Structure evolution and photoluminescence of Lu₃(Al,Mg)₂(Al,Si)₃O₁₂:Ce³⁺ phosphors: new yellow-color converters for blue LED-driven solid state lighting

Abstract

This paper reports the development of new phosphors using the chemical unit cosubstituting solid solution design strategy. Starting from Lu3Al5O12, the Al 3+ -Al 3+ couple in respective octahedral and tetrahedral coordination were simultaneously substituted by a Mg 2+ -Si 4+ pair forming the Lu3(Al2-xMgx)(Al3-xSix)O12:Ce 3+ (x=0.5-2.0) series; as a result, the CeO8 polyhedrons were compressed and the emission got red-shifted from green to yellow together with the boradening. The evolution of the unit cell, the local structural geometry as well as the optical property of Ce 3+ in these garnet creations, in response to the gradual Mg-Si substitution for Al-Al, were studied by combined techiniques of structural refinement and luminescencent measurements. The new composition Lu2.97Ce0.03Mg0.5Al4Si0.5O12 was comprehensively evaluated ragarding its potential application in blue LED-driven solid state white lighting: the maximum emission is at 550 nm under λex=450 nm; the internal and external quantum efficiency can reach 85 % and 49 %, respectively; one-phosphor-converted wLED lamp fabriacted using the as-prepared phosphor exhibits the luminous efficacy of 105 lm/W, correlated color temperature of 6164 K and color rendering index (Ra) of 75.6. The as-developed composition series is open for further optimization to enhance the competeness for commercial consideration.

Red phosphor based on Eu3+-isoelectronically doped Ba2SiO4 obtained via sol–gel route for solid state lightning

“…[1][2][3] In this context, LED lights stand out due to their relative ease of device manufacture and versatility of application mainly in digital displays, liquid crystal devices, headlight vehicles, road lights, public and residential lighting.…”

Chromaticity-Tunable and Thermal Stable Phosphor-in-Glass Inorganic Color Converter for High Power Warm w-LEDs

“…Corresponding to the parity allowed Ce 3+ : 4 f -5 d transitions, the PL spectra present a broadband emission, while the PLE spectra show a wide excitation band as well [16,17,18]. Due to a larger crystal field splitting of the Ce 3+ 5 d levels in the silicate garnet, the emission spectrum of this phosphor was redshifted compared to the commercially available phosphor YAG:Ce 3+ .…”

The Preparation and Optical Properties of Novel LiLa(MoO4)2:Sm3+,Eu3+ Red Phosphor

“…Hence this color cannot meet indoor light requirements which require warm white light and an excellent CRI [5]. In addition, the blue chip InGaN and yellow phosphor possess a different failure rate and in the case of long working hours this may cause chromatic aberration and reduced white performance [6,7,8,9,10]. To solve this problem, researchers have developed red, green and blue emission phosphors using near ultraviolet (NUV: 350~410 nm) excitation [11,12].…”