Strong enhancement of 420∼425nm optical wavelength of blue LED by using CaF2 scintillating crystals as a cap

2012 ◽  
Vol 1392 ◽  
Author(s):  
Suzuka Nishimura ◽  
Muneyuki Hirai ◽  
Hiroshi Nagayoshi ◽  
Kazutaka Terashima
Keyword(s):  
Visible Light ◽  
Blue Light ◽  
Emission Intensity ◽  
Light Emission ◽  
Uv Light ◽  
Blue Light Emission ◽  
Optical Window ◽  
Blue Led ◽  
Optical Wavelength ◽  
Light Emission Intensity

ABSTRACTIt has been found that the blue light emission of LED is remarkably enhanced by using optical window of CaF2 disk doped with Eu2O3. The CaF2 crystals doped with Eu2O3 strongly absorb UV light with 330~420nm optical wavelength as a cutting filter. Instead, CaF2 crystals emit 420~425nm wavelength visible light. As a result, the UV light shifts to a light of around 420nm wavelength, and the LED light emission intensity markedly increases. In our experiments, the UV components were absorbed, while, around 420nm emitting light has been strengthened by more than 30%. The FWHM value is improved by around 30%.

Blue Light Emission from Germanium Ultrafine Particles by the Gas Evaporation Technique

1994 ◽  
Vol 358 ◽  
Author(s):  
Shinji Nozaki ◽  
S. Sato ◽  
A. Denda ◽  
H. Ono ◽  
H. Morisaki
Keyword(s):  
Blue Light ◽  
Ultrafine Particles ◽  
Light Emission ◽  
Uv Light ◽  
Hydrogen Atmosphere ◽  
Pure Hydrogen ◽  
Blue Light Emission ◽  
Long Time ◽  
Evaporation Technique ◽  
Gas Evaporation Technique

ABSTRACTThe ultrafine particles with diameters in the order of 10 nm were deposited onto Si and SiO2 substrates by evaporation of Ge in a pure hydrogen atmosphere. Although the as-deposited Ge ultrafine particles do not show any detectable luminescence, they emit blue light after being exposed to the UV light for a long time. The blue light is strong enough to be seen with the naked eye even under a room light. The photooxidation, unique to the Ge ultrafine particles, has been identified as a major factor contributing to the blue light emission.

The critical role of the coordination sphere in the high-efficiency blue-light emission from aminopyrazine metal-organic polymers

2021 ◽  
Vol 186 ◽  
pp. 109025
Author(s):  
João Humberto Dias Campos ◽  
Meiry Edivirges Alvarenga ◽  
Maykon Alves Lemes ◽  
José Antônio do Nascimento Neto ◽  
Freddy Fernandes Guimarães ◽  
...  
Keyword(s):  
Blue Light ◽  
Coordination Sphere ◽  
High Efficiency ◽  
Light Emission ◽  
Critical Role ◽  
Organic Polymers ◽  
Blue Light Emission ◽  
Metal Organic

Enhanced blue-light emission on Cd0.9-xZn0.1CrxS(0 ≤ x ≤ 0.05) quantum dots

2019 ◽  
Vol 45 (3) ◽  
pp. 3833-3838 ◽  
Author(s):  
I. Devadoss ◽  
P. Sakthivel ◽  
S. Muthukumaran ◽  
N. Sudhakar
Keyword(s):  
Quantum Dots ◽  
Blue Light ◽  
Light Emission ◽  
Blue Light Emission

LUMINESCENCE BEHAVIOR AND MECHANISM OF LIGHT-EMITTING POROUS SILICON

1994 ◽  
Vol 08 (02) ◽  
pp. 69-92 ◽  
Author(s):  
XUN WANG
Keyword(s):  
Porous Silicon ◽  
Blue Light ◽  
Light Emission ◽  
Energy State ◽  
Surface Recombination Velocity ◽  
Luminescence Spectroscopy ◽  
Carrier Injection ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Si Nanostructures

In this review article, we give a new insight into the luminescence mechanism of porous silicon. First, we observed a “pinning” characteristic of photoluminescent peaks for as-etched porous silicon samples. It was explained as resulting from the discontinuous variation of the size of Si nanostructures, i.e. the size quantization. A tight-binding calculation of the energy band gap widening versus the dimension of nanoscale Si based on the closed-shell Si cluster model agrees well with the experimental observations. Second, the blue-light emission from porous silicon was achieved by using boiling water treatment. By investigating the luminescence micrographic images and the decaying behaviors of PL spectra, it has been shown that the blue-light emission is believed to be originated from the porous silicon skeleton rather than the surface contaminations. The conditions for achieving blue light need proper size of Si nanostructures, low-surface recombination velocity, and mechanically strong skeleton. The fulfillment of these conditions simultaneously is possible but rather critical. Third, the exciton dynamics in light-emitting porous silicon is studied by using the temperature-dependent and picosecond time-resolved luminescence spectroscopy. A direct evidence of the existence of confined excitons induced by the quantum size effect has been revealed. Two excitation states are found to be responsible for the visible light emission, i.e. a higher lying energy state corresponding to the confined excitons in Si nanostructures and a lower lying state related with surfaces of Si wires or dots. A picture of the carrier transfer between the quantum confined state and the surface localized state has been proposed. Finally, we investigated the transient electroluminescence behaviors of Au/porous silicon/Si/Al structure and found it is very similar to that of an ordinary p-n junction light-emitting diode. The mechanism of electroluminescence is explained as the carrier injection through the Au/porous silicon Schotky barrier and the porous silicon/p-Si heterojunction into the corrugated Si wires, where the radiative recombination of carriers occurs.

scholarly journals The fabrication of nc-Si/SiO2 multilayers and blue-light emission

2003 ◽  
Vol 52 (4) ◽  
pp. 989
Author(s):  
Sui Yan-Ping ◽  
Ma Zhong-Yuan ◽  
Chen Kun-Ji ◽  
Li Wei ◽  
Xu Jun ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emission ◽  
Blue Light Emission

scholarly journals Red, White and Blue Light Emission from Europium Doped Al2O3 Confined into a Silica Matrix

2018 ◽  
Vol 08 (08) ◽  
pp. 338-345 ◽  
Author(s):  
Joan Reyes ◽  
Dulce Y. Medina ◽  
Miriam Aguilar ◽  
Miguel A. Barron ◽  
Elizabeth Garfias ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emission ◽  
Silica Matrix ◽  
Blue Light Emission
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