Non-cytotoxic Dy3+ activated La10W22O81 nanophosphors for UV based cool white LEDs and anticancer applications

K Naveen Kumar; L Vijayalakshmi; Jiseok Lim; Jungwook Choi

doi:10.1016/j.saa.2022.121309

Non-cytotoxic Dy³⁺ activated La₁₀W₂₂O₈₁ nanophosphors for UV based cool white LEDs and anticancer applications

Spectrochim Acta A Mol Biomol Spectrosc. 2022 Oct 5:278:121309. doi: 10.1016/j.saa.2022.121309. Epub 2022 May 1.

Authors

K Naveen Kumar¹, L Vijayalakshmi², Jiseok Lim³, Jungwook Choi⁴

Affiliations

¹ School of Mechanical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea. Electronic address: knaveenphy@gmail.com.
² School of Automotive Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea.
³ School of Mechanical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea. Electronic address: jlim@yu.ac.kr.
⁴ School of Mechanical Engineering, Chung-Ang University, Seoul 06974, Republic of Korea. Electronic address: choij@cau.ac.kr.

PMID: 35550991
DOI: 10.1016/j.saa.2022.121309

Abstract

White-light-emitting La₁₀W₂₂O₈₁ (LWO): xDy³⁺ (0.5 ≤ x ≤ 10 mol%) nanocrystalline phosphors were developed by a facile hydrothermal assisted solid-state reaction. X-ray diffraction (XRD) pattern indicated that the prepared samples adopted orthorhombic crystal structures. The agglomeration of uniform nanorods was identified from the FE-SEM analysis of the optimized LWO: 1.5 mol% Dy³⁺ nanocrystalline phosphors. Additionally, transmission electron microscope, scanning transmission electron microscopy, selected area electron diffraction, and X-ray photoelectron spectroscopy were employed to explore the surface morphology, size, interplanar distance, and chemical composition with valence states of the LWO: 1.5 mol% Dy³⁺ phosphors, respectively. By exciting with 387 nm, the LWO: Dy³⁺ emission spectra showed two intense peaks at 476 nm (⁴F_9/2→⁶H_15/2) and 571 nm (⁴F_9/2→⁶H_13/2) and a shoulder peak at 659 nm (⁴F_9/2→⁶H_11/2). Optimum emission intensity was achieved for 1.5 mol% Dy³⁺ in the LWO host lattice. The luminescence quenching beyond 1.5 mol% Dy³⁺ is attributed to the dipole-dipole interactions when the Dy³⁺ (donor) and Dy³⁺ (acceptor) ions are at a critical distance of 58.53 Å. Photometric studies were conducted to evaluate the performance and practical applicability of the phosphors. The CIE chromaticity diagram suggests that the LWO: 1.5 mol% Dy³⁺ nanophosphor conspicuously exhibits cool white light. Therefore, this material could be a promising and potential white light-emitting nanocrystalline phosphor material for white light emitting diodes (LEDs) under near-UV excitation. In addition, the toxicity of the optimized nanophosphor in normal WI-38 lung fibroblast cells and MCF-7 breast cancer cells was examined. Surprisingly, LWO: 1.5 mol% Dy³⁺ nanophosphor was found to be non-cytotoxic to normal cells, but extremely toxic to cancer cells. Therefore, the nanophosphor materials can be considered potential candidates for biomedical applications, particularly for cancer treatment.

Keywords: Anticancer; Cytotoxicity; Nanophosphors; Photoluminescence; White-light emission.

MeSH terms

Dysprosium* / chemistry
Light
Luminescence*
Phase Transition
X-Ray Diffraction

Substances

Dysprosium