TY - GEN
T1 - DNT detection using microspheres coated with NaYF4-Yb3+,Er3+-nanocrystals functionalized with PAA/PAH layers
AU - Amrithanath, Abhishek Kottaram
AU - Wei, Heming
AU - Krishnaswamy, Sridhar
N1 - Funding Information:
This research was funded by the Office of Naval Research project #N00014-16-1-3021 with Dr. Ignacio Perez as program manager.
Publisher Copyright:
© 2018 SPIE.
PY - 2018
Y1 - 2018
N2 - In this paper, we demonstrate the fabrication of a chemical sensor for 2,4-dinitrotoluene (DNT), based on an opticalfiber- microsphere coated with upconversion nanocrystals functionalized with layers of polyelectrolytes - poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH). The design consists of a microsphere, which supports whispering-gallery-modes (WGM), coupled to an optical fiber. The NaYF4-Yb3+,Er3+ nanocrystals have a bright fluorescence around 550 nm and 650 nm when irradiated with 980 nm, which is enhanced by the WGM. When functionalized with PAA/PAH layers, these nanocrystals can be coated on the microsphere with control over layer thickness. The presence of DNT on the surface of the microsphere quenches the fluorescence as the absorption spectrum of DNT has peaks in 500 - 600 nm. The effect of concentration of the analyte on the magnitude of quenching has been studied. The paper discusses the design, fabrication and characterization of the chemical sensor.
AB - In this paper, we demonstrate the fabrication of a chemical sensor for 2,4-dinitrotoluene (DNT), based on an opticalfiber- microsphere coated with upconversion nanocrystals functionalized with layers of polyelectrolytes - poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH). The design consists of a microsphere, which supports whispering-gallery-modes (WGM), coupled to an optical fiber. The NaYF4-Yb3+,Er3+ nanocrystals have a bright fluorescence around 550 nm and 650 nm when irradiated with 980 nm, which is enhanced by the WGM. When functionalized with PAA/PAH layers, these nanocrystals can be coated on the microsphere with control over layer thickness. The presence of DNT on the surface of the microsphere quenches the fluorescence as the absorption spectrum of DNT has peaks in 500 - 600 nm. The effect of concentration of the analyte on the magnitude of quenching has been studied. The paper discusses the design, fabrication and characterization of the chemical sensor.
KW - DNT
KW - Microsphere
KW - erbium
KW - polyelectrolyte
KW - upconversion
KW - upconversion nanoparticles
KW - whispering gallery mode
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U2 - 10.1117/12.2296465
DO - 10.1117/12.2296465
M3 - Conference contribution
AN - SCOPUS:85049592758
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Nano-, Bio-, Info-Tech Sensors, and 3D Systems II
A2 - Varadan, Vijay K.
PB - SPIE
T2 - Nano-, Bio-, Info-Tech Sensors, and 3D Systems II 2018
Y2 - 5 March 2018 through 7 March 2018
ER -