| Sunlight-Conversion Film (SCF) is one of the function films as a hot topic in recent years. Itcan convert UV or yellow-green light into blue or red light that are able to be used by plants.Therefore, it improves light quality that irradiated into green-house and the utilization ratio ofsunlight, helping the crops’ early-ripe. SCF used in agriculture can take full advantage of thecleaning and reproducible resource-sunlight. In that way, the utilization of chemical fertilizer andpesticide will be decreased, and we could enjoy green-food. The function of the light convertioncan be achieved by add the Sunlight-Conversion Agent (SCA) into SCF. However, most SCA arenot stability and expensive which restrict its’ application in SCF. In this paper, we are aimed toresearch stability and lowcost SCA.The staring materials consist of ZnO, Al(OH)3, GeO2, Cr(NO3)3·9H2O, H3BO3. The sampleswere prepared by a solid-state reaction method. The results show that both of the emissionintensity and persistence time of the ZnAl2-xGe0.75xO4: Cr3+samples increased when Ge4+ionsreplaced parts of Al3+ions in ZnAl2O4:Cr3+. The fluorescence spectra and diffuse reflectionspectra of the ZnAl2-xGe0.75xO4:1.0%Cr3+phosphor show that the emission spectra of thephosphor match with the photosynthesis of plants very well. The emission intensity increaseswith the Ge4+content, reaching a maximum at Ge4+content of x=0.7, and the decreases at higherGe4+content. The intensity of the emission peak of the ZnAl1.3Ge0.525O4:1.0%Cr3+phosphor isnearly2times stronger than that of the ZnAl2O4:Cr3+phosphor. The emission intensity increaseswith the rosting temperature and time increasing. And the optimized rosting temperature andtime is1300℃and2h, respectively.The staring materials consist of Al(OH)3, Cr(NO3)3·9H2O, H3BO3. The samples wereprepared by a solid-state reaction method. The results show that H3BO3plays a crucial role insynthesis and luminescence of the phosphor. The sample with initial addition Al/B=3.5gives thestrongest emission. The synthesis conditions suggest that efficient red emission of the phosphorcan be achieved at a calcining temperature1150℃for1h. Al18B4O33: Cr3+phosphor convertsthe yellow-orange into red. The reflectance spectra show that the samples have strong absorptionin both UV and yellow-orange region and have a promising prospect in the light conversion material for agricultural applications.The staring materials consist of MeNO3(Me=K, Na), Al(NO3)3·9H2O, Cr(NO3)3·9H2O,glycerinum, distilled water. The MeAl6O9.5:Cr3+(Me=K, Na) phosphors were prepared by acombustion method. The KAl6O9.5:Cr3+and NaAl6O9.5:Cr3+optimized sintered temperature is1100℃and950℃, respectively. With the calcination time increased, the emission intensity ofthe MeAl6O9.5:Cr3+(Me=K, Na) phosphors increases, and after a certain time the emissionintensity reaches at its maximum. The reflectance spectra show that the samples have strongabsorption in both UV and yellow-orange region. The MeAl6O9.5:Cr3+(Me=K, Na) phosphor canbe excited with yellow-orange light in the range of520~620nm and give intensitive emission inthe range of660~710nm. The maximum excitation wavelength of KAl6O9.5:Cr3+and NaAl6O9.5:Cr3+is589nm and580nm, respectively. The MeAl6O9.5:Cr3+(Me=K, Na) phosphors give thestrongest emission with initial addition glycerinum/metal ions (F/M) ratio is0.4. The effect ofNH4NO3on the photoluminescence intensity is investigated. |
