[21p-C101-1~15] 13.8 Optical properties and light-emitting devices

▲ [21p-C101-10] New (oxy)nitride phosphors discovered by single-particle-diagnosis approach and time-resolved spectroscopy

〇Jian Xu¹, Shiro Funahashi¹, Kohsei Takahashi¹, Takayuki Nakanishi¹, Naoto Hirosaki¹, Takashi Takeda¹ (1.NIMS)

Keywords:Phosphor, Single-particle-diagnosis approach, Time-resolved spectroscopy

Benefiting from a novel phosphor screening method based on single crystal X-ray diffractometry and single-particle spectroscopy, i.e., the single-particle-diagnosis approach, a new Eu²⁺-activated cyan-emitting oxynitride phosphor (Si_2.5Al_9.5O_0.5N_12.5:Eu²⁺) was discovered. Although there are no obvious crystalline sites able to accommodate larger Eu²⁺ ions in the host, the time-resolved streak imaging of a single crystalline particle indicates that the cyan-emitting band peaking at ~500 nm with a relatively narrow full-width at half-maximum (FWHM) of ~61 nm exhibits a typical Eu²⁺ fluorescent lifetime (~0.39 μs) in oxynitrides. Besides, slight lifetime variation (0.32 μs vs. 0.47 μs) between shorter wavelength region (450-500 nm) and longer wavelength region (500-550 nm) of the Eu²⁺ emission band may suggest two different crystalline environments around Eu²⁺. This sialon-polytypoid cyan-emitting phosphor with efficient excitability at 365 nm may find its potential application as an all-inorganic color-converter in near-ultraviolet (NUV) excited wLEDs.