Bismuth activated high thermal stability blue-emitting phosphor Na₂Y₂B₂O₇:Bi used for near-UV white-light LEDs

Abstract

A novel blue emitting phosphor Na2Y2B2O7:Bi3+ was synthesized by solid state reaction method. The structure characteristics, concentration, temperature-dependent luminescence and light emitting diode (LED) device performance were systematically studied. Adjustable...

Tuning Emission from Greenish to Blue via Chemical Composition Modulation in Solid Solutions (Sr1–yCay)2Sb2O7:Bi3+ under near-UV Light Excitation

“…Phosphor-converted w-LEDs are a way of generating white light, which is constructed by an individual LED chip and several phosphors. A suitable approach is to integrate blue, green, and red (tricolor) phosphors to realize the purpose of a high color rendering index (CRI). − Unfortunately, w-LEDs assembled with several types of phosphors suffer a loss of luminescence efficiency for reabsorption, and the CRI is getting worse for the different degradation rates of phosphors. The other problem is that the color balance would be broken at the working temperature of 150–200 °C for the different thermostabilities of multiphosphor mixtures.…”

Efficient Broadband Yellow-Green Emission of Vacancy Halide Double Perovskites Through the Ion-Exchanged Strategy

“…We further studied the luminescence mechanism by changing the excitation power and temperature. Prior to this, it should be stated that ns ions are susceptible to the influence of wavelength and temperature to cause different electronic transitions, which are usually manifested as apparent changes in the peak shape and position. , As one can see, excitation and emission spectra are recorded every 10 nm, and they did not show new peaks, and the peak shape remains consistent (Figure c,d). As shown in Figure e, the temperature-dependent spectra of CH 0.99 T 0.01 C are recorded at every 30 K. As the temperature decreases, the PL intensity gradually weakens, which is because high temperature promotes nonradiative recombination in the crystal lattice. , The temperature-dependent pseudocolor map further shows the emission wavelength and PL intensity (Figure f).…”

Constructing a Model for Tuning the Thermal Quenching Properties of Bismuth-Doped Phosphors by Energy-Gap Modulation

“…The position of the excited state energy level depends on the degree of cleavage of the Bi 3+ energy level. The greater the crystal field splitting energy, the stronger the crystal field and the greater the degree of energy-level splitting, resulting in a decrease in the 3 P 1 energy level . Contrarily, the 3 P 1 energy level rises.…”

“…The greater the crystal field splitting energy, the stronger the crystal field and the greater the degree of energylevel splitting, resulting in a decrease in the 3 P 1 energy level. 42 Contrarily, the 3 P 1 energy level rises. The crystal field splitting energy refers to the energy difference between the highest energy level and the lowest energy level; its strength depends on a series of effects, including the bond length between the activator and the ligand, the symmetry of the activator-ion site, molecular overlap, and the degree of covalence.…”