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In this paper the white-light-emitting Gd2P4O13:Tm3+-Dy3+ phosphors were synthesized via high temperature solid-state reaction method. The X-ray diffraction of the Gd2P4O13:Tm3+-Dy3+ phosphors were performed. Concentration quenching of Gd2P4O13 with Tm3+ - doped ions was studied in detail. The luminescence excitation, emission and decay measurements were performed. Energy transfer between Tm3+ and Dy3+ have been studied. The phosphor Gd2P4O13:Tm3+ exhibit strong blue emission ranging from 440 nm to 470 nm of Tm3+ (3H6 → 1D2) under 359 nm excitation. The emission peak at 456 nm is the luminescence of Tm3+ (1D2 → 3F4). Energy transfer process in the Dy3+-Tm3+ system is proved. This paper includes the color perception analysis of synthesized phosphors. The coordinates of Gd2P4O13:1%Tm3+-3%Dy3+ phosphor is very close to the white-lighting location.

A series of Ce-doped phosphors K3Gd1-xB6O12:xCe3+ (x = 0, 0.005, 0.01, 0.02, 0.03, 0.04) were synthesized by high-temperature solid state reaction method. The luminescence properties were investigated under UV (333 nm) excitation. Under 333 nm light excitation, K3Gd1-xB6O12:xCe3+ exhibits intense blue emission centered at 405 nm, due to the 4f1(2F5/2)→4f°5d1 transition of Ce3+ activator. The optimum doping concentrations was found to be x = 2%. The bi-exponential behavior of the decay curves of phosphor K3Gd0.98B6O12:0.02Ce3+ reveals that the Ce3+ activators can reside in two unique crystallographic distinct sites (Gd3+ sites), which fits well with the XRD analysis. One may expect that K3Gd1-xB6O12:xCe3+ has the potential be used as a green phosphor activated by near near-UV light.

In this paper we report the photo-trapping effect of photogenerated charge in a few numbers of silicon nanocrystals (Si-NCs) embedded in SiO2 layer tunnel oxide of small area single electron photodetector (Photo-SET or nanopixel). Using Current-Voltage measurements under illumination (photo-I–V) we find the photo-active traps effect in inversion zone at room temperature. Random Telegraphic Signal under illumination (photo-RTS analysis) confirms that is a photo-generated active trap inside into tunnel oxide layer (Ephoto-act∼ 0.2 eV) and capture section: σ∼8.72 × 10−17 cm2). Moreover, an increasing about 10 pF in capacity’s values in the inversion region for inverse high voltage applied under photo-excitation at low temperature have been marked using photo-Capacitance-Voltage (photo-C–V) measurements. This result confirms the contribution of photo-active traps to better dots photo-charged. The increase of light excitation time-duration, increase the hysteresis width. At 100 μW optical power and 595 nm wavelength, the hysteresis width has their saturation for a 0,05V/s romp speed, and consequently, SiO2 will not behave a dielectric, but as a metal. So we make think that total capacity of structure no more corresponds to the capacity related to the oxide, but to all structure capacity values. The nanopixel photo-detection time (∼400 s) estimated from the flat band evolution in time is affected by photo-active oxide traps presence.

CaREAl 3 O 7 :Eu 3+ (RE = Y, Gd, Lu) phosphors have been prepared by sol–gel method. The effect of rare earth ions on the luminescence of CaREAl 3 O 7 :Eu 3+ were investigated. In CaREAl 3 O 7 :Eu 3+ system the emission intensity can be ordered as follows: Y ≈ Gd > Lu. Moreover, under 393 nm light excitation all compounds exhibited strong luminescence of 5 D 0 – 7 F 2 at 617 nm. The excitation spectra implied that these phosphors can effectively absorb the emission of near UV-LED chips. All the results indicate that these phosphors are promising red-emitting phosphors pumped by near-UV light.