Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Nov 21;8(48):45483-45494.
doi: 10.1021/acsomega.3c05222. eCollection 2023 Dec 5.

SrAl2O4:Eu2+,Dy3+ Long Afterglow Phosphor and Its Flexible Film for Optomechanical Sensing Application

Akshay M Achari  1 , Vanishree Perumalsamy  1 , Godavarthi Swati  1 , Ayush Khare  2
Affiliations

SrAl2O4:Eu2+,Dy3+ Long Afterglow Phosphor and Its Flexible Film for Optomechanical Sensing Application

Akshay M Achari et al. ACS Omega. .

Abstract

Mechanoluminescence is an unusual phenomenon in which a material emits electromagnetic radiation due to any deformation caused by mechanical force. In the present study, highly flexible mechanoluminescent films of SrAl2O4:Eu2+,Dy3+ have been prepared by incorporating phosphor in a poly(vinyl alcohol) hydrogel using optimized ratios of dimethyl sulfoxide (DMSO):water as solvents. Upon introducing DMSO as a solvent along with water, flexibility and mechanical properties such as tear resistance and hardness of hydrogel were enhanced to a large extent. Samples prepared with DMSO:water (80:20 wt %) exhibit a higher tensile strength of 13.4 MPa, elongation strain of about 620%, and higher transparency. This hydrogel transmits enough energy to SrAl2O4:Eu2+,Dy3+ upon mechanical impact. For the proof of concept, mechanoluminescence (ML) testing was done, and it was found that the emission intensity of samples is linearly dependent on the force of impact. Room temperature photoluminescence (PL) emission from SrAl2O4 is attributed to 5d-4f transitions of Eu2+ ions with an afterglow lifetime of ∼5 h. Emission intensity was found to persist at ∼90% of its actual value even at a temperature of ∼100 °C, indicating the high thermal stability of phosphor. Furthermore, thermogravimetric analysis was carried out to study the thermal stability of phosphor-incorporated films. Weight loss during TGA occurs in three steps: loss of solvent, decomposition of the cross-linking branches from the PVA backbone, and decomposition of PVA. The as-prepared film showed excellent flexibility, thermal stability, and good mechanical strength, evidencing it as a potential candidate for self-powered flexible impact sensing applications.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
XRD patterns of Eu2+- and Dy3+-doped strontium aluminate synthesized by (a) solid-state reactions and (b) hydrothermal-assisted coprecipitation synthesis.
Figure 2
Figure 2
SEM images of SrAl2O4 as synthesized by (a) high-temperature flux-assisted sintering and the (b) hydrothermal-assisted coprecipitation method.
Figure 3
Figure 3
EDAX spectrum of the as-synthesized Eu2+,Dy3+-doped strontium aluminate sample.
Figure 4
Figure 4
FTIR spectra of strontium aluminate phosphor prepared by (a) solid-state reactions and the (b) hydrothermal-assisted coprecipitation method.
Figure 5
Figure 5
Photoluminescence (a) excitation and (b) emission spectra of samples prepared via solid-state reactions and the hydrothermal-assisted coprecipitation method and (c) their corresponding CIE chromaticity diagram.
Figure 6
Figure 6
(a) Time-resolved photoluminescence of as-prepared rare-earth-doped strontium aluminate synthesized via solid-state reactions and hydrothermal-assisted coprecipitation methods. (b) Afterglow emission captured using a digital camera at different time intervals.
Figure 7
Figure 7
(a) Temperature-dependent photoluminescence emission spectra of SrAl2O4:Eu,Dy prepared by solid-state reactions. Insets (i) and (ii) represent the variation of emission intensity with respect to temperature and Arrhenius plot for calculating the activation energy (Eg), respectively. (b) Emission spectra of the sample prepared by the hydrothermal-assisted coprecipitation method. Insets (i) and (ii) represent the variation of emission intensity with respect to temperature and Arrhenius plot for calculating the activation energy (Eg), respectively.
Figure 8
Figure 8
(a) Mechanoluminescence (ML) testing setup, (b) ML output of SrAl2O4 with respect to the drop height, (c) graphical representation of ML intensity with respect to height, and (d) theoretical relation between kinetic energy of the steel ball and the drop height.
Figure 9
Figure 9
Phosphor-incorporated flexible films (a) under UV irradiation and (b) persistence emission from the sample under dark conditions (the inset represents the film under ambient lightning).
Figure 10
Figure 10
(a) Tensile strength measurements of the as-prepared PVA hydrogel with varied concentrations of water and DMSO. (b) Dog-bone-shaped mold used to make the film with required dimensions according to the ASTM standard D412. (c) Stress and strain variation with DMSO concentrations.
Figure 11
Figure 11
Thermogravimetric analysis of strontium aluminate phosphor-incorporated hydrogel films of varying ratios (w/w) of DMSO:H2O.
Figure 12
Figure 12
Schematic representation of phenomena of mechanoluminescence when SrAl2O4:Eu2+,Dy3+ is subjected to a mechanical impact.
See this image and copyright information in PMC

References

    1. Wencel D.; Abel T.; McDonagh C. Optical Chemical pH Sensors. Anal. Chem. 2014, 86 (1), 15–29. 10.1021/ac4035168. - DOI - PubMed
    1. Liu T.; Pagliano F.; van Veldhoven R.; Pogoretskiy V.; Jiao Y.; Fiore A. Integrated Nano-Optomechanical Displacement Sensor with Ultrawide Optical Bandwidth. Nat. Commun. 2020, 11 (1), 2407.10.1038/s41467-020-16269-7. - DOI - PMC - PubMed
    1. Zhang Z.; Dai X.; Shan G.; Li G.; Li X.; Liu X.; Qin F. A Low Cost UV-IR Dual Wavelength Optical Sensor with Chirp Modulation for in-Situ Chemical Oxygen Demand Measurements. Sens. Actuators B Chem. 2022, 371, 13253810.1016/j.snb.2022.132538. - DOI
    1. Bacon F.The Advancement of Learning; Macmillan & Company, Limited, 1898; Vol. 1.
    1. Fan Y.-T.; Yang Y.-L.; Li T.; Yuan J.-Y.; Li Q.-L.; Zhao J.-T.; Wan D.-Y.; Zhang Z.-J. Enhanced Mechanically Induced Red-Light Emitting Novel Mechanoluminescence Materials for Ultrasonic Visualization and Monitoring Applications. J. Mater. Chem. C 2021, 9 (18), 5868–5875. 10.1039/D0TC05739H. - DOI