A commercial approach for the fabrication of bulk and nano phosphors converted into highly efficient white LEDs

Abstract

A novel approach for the comparative study of bulk and nano phosphors converted into highly efficient white LEDs.

New emerging rare-earth free yellow emitting 2D BCNO nanophosphor for white light emitting diodes

“…The estimated external quantum efficiency (EQE) of the 2D yellow emitting BCNO nanophosphor is as high as 89%, compared to some rare earth YAG:Ce for WLEDs applications. 22 Time-resolved photoluminescence (TRPL) was recorded using a time-correlated single photon counting technique, using a 375 nm EPL pulse diode laser as a source of excitation. The time-resolved photoluminescence decay spectra with fitting curves and their corresponding parameters for the 2D BCNO nanophosphor are shown in Fig.…”

“…do not contain rare-earths but still, these materials contain toxic elements like sulfur, cadmium and selenium. 22 Therefore, the development of a novel ''yellow'' emitting phosphor free from rare-earths as well as toxic metals, which can be synthesized at relatively low temperatures under ambient atmospheric conditions, is desirable for WLEDs applications. A very recent report [I. Akasaki, H.; et al, DOI: 10.1038/nphys3147; Nobel Prize awarded on 7th October 2014] describing the invention of efficient blue light-emitting diodes, which enabled bright and energy-saving white light sources, could potentially reignite searches for WLEDs applications in a broad range of layered rare-earth free materials.…”

“…Until now, WLEDs heavily relied on rare-earth doped phosphor (YAG:Ce), which are optically pumped by the emission from blue LEDs. 22 The combined effect of electroluminescence from blue LEDs and photoluminescence of phosphors results in white light. Most of the currently used phosphors in WLEDs are oxides, nitrides, sulfides or oxysulfides doped with rare-earth materials.…”

Probing on green long persistent Eu2+/Dy3+ doped Sr3SiAl4O11 emerging phosphor for security applications

“…29 Such characteristics have been previously observed and discussed for other rare-earth oxide systems in our earlier publications. [24][25][26][27][28] This is occur due to the presence of access amount of activators/co-activators in host lattice, which creates lattice contraction effect. As a result, photoluminescence intensity also decreases.…”

“…As a result, photoluminescence intensity also decreases. [24][25][26][27][28] More details about the effect of higher concentration of activator/co-activators have been discussed in photoluminescence section. The particle size of the sample can be estimated using Scherer's formula, it is $800 nm.…”