Enhancing sensitivity of carbon dots as Fe ion sensor using time-resolved photoluminescence technique

Abstract

Carbon dots are carbon-based nano materials that have been widely used as heavy metal ion detectors to replace quantum dot semiconductors such as CdS, CdSe, and CdTe which are dangerous to the environment. Cdots are known to be used as nanoparticle probe for the detection of heavy metal ions. Since the advantages of Cdots are sensitive and non toxic. Cdots also have some special properties such as biocompatible, high water solubility, and have high luminescence intensity. However, the detection of heavy metal ions using Cdots still have many limitations such as requiring doping materials Several techniques have been used to measure heavy metal by using CDots; however, their sensitivity needs to improve. We propose time-resolved photoluminescence (TRPL) measurement method to detect Fe3+ ions using CDots made of citric acid and urea. We conducted several other detection methods and compare the results to TRPL method. We found that TRPL method provides direct and high sensitivity compared with other methods. Concentration of Fe3+ ions as low as 0.23 nM can be easily detected using TRPL. Our TRPL measurement is also better than inductively coupled plasma optical emission spectrometry (ICP-OES) measurement system.