Issue 3, 2021

Phosphorescent MoS2 quantum dots as a temperature sensor and security ink

Abstract

Currently, few phosphorescent materials (PMs) possess a long phosphorescence lasting time and have potential for application in chemical sensors. Herein, we disclose that the incorporation of few-layer molybdenum disulfide quantum dots (FL-MoS2 QDs) into poly(vinyl alcohol) (PVA) matrices leads to the emission of bright green phosphorescence with a long lasting time of 3.0 s and a phosphorescence quantum yield of 20%. This enhanced phosphorescence originates from the formation of O–H⋯S hydrogen bonding networks between the rich sulfur sites of the FL-MoS2 QDs and the hydroxyl groups of the PVA molecules, which not only rigidifies the vibration modes of the FL-MoS2 QDs but also provides an oxygen barrier. Further investigations reveal that the FL-MoS2 QD/PVA composites exhibit a longer phosphorescence lasting time than N,S-doped carbon dots, few layer tungsten disulfide quantum dots, Rhodamine 6G, and Rhodamine B in PVA matrices. Since heat efficiently induced the removal of water moisture from PVA matrices, the FL-MoS2 QD/PVA composites could be implemented for phosphorescence turn-on and naked-eye detection of temperature variations ranging from 30 to 70 °C. By contrast, the carbon dot/PVA composites were incapable of sensing environmental temperature due to their weak hydrogen bonding with the hydroxyl groups of PVA matrices. Additionally, this study reveals the potential of the FL-MoS2 QD/PVA composites as an advanced security ink for anti-counterfeiting and encryption applications. The given results could open a new direction for potential application of two-dimensional quantum dots in phosphorescence-based sensors and security inks.

Graphical abstract: Phosphorescent MoS2 quantum dots as a temperature sensor and security ink

Supplementary files

Article information

Article type
Paper
Submitted
31 avq 2020
Accepted
09 noy 2020
First published
10 noy 2020
This article is Open Access
Creative Commons BY-NC license

Nanoscale Adv., 2021,3, 661-667

Phosphorescent MoS2 quantum dots as a temperature sensor and security ink

M. Madhu, C. Lu and W. Tseng, Nanoscale Adv., 2021, 3, 661 DOI: 10.1039/D0NA00730G

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