Author ORCID Identifier
Document Type
Thesis
Date of Award
2025
Degree Name
Master of Science (MS)
Department
Chemistry
First Advisor
Chaoyang Jiang
Abstract
Inorganic luminescent materials are extensively used in anti-counterfeiting. However, their unauthorized replication remains a significant concern. Recently, lanthanide-doped upconversion nanoparticles (UCNPs) have gained increasing interest as promising anti-counterfeit materials. While prior research has largely emphasized multicolor emissions in the visible spectrum, their near-infrared (NIR) capabilities are yet underutilized. In this work, we designed novel UCNPs that emit light in both visible and NIR regions from a single nanoparticle. By co-doping Yb³⁺, Er³⁺, and Tm³⁺ ions into a hexagonal NaYF4 matrix, emissions at 543 nm (green), 657 nm (red), and 802 nm (NIR) are achieved under 980 nm excitation. We found that adjusting Tm³⁺ concentration can modulate the intensity ratio between NIR and visible emissions, as well as overall green and red emissions. Power-dependent luminescence study confirms that the upconversion emission is a result of a biphotonic process. The intensity modulation is related to an energy transfer process between the dopants. Finally, the anti-counterfeiting application of these UCNPs is demonstrated via a multilevel security label, highlighting their potential as functional materials for advanced information encoding and counterfeit deterrence. ProQuest, Part of Clarivate About ETD Administrator Contact Us Manage Cookies Terms & Conditions Privacy Policy Cookie Policy Accessibility Copyright ©
Subject Categories
Chemistry
Keywords
Anticounterfeiting Lanthanide ion Multicolor luminescence Near-Infrared emission Tunable emission Upconversion nanoparticles
Number of Pages
83
Publisher
Uiversity of South Dakota
Recommended Citation
KALAPALA, GOPALA KRISHNA MURTHY, "SYNTHESIS AND CHARACTERIZATION OF TRIPLY DOPED UPCONVERSION NANOPARTICLES FOR ANTI-COUNTERFEITING APPLICATIONS" (2025). Dissertations and Theses. 369.
https://red.library.usd.edu/diss-thesis/369