Letter www.acsami.org
Facile Preparation and Ultrastable Performance of SingleComponent White-Light-Emitting Phosphor-in-Glass used for HighPower Warm White LEDs Xuejie Zhang,† Jinbo Yu,† Jing Wang,*,† Chenbiao Zhu,† Jinhui Zhang,† Rui Zou,† Bingfu Lei,‡ YingLiang Liu,‡ and Mingmei Wu*,† †
Ministry of Education Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510275, China ‡ College of Materials and Energy, South China Agriculture University, Guangzhou, Guangdong 510642, China S Supporting Information *
ABSTRACT: Long lifetime, excellent chromatic stability, and easily obtainable white light are becoming three outstanding challenges faced by the state-of-the-art high-power white LEDs. This study explored a novel single-component white-lightemitting phosphor-in-glass (PiG) for the first time. It has a quantum efficiency of 26.2% and exhibits excellent heatresistance and good humidity-resistance characteristics which are rarely reported in traditional phosphor slurry. A proof-ofconcept warm white LEDs was fabricated by combining PiG with near-ultraviolet chip-on-board (n-UV COB). This method reported in this letter will open a new and simple approach to obtain excellent performance single-component luminescent convertor for advanced high-power white LEDs. KEYWORDS: PiG, single-component, white-light-emitting, high-power white LEDs, stable
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now, several studies regarding of yellow light-emitting YAG:Ce3+-PiG used for blue LED were reported.12−15 However, such a kind of white LEDs device still has pending issues of high CCT and low CRI. To increase CRI, YAG:Ce3+ phosphor is first mixed with green-emitting Lu3Al5O12:Ce3+ and red-emitting CaAlSiN3:Eu2+ phosphors and the mixture of phosphor powder and glass frit is then sintered to obtain multicolor emitting PiG.16−18 Nevertheless, there is a serious reabsorption between randomly mixed red phosphor and green/yellow phosphor, caused by spectral overlapping. This will finally reduce luminous efficacy of white LEDs. To solve this problem, Won Bin Im et al. proposed that geometric reassembling one PiG disk using Lu3Al5O12:Ce3+-based and CaAlSiN3:Eu2+-based half or quarter PiG disk.19 Even though this method efficiently decreased spectral overlap, the complicated preparation process suppresses the actual application. In summary, how to simply obtain white light is still a challenge in the field of PiG-based white LEDs. In this letter, a series of Ca9Gd(PO4)7:Eu2+,Mn2+ (denoted as CGP:Eu2+,Mn2+) phosphors were synthesized and further used to fabricate PiG because of their good chemical stability
igh-power white LEDs used in solid-state lighting, combination of commercial phosphors and n-UV or blue LED, are the mainstream technology of the future general illumination.1−4 However, it should be noted that a high input current (350/750/1000 mA) leads to a high junction temperature (150−200 °C) of the device,5,6 which brings about the deterioration and yellowing of the organic resin (epoxy resin or silicone) and finally raises several issues of white LEDs, including luminous efficacy degradation, the shift of chromaticity, and the reduction of long-term reliability as well as lifetime.7−9 Aiming to solve these problem, luminescent glasses with interesting advantages of excellent heat-resistance and high thermal conductivity, such as white-emitting Ce3+/ Tb3+/Mn2+ tridoped- and tunable emission Eu2+-doped45SiO2−30Li2O−15SrO−5Al2O3−3K2O−2P2O5 (abbreviated as SLSAKP) luminescent glasses, have been studied in our previous work.10,11 However, the quantum efficiencies of these luminescent glass are not high enough because of the nature of noncrystalline materials. To overcome this bottleneck, PiG technology is strongly expected to be a promising way because PiG, a composite of phosphor and glass frit fabricated via a viscous sintering process at a considerably low temperature (
