[22p-D316-1~16] 13.8 Optical properties and light-emitting devices

▲ [22p-D316-4] Revisiting the Eu2+ emission in CaAlSiN3 (CASN) red phosphor by time-resolved spectroscopy

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

Keywords:Phosphor, Time-resolved spectroscopy, Laser lighting

Motivated by the fast development of high-power solid-state lighting, in particular under extremely high-power density laser excitation, trying to understand the saturation mechanism of LED phosphors becomes an urgent topic considering the further improvement of laser lighting devices. Herein, by utilizing the time-resolved streak imaging, we investigate the famous red LED phosphor: CASN:Eu under extremely high-power laser excitation. The almost constant lifetime variation at 77 K of Eu²⁺: 5d excited state when increasing the peak power density of pulsed laser from ~10⁴ to ~10⁷ W/mm² may indicate different saturation mechanism of widely applied LED phosphors. Besides, at 4 K, CASN:Eu exhibits a clear multi-band emission feature while almost disappears at 500 K, which may indicate different crystal field environments around Eu²⁺ in CASN host lattices.