Effect of phosphor sedimentation on photochromic properties of a warm white light-emitting diode

Abstract

In the process of producing a white light emitting diode, the consistency of the optical coherence and stability of the photochromic properties is a crucial index for measuring the quality of the product. Phosphor sedimentation is a significant factor affecting optical coherence, thus, in this paper, seven sets of control experiments were set up with the phenomenon of the phosphor precipitation at time intervals 0, 2, 5, 10, 20, 30, and 40 min. The color coordination concentration and optical properties were also tested. The results indicate that phosphor sedimentation occurs between 0 and 20 min, during which the color coordinate placement is concentrated, the central coordinates are (x = 0.4432 ± 0.004, y = 0.4052 ± 0.002); the quality was verified because the supply demand chain management (SDCM) was no greater than 7. Later, between 30 and 40 min, the central coordinates are (x = 0.4366 ± 0.003, y = 0.4012 ± 0.003), which had an SDCM value higher than 7, and had a more discrete color placement; it does not meet the requirements of the national standard GBT24823-2016 general lighting LED module performance.

SiO2@LaOF:Eu3+ in white light emitting diodes optic efficiency enhancement

“…Rare-earth fluorides have been exceptionally steady substrates for the doping of multiple optically engaged Eu 3+ particles. These elements have a strong refractive indicator, a weak phonon power, a great ionicity, a high resistance, and an atomic conductivity, leading to the reduced non-radiational degradation and grater illumination quantum performance [11], [12]. Surface modification has been discovered to be among the approaches with the highest proficiency for reducing surface imperfections and non-radiative channels by changing the spacing between radiant and quenching centers.…”

Surface coated red phosphors with silica nanoparticles and silica nanocomposites: performance modifications

“…The white LEDs utilizing phosphor integration and conversion are especially getting popular as they have several advantages over traditional lighting sources, for example, halogen and incandescent illuminations. These advantages include dependability, saving energy, cheaper maintenance, and enhanced safety [1]- [3]. As for normal white LEDs, a gallium nitride (GaN) blue LED chip packed with a yellow-emitting phosphor material, popular Y3Al5O12:Ce (YAG), would be commonly utilized.…”

Quantum Dots Electrostatically Adsorbed on the Surface of SiO2 Nanoparticle-Decorated Phosphor Particles for White Light-Emitting Diodes with a Stable Optical Performance

“…Many researchers have studied the effects of changeable distribution of phosphor in silicone on the spectra and optical parameters of phosphor-converted WLEDs. , Avoiding phosphor sinking is a direct way to maintain the stable distribution of phosphor. Researchers have provided some methods to evenly distribute phosphor in silicone of WLEDs, such as the modified phosphor with vinylsilane coupling agent, phosphor/silicone particles, and phosphor/glass. , However, these methods are unsuitable for the phosphor and QDs-added WLEDs for the following reasons: the high manufacturing temperature of phosphor/glass will thermally quench the QDs, and the phosphor/silicone and modified phosphor just slow down the sinking of phosphor instead of avoiding.…”

“…13−15 Many researchers have studied the effects of changeable distribution of phosphor in silicone on the spectra and optical parameters of phosphor-converted WLEDs. 16,17 Avoiding phosphor sinking is a direct way to maintain the stable distribution of phosphor. Researchers have provided some methods to evenly distribute phosphor in silicone of WLEDs, such as the modified phosphor with vinylsilane coupling agent, 18 phosphor/silicone particles, 19 and phosphor/glass.…”