Synthesis and luminescent properties of novel thermal-stable orangish-red-emitting LnNbO 4 : Sm 3+ (Ln=La, Y) phosphors
- PDF / 2,516,818 Bytes
- 8 Pages / 595.276 x 790.866 pts Page_size
- 21 Downloads / 179 Views
Synthesis and luminescent properties of novel thermal‑stable orangish‑red‑emitting LnNbO4: Sm3+ (Ln=La, Y) phosphors F. B. Xiong1,2 · F. X. Xu1 · H. F. Lin1 · Y. P. Wang1 · E. Ma3 · W. Z. Zhu1 Received: 7 July 2020 / Accepted: 18 October 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Sm3+-doped LnNbO4 (Ln=La, Y) phosphors were obtained by high-temperature solid-state reaction. The crystal structure of LnNbO4:Sm3+ (Ln=La, Y) was characterized by X-ray diffraction. Luminescent properties of those phosphors were investigated by diffuse reflection spectra, excitation spectra, as well as emission spectra. The emission spectra of those phosphors consisted of several orangish-red emission bands around 550–670 nm upon the excitation at 405 nm, and the luminescent NbO4: Sm3+. The 87.0% energy transfer efficiency from emission intensity of L aNbO4: Sm3+ was much stronger than that of Y 3+ 3+ the host to S m ions was observed in L aNbO4: Sm phosphor. Furthermore, the critical transfer distance was calculated and the CIE chromaticity coordinates of LaNbO4: Sm3+ samples were in the range of orangish-red. The fluorescence lifetimes of as-prepared LaNbO4: Sm3+ samples were within the millisecond range and the temperature-dependent luminescence indicated LaNbO4: Sm3+ was highly thermal-stable. Our results indicated that novel orangish-red-emitting L nNbO4: Sm3+ (Ln=La, Y) phosphors were expected to have great potential in white LEDs. Keywords Luminescence · Orangish-red phosphors · Concentration quenching · White LED
1 Introduction At present, electrical energy consumption is one of the important aspects in energy consumption, and a large part of the electrical energy utilization is attributed to all kinds of illuminations [1]. Therefore, more and more attention has been paid to the research on energy saving. The nextgeneration light source of solid-state lighting, white lightemitting diodes (LEDs), have their merits of compactness, high efficiency, long-lasting life, environment-friendliness and low energy consumption [2–5]. Nowadays, the commercial white LEDs are consisted of blue LED and yellow phosphor. Because of the absence of red phosphors, those white LEDs exhibits cold white light accompanied * F. B. Xiong [email protected] 1
Department of Optoelectronics, Xiamen University of Technology, Xiamen 361024, China
2
Fujian Provincial Key Laboratory of Optoelectronics Technology and Devices, Xiamen University of Technology, Xiamen 361024, China
3
Fujian Institute of Research On the Structure of Matter, Chinese Academy of Science, Fuzhou 350002, China
with poor color rendering index (CRI) and high correlated color temperature (CCT) [6, 7]. Therefore, the solution of adding Ce3+/Eu2+-doped red phosphors to improve the CRI of white LEDs has been suggested [8, 9]. While, those red phosphors have the drawback of a relatively high manufacturing expense, because of severe synthesis conditions such as high temperature, high pressure and vacuum. Another solution to
Data Loading...
