Materials for downconversion in solar cells: Perspectives and challenges

Effects of rare-earth (Er, La and Yb) doping on morphology and structure properties of ZnO nanostructures prepared by wet chemical method

Synthesis of ZnO:TiO2 nanocomposites for photocatalyst application in visible light

Controlled structural and compositional characteristic of visible light active ZnO/CuO photocatalyst for the degradation of organic pollutant

Quantum dots (QDs) are now on the verge of widespread adoption in display applications, after 25 years of scientific research and over a decade of commercialization efforts. This is the result of a combination of industry trends such as liquid crystal displays (LCDs) and light emitting diode (LED) backlight units (BLUs), combined with improvements in QD performance and manufacturing that have taken place across the growing QD ecosystem of Universities, National Labs, and private and public companies. As QDs emerge as a viable choice as downconversion materials in LED backlit LCD displays, they have the potential to be employed in several geometries within these otherwise similar display systems. In all geometries, QD LCDs will provide the broadest available color gamut to the user, in addition to potential benefits in power efficiency, brightness, and contrast. This work will summarize QD properties and advantages in such LED backlit LCDs relative to other competitive downconversion materials, as well as compare and contrast the three primary geometries that will likely be explored during the pursuit of a potentially dominant design.

http://ma.ecsdl.org/content/MA2013-02/49/2729.full.pdf

Quantum Dots for LED Downconversion in Display Applications

Influence of doping and annealing temperature on the structural and optical properties of Mg2SiO4:Eu3+ synthesized by combustion method

Enhanced red emission on co-doping of divalent ions (M2+ = Ca2+, Sr2+, Ba2+) in YVO4:Eu3+ phosphor and spectroscopic analysis for its application in display devices

Here in, the synthesis of the terbium doped zinc oxide (ZnO:Tb3+) nanorods via room temperature chemical co-precipitation was explored and their structural, photoluminescence (PL) and thermoluminescence (TL) studies were investigated in detail. The present samples were found to have pure hexagonal wurtzite crystal structure. The as obtained samples were broadly composed of nanoflakes while the highly crystalline nanorods have been formed due to low temperature annealing of the as synthesized samples. The diameters of the nanoflakes are found to be in the range 50–60 nm whereas the nanorods have diameter 60–90 nm and length 700–900 nm. FTIR study shows Zn O stretching band at 475 cm−1 showing improved crystal quality with annealing. The bands at 1545 and 1431 cm−1 are attributed to asymmetric and symmetric C O stretching vibration modes. The diffuse reflectance spectra show band edge emission near 390 nm and a blue shift of the absorption edge with higher concentration of Tb doping. The PL spectra of the Tb3+-doped sample exhibited bright bluish green and green emissions at 490 nm (5D4 → 7F6) and 544 nm (5D4 → 7F5) respectively which is much more intense then the blue (450 nm), bluish green (472 nm) and broad green emission (532 nm) for the undoped sample. An efficient energy transfer process from ZnO host to Tb3+ is observed in PL emission and excitation spectra of Tb3+-doped ZnO ions. The doped sample exhibits a strong TL glow peak at 255 °C compared to the prominent glow peak at 190 °C for the undoped sample. The higher temperature peaks are found to obey first order kinetics whereas the lower temperature peaks obey 2nd order kinetics. The glow peak at 255 °C for the Tb3+ doped sample has an activation energy 0.98 eV and frequency factor 2.77 × 108 s−1.

Photoluminescence and thermoluminescence studies of Tb3+ doped ZnO nanorods

Enhanced luminescence of ZnO:RE3+ (RE=Eu, Tb) nanorods by Li+ doping and calculations of kinetic parameters

This paper reports on the structural, optical and photometric characterization of yttrium gadolinium orthovanadates (Y1−xGdxVO4) doped with Dy3+ for white emission in solid state lighting. A series of orthovanadates were prepared through a low temperature co-precipitation method and further post annealed. The as synthesized phosphor particles revealed a single phase tetragonal structure with space group I41/amd(141). The infrared spectra confirmed the presence of characteristic vibrational bands of orthovanadates. The microscopic images showed elongated particles after annealing and the particle sizes were estimated in the range of 10–50 nm. The band gap of the prepared phosphors, calculated from the corresponding diffuse reflectance spectra was observed to be 3.75 eV and 3.57 eV for YVO4 and GdVO4 respectively. Y1−xGdxVO4:Dy3+ phosphors, illuminated with ultraviolet light exhibited characteristic blue and yellow luminescence corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 transitions of Dy3+ ion. The emission spectra showed the variation in the intensity ratio (Y/B) with Gd3+ ion variation. Furthermore the thermal quenching property, decay analysis and photometric characterizations were also studied in detail and the results indicated the suitability of these phosphors in solid state lighting.

J. Manam

Papers

Influence of doping and annealing temperature on the structural and optical properties of Mg2SiO4:Eu3+ synthesized by combustion method

Enhanced red emission on co-doping of divalent ions (M2+ = Ca2+, Sr2+, Ba2+) in YVO4:Eu3+ phosphor and spectroscopic analysis for its application in display devices

Photoluminescence and thermoluminescence studies of Tb3+ doped ZnO nanorods

Enhanced luminescence of ZnO:RE3+ (RE=Eu, Tb) nanorods by Li+ doping and calculations of kinetic parameters

Structural, optical and special spectral changes of Dy3+ emissions in orthovanadates