Luminescent Thermometry by a Y/Eu Binary Layered Rare‐Earth Hydroxide (LRH) via In Situ Intercalation with Neutral Terbium(III) Complexes

Abstract

Temperature‐sensitive luminescent materials have aroused great interest for practical applications in optical sensors. Layered rare‐earth hydroxides (LRHs) possess rich interlayer chemistry and adjustable composition; thus, they are the promising candidates for designing functional materials, usually through an ion exchange process. Herein, the intercalation of neutral TbIII complex rather than ion exchange was successfully performed in situ into the gallery of Y/Eu binary LRHs by using a hydrothermal process. Interestingly, the swollen LRHs are chameleon luminophores, exhibiting color emissions from green to pink that were tunable through variations in temperature ranging from 77 to 450 K. Because of the highly sensitive and temperature‐dependent emissions, novel optical temperature sensors for 1D and 2D thermal imaging were fabricated by employing the chameleon luminophores, which displayed luminescence capable of reversibly undergoing repeated thermocycles. The present work opens up new fields in layered inorganic materials.

Layered terbium hydroxides for simultaneous drug delivery and imaging

“…Structurally, LRHs are similar to LDHs but the component sheets are more complicated because the rare-earth metal ions form two distinct coordination polyhedra, with 8 and 9 vertices. 47 The ability of LRHs to exhibit magnetic and fluorescent properties arising from the rare-earth metal ions they contain has fostered increasing interest in their applications in medical imaging, 48,49 as optical sensors, [50][51][52][53] and as tuneable phosphors. 54,55 In addition, like LDHs, their layered structure also allows LRHs to be used in conventional applications such as sequestration and catalysis.…”

Uniform colloidal spheres for RE3BO6 (RE = Eu‐Yb, Y) and excitation‐dependent luminescence of Y3BO6:Eu3+ red phosphor

“…The PLE spectrum, recorded by monitoring the red emission at 613 nm ( 5 D 0 → 7 F 2 transition of Eu 3+ ), exhibits a broad transition band ranging from 200 to 300 nm, with a maximum at ~209 nm and two broad shoulders at ~234 nm, ~270 nm (Figure A). These are the transitions by charge transfer (CT), that is, the electronic transition from the 2 p orbital of O 2− to the 4 f orbital of Eu 3+ activators . Because yttrium ions occupy nine independent crystallographic positions, Eu 3+ ions, that replace Y 3+ ions, are randomly distributed in these sites, resulting in various CT band centers arising from the different Eu–O bond lengths .…”

“…These are the transitions by charge transfer (CT), that is, the electronic transition from the 2p orbital of O 2− to the 4f orbital of Eu 3+ activators. [25][26][27] Because yttrium ions occupy nine independent crystallographic positions, Eu 3+ ions, that replace Y 3+ ions, are randomly distributed in these sites, resulting in various CT band centers arising from the different Eu-O bond lengths. 3 The excitation peaks at ~320 nm, ~350-420 nm (with the maximum at ~394 nm), and ~465 nm are the intra-4f electronic transitions of Eu 3+ , which are 7 F 0,1 → 5 H 3 , 5 H 6 , 7 F 0,1 → 5 L 6 , and 7 F 0,1 → 5 D 2 , respectively.…”

“…3 The excitation peaks at ~320 nm, ~350-420 nm (with the maximum at ~394 nm), and ~465 nm are the intra-4f electronic transitions of Eu 3+ , which are 7 F 0,1 → 5 H 3 , 5 H 6 , 7 F 0,1 → 5 L 6 , and 7 F 0,1 → 5 D 2 , respectively. [25][26][27] Interestingly, the intensities of the Eu 3+ transitions at ~394 and ~465 nm are intense except for the dominate peak at ~209 nm, indicating that these spheres can be efficiently excited by the blue light (~465 nm) along with the traditional ultraviolet and near ultraviolet excitation. Upon excitation with ~209 nm (ultraviolet), ~394 nm (near ultraviolet), and ~465 nm (blue) wavelengths light, the emission spectra of Y 3 BO 6 :Eu 3+ spheres all show the typical Eu 3+ emission, which are 5 D 0 -7 F J (J = 1, 2, 3, 4) transitions at ~592 nm, ~613 (627) nm, ~653 nm, and ~708 nm, respectively ( Figure 12B-D).…”

Implanting bismuth in color-tunable emitting microspheres of (Y, Tb, Eu)BO3 to generate excitation-dependent and greatly enhanced luminescence for anti-counterfeiting applications

“…Therefore, the solid-solution phosphor always exhibits orange-red emission at 590 nm. While under exposure to UV light, YBO 3 : Tb 3+ displays the typical green emission at~546 nm ( 5 D 4 → 7 F 5 transition of Tb 3+ ), and color-tunable photoluminescence can be found in solid solution phosphor of Y/Tb/Eu ternary system through an efficient energy transfer from Tb 3+ to Eu 3+ ions [18][19][20]. Recently, it was reported that doping Bi 3+ in rare-earth borates could effectively manipulate the synthetic/thermal stable temperature [21].…”