Relationship between microstructure and the achieving of the single-band red upconversion fluorescence of Er3+/Yb3+ codoped crystallites

Pure red upconversion emission from Yb3Al5O12 phase doped with high Er3+ concentration

“…2(d) and (e) and Table 1 prove that one of every four Yb 3+ ions was replaced by one Er 3+ ion at YbAG crystal. Phase Yb 2 O 3 dissolved with Er 2 O 3 has no upconversion emission due to the con- centration quench [9]. It can be concluded that the upconversion emission must be generated from YbAG phase.…”

“…The fact that the rare earth ions have a plenty of energy levels provoking these ions emitting a wide range spectra covering near infrared (NIR) to ultraviolet (UV), however, this excellent phenomenon itself means a negative point which makes it difficult to obtain single color emission such as pure red upconversion emission which has potential applications in color display and visual search [7]. Dong, Liu, et al [8][9][10][11][12] reported high emission intensity ratio of the red to the green (R/G) in Er 3+ /Yb 3+ co-doped upconversion materials with the excitation of 980 nm LD, but the purity was not high enough. Liu et al [9,13] reported that the high concentration of Yb 3+ ion would bring high value of R/G.…”

“…Dong, Liu, et al [8][9][10][11][12] reported high emission intensity ratio of the red to the green (R/G) in Er 3+ /Yb 3+ co-doped upconversion materials with the excitation of 980 nm LD, but the purity was not high enough. Liu et al [9,13] reported that the high concentration of Yb 3+ ion would bring high value of R/G. According to the Bai et al [14], it is possible to obtain single color upconversion emission when the concentration of Yb 3+ and Er 3+ ions is optimized.…”

Generation of Pure Green Up-Conversion Luminescence in Er3+ Doped and Yb3+-Er3+ Co-Doped YVO4 Nanomaterials under 785 and 975 nm Excitation

“…Thereby, via using these aforementioned equations, the CCT values for the emissions of Er 3+ -doped and Er 3+ /Yb 3+ -codoped YVO 4 nanomaterials excited with different wavelengths (785 or 975 nm) are calculated and presented in Table 1. As disclosed, by changing the dopant content and excitation wavelength, CCT values vary in the range of 6018 to 6334 K. Additionally, it is worth noting that the intensity of the red emission band of Er 3+ ( 4 F 9/2 → 4 I 15/2 ) may also be influenced by the synthesis method of the luminescent material [51,52,55,71,72]. In general, based on the available literature data, it can be concluded that thermal treatment, i.e., high temperatures used during the solid-state method or post-synthesis calcination favor green emissions-namely, the relative intensity of the red emission band is significantly lower compared to the green emission bands [51,52,55,71,72].…”

Simultaneously tunable luminescence and magnetic properties in bifunctional NaYF4: Yb3+/Er3+ microcrystals

“…Up-conversion (UC) materials are those materials that can convert near-infrared emission into visible or ultra-violet emission. They have wide spread applications in various fields such as bio-sensors, bio-imaging, environment monitoring [1,2], information storage [3,4], anti-counterfeiting [5][6][7] and solar cells [8,9], and thus attracted a tremendous amount of attention for the past decade [10][11][12]. These trivalent lanthanide-doped ions have unique spectral and magnetic properties and a broad application prospects in many areas [13,14].…”