Experimental Scheme on the synthesis of Sr2MgSi2O7:Eu2+,Dy3+ and SrAl2O4:Eu2+,Dy3+ by Sol-Gel Method

Experimental Scheme on the synthesis of Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺ and SrAl₂O₄:Eu²⁺,Dy³⁺ by Sol-Gel Method（Ⅰ）

In this section we mainly introduce the preparation method on the synthesis of Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺  and  SrAl₂O₄:Eu²⁺,Dy³⁺ and the related raw materials. And present the reaction equation. This is just the step 1,following step will be confirmed after discussion.

Part 1   Sr₂MgSi₂O₇:Eu²⁺,Dy³⁺

1. Prepare process

Analytical grade Mg(NO₃)₂6H₂O, Sr(NO₃)₂, Si(OC₂H₅)₄(TEOS) and guaranteed grade Eu₂O₃, Dy₂O₃ were used to synthesize precursor. A stoichiometric mixture of Eu₂O₃ (0.0176 g) and Dy₂O₃ (0.0373 g) were dissolved in nitric acid and then mixed with the DI water (18 ml), Mg(NO₃)₂6H₂O (2.564 g) and Sr(NO₃)₂ (4.169 g). TEOS (4.5 ml) and ethanol (5 ml) were added into above solution whose pH was adjusted to 2 by nitric acid. The above mixture was stirred until transparent sol completely transformed to transparent gel. Subsequently, transparent gel was put in room temperature for 24 h and then dried in vacuum drying oven at 110 C for another 24 h. The resulting opaque dry gel was then fired at 1300 C for 3 h in a graphite reducing atmosphere to obtain white LPL crystals. (The small H₃BO₃ (about 10mol% of one Silicate were added as a flux. The mixture was put into the smaller crucible. Then bigger crucible was employed covering outside of small one. Filling with activated charcoal in the interlayer between the both.)

2. Analysis method

XRD, Ultraviolet-visible spectra, Stokes Luminescence decay curves, UC emission spectra and decay curves, etc.

3. Reagents

4. Reaction equation

(Note: 1.according to Feng Ye et al, the sample in the above proportion has higher luminescence intensity

2. First prepare this sample only to investigate the effect in following process.)

5. Ingredient data in details showed in following table

                                                                     w/g

Part 2   SrAl₂O₄:Eu²⁺,Dy³⁺

1. Prepare process

Stoichiometric amounts of Sr(NO₃)₂, Al(NO3)₃9H2O, Eu₂O₃, and Dy₂O₃ were employed as the raw materials. A stoichiometric mixture of Eu₂O₃ (0.0176 g) and Dy₂O₃ (0.0373 g) were dissolved in nitric acid and then mixed with the DI water (18 ml), Al(NO3)₃ (2.564 g) and Sr(NO₃)₂ (4.169 g),glycerol ,citric acid and ethanol that were used as chelating agent were added into above solution whose pH was adjusted to 2 by nitric acid. The above mixture was stirred until transparent sol completely transformed to transparent gel. Subsequently, transparent gel was put in room temperature for 24 h and then dried in vacuum drying oven at 110 C for another 24 h. The resulting opaque dry gel was then fired at 1300 C for 3 h in a graphite reducing atmosphere to obtain white LPL crystals. (The small H₃BO₃ (about 10mol% of one Silicate were added as a flux. The mixture was put into the smaller crucible. Then bigger crucible was employed covering outside of small one. Filling with activated charcoal in the interlayer between the both.)

Analysis method

XRD, Ultraviolet-visible spectra, Stokes Luminescence decay curves, UC emission spectra and decay curves, etc.

2. Reagents

3. Reaction equation

(Note: 1.according to Lin et al, the sample in the above proportion has higher luminescence intensity

2. First prepare this sample only to investigate the effect in following process)

4. Ingredient data in details showed in following table

                                                                     w/g

Part 3   LiGa5O8:Cr³⁺

1. Prepare process

Stoichiometric amounts of LiNO₃, Ga(NO3)₃9H2O, Cr(NO3)₃9H2O were employed as the raw materials. A stoichiometric mixture of LiNO₃, Ga(NO3)₃9H2O, Cr(NO3)₃9H2O were dissolved in nitric acid and then mixed with the DI water, ,glycerol ,citric acid and ethanol that were used as chelating agent were added into above solution whose pH was adjusted to 2 by ammonia water. The molar ratio of citric acid to glycol was set at1:1.5. excess glycol was used to assure complete polymerization of citric acid with glycol. The molar ratio of citric acid to total metal ion was 4:1. The mixture solution was heated and stirred at 130℃ for 1h on a hot plate to remove water, followed by further heating up 300℃ to initiate polymerization. During this reaction, citric acid chelated with metal ions and reacted with glycol to form gels. After polymerization reaction, colored gels were formed. To remove the residuals, the gels were calcined at 900℃ in the air for 2h. the obtained powders were later heated in a reduced atmosphere with active C at 1250℃(The small H₃BO₃ (about 10mol% of one Silicate were added as a flux. The mixture was put into the smaller crucible. Then bigger crucible was employed covering outside of small one. Filling with activated charcoal in the interlayer between the both.)

Analysis method

XRD, Ultraviolet-visible spectra, Stokes Luminescence decay curves, UC emission spectra and decay curves, etc.

2. Reagents

3. Reaction equation

(Note: 1.according to Lin et al, the sample in the above proportion has higher luminescence intensity

2. First prepare this sample only to investigate the effect in following process)

4. Ingredient data in details showed in following table

                                                                     w/g