Synthesis, crystal structure and luminescence properties of a Y₄Si₂O₇N₂:Ce³⁺ phosphor for near-UV white LEDs

Abstract

We studied the crystal structure of Y4Si2O7N2 and the relationship between the crystal structure and the luminescence properties.

Synthesis, Crystal Structure, and Luminescence Properties of Y4Si2O7N2: Eu2+ Oxynitride Phosphors

“…, the crystal structure description of YSiON–HI shows four different coordination environments of Y 3+ in the structure of Y 4 Si 2 O 7 N 2 . There are three seven‐coordination with O and N atoms (Y A , Y B , Y D ) and one six‐coordination (Yc), which is well agreed with the early study . The Shannon radii for six‐ and seven‐coordinated Y 3+ are 1.04 and 1.10 Å, respectively.…”

“…), there are four different Y sites in Y 4 Si 2 O 7 N 2 . The Eu 2+ luminescence greatly depends on the local coordination environments, i.e., coordination numbers, coordination types, and coordination distance . Accordingly, different emission bands of Eu 2+ , originating from the different Y sites, can be formed.…”

“…As a result, the structure and luminescence properties of these (oxy)nitrides‐based phosphors doped with Ce 3+ synthesized by conventional solid‐state reaction are investigated extensively . Within these phosphors, Y 4 Si 2 O 7 N 2 : Ce 3+ phosphor shows a strong blue to green emission under UV excitation . To the best of our current knowledge, no research data are related to Eu 2+ ‐doped Y 4 Si 2 O 7 N 2 phosphor.…”

A double substitution induced Ca(Mg0.8, Al0.2)(Si1.8, Al0.2)O6:Eu2+ phosphor for w-LEDs: synthesis, structure, and luminescence properties

“…In addition, the peak positions of emission spectra (Fig.9a) exhibit an obvious blue-shift with increasing temperature: the peak positions at 25 and 250°C are 446 and 430 5 nm, respectively. This phenomenon can be ascribed to the thermally active phonon-assisted tunnelling from the excited states of lower energy emission band to those of higher energyemission band in the configuration coordinate diagram [41][42][43] . Fig.…”

Review of GaN Nanostructured Based Devices

“…Recently, GaN LEDs have a great potential in automotive, medical, and display application including indoor, outdoor lighting, and signals. Nowadays, GaN based near-ultraviolet LEDs (NUV-LEDs) have attracted special attention with regard to pumping sources of white LEDs, photo catalysis, spectrometric detector and biochemical sensors [64,65,66,67]. While the demands for efficient blue GaN LEDs are high, the performance of blue GaN LEDs are seriously weakened by the critical problem of efficiency droop which refers to the reduction in internal quantum efficiency at high current densities [68].…”