Papers by Keyword: Light Conversion

Abstract: White light-emitting diode (LED) is used in a new generation of solid-state lighting due to its advantages in energy saving and environmental friendliness. Based on this assumption, Emphasis was put on trying to establish a laboratory technique to convert UV-blue light into white light by using polymeric materials. In this work, an laboratory technique to convert UV-blue light into white light by using polymeric materials, consisting of red (R), green (G) and blue (B) for a white light generation. The project employed the use Colouring polymorph plastic as an active materials mixed with Silicone Sealant in different ratio and pumping by UV-Blue light. Colour rendering index (CRI) and correlated colour temperature (CCT) as main measurement parameters to evaluate the performance of the white light. The best white light appearance an indicated by photo and colour meter were achieved by mixing red (R), 0.05gm and green (G), 0.1gm the optimum results were CCT =3606k, CRI =70.3, x=0.3661, y=0.2925, and by mixing red (R), 0.005gm and green (G), 0.005gm the results were CCT=4891 k, CRI =63.8 and x=0.3359, y=0.2405.

Abstract: Homoepitaxial layers of fluorescent 4H-SiC were grown on 4 degree off-axis substrates by sublimation epitaxy. Luminescence in the green spectral range was obtained by co-doping with nitrogen and boron utilizing donor-acceptor pair luminescence. This concept opens possibilities to explore green light emitting diodes using a new materials platform.

Abstract: A unique method, so called, hydro-thermal synthetic method was applied to produce nano-sized inorganic blue (Y2SiO5:Ce) and red (Y2O2S:Eu+3) emitting phosphors. Electron microscopy revealed that the nano-sized emitting phosphor particles have spherical shape with 23-50nm in size. The particles can effectively change ultraviolet rays of 1-390 nm to infrared rays of 750nm -1mm, which are suitable to promote the growth of plants. The principle excitation and emitting spectrum of the red phosphor in 590-700 nm emitting spectrum were in the region of 308nm and 617nm, respectively, whereas, those of the blue phosphor in 420-470nm emitting spectrum were in the region of 254nm and 464nm, respectively. The addition of 0.1-0.2 wt% of the 2:1 mixed red and blue powders to a film showed the maximum emitting intensity of 537x1000 count/sec.

Abstract: In this article, Sm(Sal)xPhen, SmyY1-y(Sal)3Phen were synthesized and its films were prepared. They were characterized by infrared spectra (IR), ultra-violet visible spectrometer (UV), X-ray diffraction (XRD) and fluorescence spectroscopy. Sm/Y complexes and its mixture doped with the polyvinyl alcohol (PVA) showed photoluminescence at the wavelength of 646 nm. There was an excellent compatibility among Sm/Y complexes, the polyvinyl alcohol (PVA) and dimethyl sulphoxide (DMSO), which were used to prepare the resin film. The results indicated that Sm/Y rare earth light conversion films were better light conversion films with good compatibility in resins, and with emission wavelength suitable for plants’ photosynthesis.