmW −1 for 18 mA current supply. The external quantum efficiency decreased from 7.33% for the lowest phosphor containing LED prototype to 4.13% for the highest one.