Abstract：To address the critical issues of severe environmental pollution, high production costs, and low utilization efficiency of rare-earth resources in conventional rare-earth fluorescent materials, an eco-friendly and cost-effective europium(Ⅲ) complex-based composite fluorescent material, Eu(TTA)3(TPPO)2@CaCO3, has been successfully synthesized using nano-sized calcium carbonate (CaCO3) as a carrier. By substituting traditional highly corrosive alkaline reagents (e. g., sodium hydroxide, aqueous ammonia, and triethylamine) with nanoCaCO3, this europium(Ⅲ) complex composite was fabricated under mild reaction conditions. The reaction system's pH was stably maintained between 6.93 and 7.23, eliminating the generation of highly alkaline wastewater associated with conventional methods. A series of composite fluorescent materials (m1~m5) was prepared using EuCl3·6H2O, 2-thenoyltrifluoroacetone (HTTA), and triphenylphosphine oxide (TPPO) as precursors by varying the CaCO3 dosage (1~5 g). Material structures were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). The europium complex Eu(TTA)3(TPPO)2(ETT) was successfully incorporated into CaCO3 while retaining its crystalline structure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that at 1 g CaCO3 loading, micron-sized ETT crystals (2~6 μm) persisted, whereas increasing the CaCO3 dosage to 5 g (m5) yielded a uniform nanoscale composite structure. TEM-EDS confirmed the presence of Eu, F, P, and S onCaCO3 surfaces, verifying ETT attachment. Fluorescence spectroscopy demonstrated that the composite material exhibited maximum excitation intensity at 383 nm and emitted at 617 nm (5D0→7F2 transition), characteristic of Eu3+ red emission. The m1 sample achieved an absolute quantum yield of 48.05%, comparable to pure ETT (48.70%). Even at high CaCO3 loading (m5), the quantum yield remained at 40.29%, indicating minimal luminescence sacrifice. Fluorescence lifetime decay analysis indicated three distinct coordination environments for Eu3+, influenced by CaCO3 interaction. Application tests demonstrated that coating the m1 sample onto a 395 nm LED chip produced a red LED with 99.9% color purity and a brightness of 27 140 cd·m-2, showcasing excellent performance. This approach exploits the alkaline and carrier properties of nano CaCO3 to simultaneously neutralize the reaction system's pH and enable efficient rare earth complex loading, reducing organic ligand requirements while suppressing particle aggregation. Thus, it offers a novel approach to developing cost-effective, environmentally friendly rare-earth fluorescent materials.
Key words：CaCO3; Rare earth complex; Core-shell material
[1] Guo X, Sun J, Li X, et al. Luminescence, 2021, 36(6): 1476.
[2] Luo P, Zhou S K, Xiao X Z, et al. Progress in Organic Coatings, 2023, 185: 107920.
[3] Wang L D, Zhao Z F, Wei C, et al. Advanced Optical Materials, 2019, 7(11): 1801256.
[4] Zhang M L, Zhao C P, Song J Q, et al. Materials Chemistry Frontiers, 2023, 7(1): 160.
[5] He Y Z, Tian Z Y, Gu Z J, et al. Land Degradation & Development, 2024, 35(18): 5533.
[6] Zhang X M, Zhang W L, Yu H, et al. Journal of Luminescence, 2020, 228: 117648.
[7] Lü Y G, Song C X, Zhang Y, et al. Journal of Alloys and Compounds, 2010, 492: 259.
[8] Jordan N, Thoenen T, Spahiu K, et al. Coordination Chemistry Reviews, 2024, 510: 215702.
[9] Shuai Y T, Peng R, He Y Z, et al. Sensors and Actuators B: Chemical, 2023, 384: 133625.
[10] Sun L N, Qiu Y N, Liu T, et al. ACS Applied Materials & Interfaces, 2013, 5(19): 9585.
[11] Zhao Y, Yan B. Journal of Colloid and Interface Science, 2013, 395: 145.
[12] TAO Dong-liang, CUI Yu-min, QIAO Rui, et al(陶栋梁，崔玉民，乔 瑞，等). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2011, 31(3): 723.
[13] JIN Feng, ZHANG Wen-jun, TAO Dong-liang, et al(金 凤，张文军，陶栋梁，等). Chinese Journal of Luminescence(发光学报), 2015, 36(7): 782.
[14] Song M M, Tao D L, Luo G H, et al. Journal of Luminescence, 2018, 203: 292.
[15] Jiang G P, Song L L, Tao D L, et al. Journal of Rare Earths, 2020, 38(11): 1165.
[16] Jiang G P, Ma Y H, Zhang S H, et al. Materials & Design, 2023, 233: 112300.
[17] Gujar R B, Verma P K, Ansari S A, et al. New Journal of Chemistry, 2019, 43(34): 13675.
[18] Zhan X H, Xiao Z L, Zhan H H, et al. Journal of Rare Earths, 2009, 27(3): 368.
[19] Cho Y S, Huh Y D. Materials Research Bulletin, 2016, 78: 58.
[20] Rajendran M, Devi R, Mund S, et al. Journal of Materials Chemistry C, 2021, 9(42): 15034.
