State Lighting Applications Research Articles

Pure orange color emitting Sm3+ doped BaNb2O6 phosphor for solid - state lighting applications

Single phase pure orange light emitting BaNb2O6:xSm3+ (0.5≤x≤3.0mol%) phosphors with orthorhombic structure have been synthesized via high temperature solid state reaction method. Crystal structure, morphology, luminescent and decay properties were studied extensively for the synthesized phosphor. The luminescence spectrum of Sm3+ doped BaNb2O6 phosphor exhibits three intense peaks centered at 565, 599 and 645nm corresponding to the 4G5/2→6H5/2, 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions, respectively. The optimum concentration for Sm3+ doped BaNb2O6 is observed as 1.5mol% and the probable energy transfer mechanisms between Sm3+ ions caused concentration quenching have been explained in detail. The calculated Commission Internationale de L’Eclairage (CIE) chromaticity coordinates have been found to be (0.557, 0.440) lies in the pure orange region, which is in the close proximity to the Nichia corporation developed amber LED. The luminescence decay lifetime for 4G5/2 excited level was found to be in the microseconds (µs) range. The Sm3+ doped BaNb2O6 phosphor could be a potential candidate for use in the display and solid - state lighting applications.

Synthesis and Luminescence Properties of Doped Magnesium Boro-Tellurite Ceramics

Glass has been widely utilized in the field of lighting, telecommunication and spectroscopy. Boro-tellurite is one of the suitable glasses used for solid state lighting and laser application. The investigation on the luminescence properties of rare earth doped ceramic is rarely used due to the opacity. In this paper boro-tellurite prepared in ceramic can show the better luminescence with the less advantage. The aim of this paper is to present the effect and advantages in luminescence results of boro-tellurite ceramics doped with the constant amount of rare earth. Doped magnesium boro-tellurite with Eu3+ and Dy3+ ceramic have been prepared using solid state reaction method with the compositions of xTeO2-(70-x)B2O3-30MgO with 10≤x≤40, and have been doped with Eu2O3 (1mol%) and Dy2O3 (1mol%) . The characterizations of the samples have been investigated by means of X-Ray diffraction, Raman, Infrared and Photoluminescence spectroscopy. From the X-ray diffraction results, two phases are assigned to MgTe2O5 and Mg2B2O5. Raman spectroscopy showed strong bands observed in the vicinity of 140, 175, 220, 266, 332, 403, 436, 646, 694, 723, 757 and 806 cm-1. FTIR spectra showed bands located in the range between 400-800 cm-1 are assigned to the bending mode of Te-O-Te, TeO3 and TeO4. In the range of 800-1400 cm-1,the bands are associated with B-O, B-O-B, BO3 and BO4 bonds. The emission transition 5D0-7F2 corresponded to the red emission (612 nm) was found to be the most intense in all the Eu3+-doped magnesium boro-tellurite ceramics.

32.4: Quantum Dot Light Emitting Diodes for Full‐color Active‐matrix Displays

AbstractQuantum dot light emitting diodes (QLEDs) are a printable thin film electroluminescent technology that delivers exceptional color and efficiency at low cost of manufacture for display and solid‐ state lighting applications. We report on our progress developing efficient, stable QLEDs for full‐color active‐matrix displays, including recent advances in device performance, lifetime and Cadmium‐free QLEDs. Current QLED devices exhibit peak luminance efficiencies exceeding 50 cd/A, luminous power efficiencies greater than 20 lm/W and operational lifetimes exceeding 300 hours at 1,000 nits. Our most recent QLED efficiency results suggest that today's QLED performance is within a factor of two of the theoretical limit.