Controllable Optical Tuning of Sr2Ga2GeO7∶0.02Sm3+Based on Charge Compensation of Mg2+
To further improve the photoluminescence characteristics and white light application performance of red phosphor Sr2Ga2GeO7∶0.02Sm3+(SGGOS),the Mg2+was used as charge compensation ion to optically tune the sample.Then a series of red phosphors Sr2Ga2GeO7∶0.02Sm3+,xMg2+(0≤x≤0.12)were synthesized by high temperature solid phase method.The results show that Mg2+can be successfully introduced into the sample SGGOS and replace Ga3+.In addition,the grain size of the these samples are about 1～10 μm.The fluorescence test results show that Mg2+can enhance the charge transport efficiency of Sm3+,and then significantly enhance the fluorescence emission(PL)intensity of the sample.Moreover,when the doping amount of Mg2+is 0.08,the fluorescence emission intensity of Sr2Ga2GeO7∶0.02Sm3+,0.08Mg2+(SGGOSM)is relatively the highest.Compared with the reference sample SGGOS,phosphor SGGOSM exhibits a relatively larger optical band gap(Eg),color purity and an en-hanced thermal stability,which effectively improves its electroluminescence performance in its white light diodes(WLED)ap-plication.As a result,the WLED device with SGGOSM as red phosphor component possessed an expressive performance with a high color rendering index(Ra)reaching to 90.5 and a correlated color temperature(CCT),decreases to 3563 K.These results provide an important guide for developing efficient red emitting phosphor for WLED device with high Ra and low CCT.
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