Influence of the Structural Properties of Phosphors on the Color Rendering Index of a White LED

Purpose of research. Determine the content and forms of components of luminescent substances with the structure of garnet and nitride on the emissive properties of white LEDs.

Methods. Electron microscopic studies were carried out in conjunction with energy dispersive and X-ray phase analyzes of powder samples, produced by LLC "Monocrystal Paste". Lighting parameters were determined using a confocal Raman and fluorescence spectrometer OmegaScope with blue laser radiation.

Results. The correlation effect of physical and mechanical characteristics on the fluorescence spectra of powder materials with the garnet and nitride structure is built, their analysis and promising approaches to improving the structure of white LEDs and the color rendering index are carried out. The theoretical calculation of the content of the red component has been carried out.

Conclusion. Offering promising characteristics such as small size, safety, long life and luminous efficiency, white LED lamps perform in a high CRI alternative to natural light, which characterizes the contrast in which objects are displayed by irradiated light. The main purpose of the LED source is to convert the blue light of an InGaN semiconductor crystal into white light over a wide frequency range. As a result of the research, the direct influence of the composition and structure of photoluminescent substances on the emissive properties of the LED has been established. Thus, by including gallium in yttrium-aluminum garnet, the wavelength of the fluorescence maximum decreases from 547 nm to 523 nm. When strontium is replaced in the nitride phosphor with calcium, the shape changes towards red, namely from 600 nm to 650 nm. With a multicomponent phosphor, including both phosphors, the LED source crosses the entire frequency range of visible radiation.

1. He G., Xu J., Yan H. Spectral optimization of warm-white light-emitting diode lamp with both color rendering index (CRI) et special CRI of R9 above 90. AIP advances, 2011. vol. 3, no. 1, pp. 032160. https://doi.org/10.1063/1.3644342.

2. Konnova S. I. Sol-Gel synthesis et investigation of Un-doped et Eu-doped strontium aluminate Sr3Al2O6. Perspektivy razvitiya fundamental'nykh nauk. Sbornik nauchnykh trudov XV Mezhdunarodnoi konferentsii studentov, aspirantov i molodykh uchenykh [Prospects for the development of fundamental sciences. Collection of scientific papers of the XV International Conference of Students, graduate students et young scientists]. Tomsk, Tomsk St. Univ. Publ., 2018, vol. 2, рр. 147–149.

3. Shama M. S., Kichuk S. N., Kostyukov S. V., eds. Vliyaniye razlichnykh plavney na svetotekhnicheskiye parametry YAG:Ce [Influence of various fluids on the lighting parameters of YAG:Ce]. Novye ogneupory = New refractories, 2016, vol. 1 (8), рр. 50–53.

4. Davydova O. V., Drobyshevskaya N. E., Poddenezhny E. N., eds. Sintez nanostrukturirovannykh poroshkov ittriy-alyuminiyevogo granata, aktivirovannogo ionami tseriya i ikh primeneniye dlya formirovaniya napolnennykh polimernykh opticheskikh kompozitov [Synthesis of nanostructured powders of yttrium-aluminum garnet, activated by cerium ions et their use for the formation of filled polymer optical composites]. Himiya, fizika I tekhnologiya poverchosti = Chemistry, Physics and Surface Technology, 2017, vol. 8, no. 3, рр. 289–298.

5. Xia Z., Meijerink A. Ce3+-doped garnet phosphors: composition modification, luminescence properties et applications. Chemical Society Reviews. 2017, vol. 46, is. 1, рр. 275– 299. https://doi.org/10.1039/C6CS00551A.

6. Mares J., Beitlerova A., Nikl M., eds. Scintillation et optical properties of YAG:Ce films grown by liquid phase epitaxy. Radiation measurements. 2007, vol. 42, is. 4-5, рр. 533–536. https://doi.org/10.1016/j.radmeas.2007.01.047.

7. Shen C., Chu J., Qian F. High color rendering index white LED based on nanoYAG:Ce3+ phosphor hybrid with CdSe/CdS/ZnS core/shell/shell quantum dots. Journal of Modern Optics, 2012, Vol. 59, is. (14), рр. 1199–12.3. https://doi.org/10.1080/09500340.2012.693632.

8. Hua H., Feng S., Ouyang Z., eds. YAGG:Ce transparent ceramics with high luminous efficiency for solid-state lighting application. Journal of Advanced Ceramics, 2019, vol. 8, is. 3, рр. 389–398. https://doi.org/10.1007/s40145-019-0321-9.

9. Mihóková E., Babin V., Bartosiewicz K., eds Low temperature delayed recombination decay in scintillating garnets. Optical Materials, 2015, vol. 40, рр. 127–131. https://doi.org/10.1016/j.optmat.2014.12.011.

10. Samoylenko S. A., Tretyak E. V., Shevchenko G. P., eds. Crystal structure et optical properties of Lu3Al5O12:Ce3+ obtained by a colloidal chemical synthesis method. Journal of Applied Spectroscopy, 2015, vol. 81, is. 6, рр.1048–1055. Кузьменко А. П., Аникин Д. П., Родионов В. В.

11. Cordoncillo E., Julian-Lopez B., Martínez M., eds. New insights in the structure– luminescence relationship of Eu:SrAl2O4. Journal of Alloys and Compound, 2009, vol. 484, is. 1-2, рр. 693–697. https://doi.org/10.1016/j.jallcom.2009.05.018.

12. Divya A., Mathavan T., Asath R. M., eds. Assessment of strontium oxide functionalized graphene nanoflakes for enhanced photocatalytic activity: a density functional theory approach. AIP Conference Proceedings, 2016 no. 1731, is. 1, pp. 140024. https://doi.org/10.1063/1.4948190.

13. Watanabe H., Kijima N. Crystal structure and luminescence properties of SrxCa1− xAlSiN3:Eu2+ mixed nitride phosphors. Journal of Alloys and Compounds. 2009, vol. 475, is. 1-2, рр. 434–439. https://doi.org/10.1016/j.jallcom.2008.07.054.

14. Maruyama Y., Yanase Y., Watanabe T. Ammonothermal synthesis of chargecompensated SrAlSiN3:Ce3+ phosphor. Journal of the Ceramic Society of Japan, 2017, vol. 125, is. 5, рр. 399–401. https://doi.org/10.2109/jcersj2.16295.

15. Lee H., Liao J. D., Lee M. H., eds. Strontium oxide deposited onto a load-bearable et porous titanium matrix as dynamic et high-surface-contact-area catalysis for transesterification. Nanomaterials, 2018, vol. 8, is. 12, pp. 973. https://doi.org/10.3390/nano8120973.

16. Kang T., Lee S., Kim J., eds . Thermal durability of YAG:Ce ceramic with containing Al2O3 et its Raman analysis. Journal of Luminescence, 2020, vol. 222, pp. 117077. https://doi.org/10.1016/j.jlumin.2020.117077.

17. Lasch P., Hermelink A., Naumann D. Correction of axial chromatic aberrations in confocal Raman microspectroscopic measurements of a single microbial sporе. Analyst, 2009, vol. 134, is. 6, рр. 1162–1170. https://doi.org/10.1039/B822553B.

18. Hasegawa S., Hasegawa T., Kim S. W., eds Single crystal growth et crystal structure analysis of novel orange-red emission pure nitride CaAl2Si4N8:Eu2+ phosphor. ACS omega, 2019, vol. 4, is. 6, рр. 9939–9945. https://doi.org/10.1021/acsomega.9b00606.

19. Watanabe H., Kijima N. Synthesis of Sr0.99Eu0.01AlSiN3 from intermetallic precursor. Journal of the Ceramic Society of Japan, 2009, vol. 117 (1361), рр. 115–119.

20. Yadav P. J., Joshi C. P., Moharil S. V. Two phosphor converted white LED with improved CRI. Journal of luminescence, 2013, vol. 136, is. 1-4, рр. 1–4. https://doi.org/10.1016/j.jlumin.2012.10.039.

21. Cheng G., Mazzeo M., D'Agostino S., eds. Pure white hybrid light-emitting device with color rendering index higher than 90. Optics letters, 2010, vol. 3, is. 5, рр. 616–618. https://doi.org/10.1364/OL.35.000616.