efficient blue-emitting phosphor srlu 2 o 4 :ce 3+ with high thermal stability for near ultraviolet (~400u2009nm) led-chip based white leds

by:Getian     2020-08-09
Blue-
For near ultraviolet rays (NUV)based tri-
Color RGB fluorescent mixed color conversion white light emitting diode (LEDs)
It has been extensively investigated in the past few years.
In the NUV chip, the LED chip reaches the peak near 400nm, which is currently the most efficient.
However, most blue fluorescent bodies show inefficient excitation around 400nm.
Here, a new blue fluorescent body srlu2o: b3 with good matching with near 400nm chip and high thermal stability was developed.
The luminous spectrum shows a wide emission band at the peak of 460nm with a bandwidth of nearly 90 nm.
By optimizing the concentration of ce 3, the internal quantum efficiency (IQE)
Reached 76%.
Also, 86% of the room-
The temperature emission strength is still maintained at °c, indicating good thermal stability and practicality.
Based on the 405 nm chip, a series of white LEDs were prepared, which were coated with a mixture of new blue fluorescent substances and commercial yellow and red fluorescent substances.
High color rendering index (≥90)
When the relevant color temperature is adjustable in the range of 3094 to 8990 k, it is realized.
These results show that srlu2o: b3 can be used as blue-
Emitting fluorescent substances in NUV-based White led.
White LEDs have been widely deployed on solid
National lighting due to its superior efficiency and service life.
So far, the most common way to get white light based on monochrome LED is to turn yellow-
Fluorescent powder and other substitution of CE, y, aluminum, Garnet (YAlO: Ce)with a blue (InGa)N LED chip.
However, inconsistency in the aging properties of the blue chip and the fluorescent body may lead to instability of white light, which is blue light emitted by the chip and from the fluorescent body.
In addition, this type of white LED emits very little red light, so the color presentation index is very low.
In order to solve this problem, one can use another method to obtain stable white light through the combination of red-lightgreen-blue (RGB)
With near UV (NUV)LED chip.
In this method, the visible components of white light are produced only by fluorescent matter, showing a lower color point change compared to the forward directionbias currents.
In NUV chips, chips close to 400 nm are more attractive due to the highest energy conversion efficiency.
Therefore, this method requires that all three RGB luminous materials have effective excitation at about 400nm to maximize the efficiency of the device. Some blue-
Candidate for luminous fluorescent powder NUV (~ 400u2009nm)
Such as LiCaPO: Eu, BaLaNa (PO)
F: European Union, BaHfSiO: European Union, calussczrgeo: Ce, CaHfSiAlO: Ce, cadzsigao: Ce, CaLaGaSO: Ce, CaBOBr: EU, with NaSc )(PO): xEu .
However, few people can match well with chips close to 400nm, with high thermal stability at the same time.
So develop new blue-
The luminous materials have excellent thermal stability and high quantum efficiency. The rare-
SrLnO (Rare Earth cobalt oxide)
Lngd = gd, Ho, Er, Tm, Yb)
Because of their magnetic properties, the space group has been studied in depth.
Select SrLnO as host, Eu-
The doping SrLuO and SrGdO luminous materials were studied and they were considered as promising red luminous materials in solid-state light emitting devices.
Eu-doped SrLuO has a wide red emission centered at 610 nm, but it can be applied to optical temperature sensors instead of white LED due to its strong heat quenching.
In this paper, we report for the first time a new blue fluorescent body of SrLuO: Ce prepared by solid state reaction.
Light emission (PL)
The properties and temperature dependence of this novel fluorescent agent were investigated.
The new fluorescent body shows efficient blue emission, and the luminous excitation band matches well with the near 400nm NUV chip.
In addition, the phosphorus also has high thermal stability when 86% of the room temperature emission strength is kept at 150 °c.
White LEDs with high color rendering index (CRI)
At different relevant color temperatures (CCT)
Manufactured based on the NUV chip, the chip is coated with a mixture of a new blue fluorescent body and a commercial yellow and red fluorescent body.
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