Fluorescent ZnO quantum dots synthesized with urea for the selective detection of Cr6+ ion in water with a wide range of concentrations

Zou Tong; Xinxin Xing; Yue Yang; Ping Hong; Zidong Wang; Rongjun Zhao; Xu Zhang; Sijia Peng; Yude Wang

doi:10.1088/2050-6120/ab29c8

Fluorescent ZnO quantum dots synthesized with urea for the selective detection of Cr⁶⁺ ion in water with a wide range of concentrations

Methods Appl Fluoresc. 2019 Jun 26;7(3):035007. doi: 10.1088/2050-6120/ab29c8.

Authors

Zou Tong¹, Xinxin Xing, Yue Yang, Ping Hong, Zidong Wang, Rongjun Zhao, Xu Zhang, Sijia Peng, Yude Wang

Affiliation

¹ School of Materials Science and Engineering, Yunnan University, 650091 Kunming, People's Republic of China.

PMID: 31195378
DOI: 10.1088/2050-6120/ab29c8

Abstract

Nearly monodisperse Zinc oxide (ZnO) quantum dots (QDs) displayed yellow fluorescence were synthesized using urea as dispersant. In this paper, urea-ZnO QDs were used as fluorescent probe to detect Cr⁶⁺ in solution. The emission from the as-synthesized urea-ZnO QDs is selectively quenched when Cr⁶⁺ ions were added. Moreover, there are two linear relationships between the quenching of fluorescence intensity and the Cr⁶⁺ concentrations ranging from 4 μM to 1000 μM, with the detection limit for Cr⁶⁺ at 19.53 nM (on basis of 3σ/slope criterion). The quenching of fluorescence is attributed to aggregation of the QDs and charge transfer between the QDs and Cr⁶⁺ by measurements of transmission electron microscopy (TEM) images, UV-visible absorption spectra and fluorescence lifetime.