Novel red-emitting BaGeTeO 6 :Sm 3+ phosphors with high color purity for NUV excited with white LEDs
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Novel red-emitting BaGeTeO6:Sm3+ phosphors with high color purity for NUV excited with white LEDs Fengmin Song1,2 Received: 10 May 2020 / Revised: 5 July 2020 / Accepted: 15 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Sm3+ ions activated B aGeTeO6 phosphors were firstly produced through a method of solid-state synthesis at high temperatures. X-ray diffraction pointed out the pure phase of BaGeTeO6 phosphors. Photoluminescence spectrum of BaGeTeO6:Sm3+ phosphor showed the strong red emission at 647 nm under 404 nm excitation, while the associated absorption peaks were in the near-ultraviolet area. The optimal doped concentration of B aGeTeO6:Sm3+ phosphor was found at 10 mol%. The Commission Internationale de L’Eclairage coordinates of B aGeTeO6:0.10Sm3+ were calculated to be (0.624, 0.375) and the color purity as high as 99.8%. White light-emitting diodes have been fabricated based on the InGaN chip with high color rendering index (CRI, Ra = 90) and good correlated color temperature (CCT = 5396 K). Therefore, S m3+-doped BaGeTeO6 phosphors have potential application in the illumination field.
1 Introduction Recently, the next generation of illumination is regarded as w-LEDs, which have superior characteristics such as high luminous efficiency, energy-saving, environment-friendliness, and long lifetime [1–7]. Presently, the most common way to develop commercial white light is a combination of blue LED chip coated with yellow-emitting Y 3Al5O12:Ce3+ phosphors [8–10]. However, due to the deficiencies in the red spectral emission region, such phosphors resulted in high CCT (CCT > 6000 K) and a low Ra (Ra < 80), thereby limiting the scope of such kinds of w-LEDs to various applications [11, 12]. There has been a continuous effort to overcome the difficulties in a way of mixing red-, green-, and blue-emitting (RGB) phosphors onto a NUV LED chip to obtain white light [13]. For the activator, Sm3+ ion was a highly efficient activator for different inorganic hosts in terms of the orangered emission because of 4f electronic configuration. S m3+ * Fengmin Song [email protected] 1
School of Chemistry and Environmental Science, Shaanxi University of Technology, Hanzhong 723001, People’s Republic of China
Collaborative Innovation Center for Bioresource Comprehensive Development in the Qinling-Bashan Area, 723001 Hanzhong, People’s Republic of China
2
ions showed orange-red emission due to the 4G5/2→6HJ (J = 5/2, 7/2, 9/2, 11/2) transitions. Because of the good overlap between the major excitation peaks of S m3+ ions at ~ 400 nm as well as the emission of NUV LEDs chip, Sm3+-doped phosphors were presented satisfactory luminescence properties and had the application in w-LEDs [14–16]. Recently, tellurate could be viewed as good host matrices due to the low phonon energy approximately from 800 to 900 ( cm− 1) [17]. Some tellurate-based phosphors were reported, such as LiSrBiTeO6:Eu3+ [18], Ca3TeO6:Eu3+ [19], NaMgLaTeO6:Mn4+ [20], and S rBi2TeO7:Eu3+ [2
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