This technology presents a method of producing an enhanced red phosphor powder consisting of a mixture of standard red phosphors and nano-silicon particles. By mixing the resulting enhanced phosphor with blue and green phosphors and passing through radiation from a purple/blue LED chip, white light will be produced. This approach will allow the achievement of a high level of colour rendering index (CRI) in the colour temperature range (CCT) of 2600-6700 K. In dry form, the powder is a highly efficient fluorescent material that can be used in the manufacture of LED lamps.
TECHNOLOGY FEATURES & SPECIFICATIONS
Using this method, the researchers created a silicon shell made of phosphor nanoparticles. Silicon dioxide powder (SiO2) or a medium-diameter semiconductor powder (~50-200 nm) is used as the carrier of silicon nanoparticles. Semiconductor powder includes doped metals ZnO (zinc oxide), ZnS (zinc sulfide), or Y2O2S (yttrium oxide sulfide). The synthesis of silicon nanoparticles occurs in an isopropyl alcohol medium. The slow evaporation of isopropyl alcohol creates a core-shell architecture.
A distinctive feature of this method is that the synthesis does not require expensive and particularly dangerous chemical precursors. The chemicals used in the synthesis are readily available on the market, some can be found in a regular pharmacy. This synthesis technology eliminates the formation of illiquids, i.e. there is no waste in the synthesis process and chemicals are used repeatedly in the process. Thus, the harmful impact on the environment is minimal.
The enhanced red phosphor powder based on silicon will be suitable as an additive to the phosphor mixture, in the manufacture of LEDs for lighting equipment.