Cadmium Sulfide Nanoparticles Decorated with Au Quantum Dots as Ultrasensitive Photoelectrochemical Sensor for Selective Detection of Copper(II) Ions

Abstract

Anomalous ingestion of copper has significant adverse effects and shows acute toxicity in living organisms. Recently, photoelectrochemical (PEC) method has attracted much attention as a platform for a Cu 2+ ion sensor because of its high sensitivity, selectivity, low-cost, and accurate selection compared to other conventional methods. In this work, stepwise hydrothermal and in situ chemical approaches for synthesizing cadmium sulphide nanoparticles (CdS NPs) for decorating gold quantum dots (Au QDs) are presented, along with a notable PEC performance. The amount of Au QDs loaded on the CdS NPs had a significant influence on the PEC performance. CdS NPs-Au QDs-2 with 1.0 mmol% of Au QDs demonstrated an exceptional photocurrent density of 350.6 µA cm −2 , which was 3.7, 2.2, and 2.0-fold higher than those of CdS NPs, CdS NPs-Au QDs-1 (0.75 mmol%), and CdS NPs-Au QDs-3 (1.25 mmol%), respectively. Femtosecond transient absorption dynamics of the ground state recovery showed a buildup time of 243 fs for Au and 268 fs for CdS, which were assigned to cooling of the photoexcited electrons. For CdS NPs-Au QDs, the transient spectrum was dominated by a signal from CdS with no contribution from Au. The fast buildup dynamic was absent in CdS-Au, indicating a rapid transfer of the photoexcited electrons from CdS to Au before cooling down. Unquestionably, the CdS NPs-Au QDs-2 photoelectrode response upon Cu 2+ detection showed the lowest limit of detection of 6.73 nM in a linear range of 0.5-120 nM. The selectivity of CdS NPs-Au QDs-2 toward Cu 2+ ions in lake and tap water was also studied, which suggested that CdS NPs-Au QDs-2 is promising as a photoactive material for PEC-based environmental monitoring and analysis.

UV‐Light Photoelectrochemical Sensor Based on the Copper Tetraamino‐Phthalocyanine‐modified ITO Electrode for the Detection of Nifedipine in Drugs and Human Serum

“…16 PEC sensors combine the advantages of optical methods and chemical sensors due to their simultaneous application of light irradiation and electrochemical detection. 18 PEC sensors have been successfully applied to the detection of environmental pollutants, 19 food additives, 20 drug content, 21 pesticide residues, 22,23 and enzymes. 18 PEC sensors have been successfully applied to the detection of environmental pollutants, 19 food additives, 20 drug content, 21 pesticide residues, 22,23 and enzymes.…”

Autofluorescent Hyperbranched Poly(amide amine) as Effective Fluorescent Probe for Label-free Detection of Copper(II) Ions

“…Up to now, a number of fluorescent sensors based on quantum dots, 13,14 metal nanoparticles, 15,16 and fluorescent organic dyes 17 have been employed to detect Cu 2+ . Nevertheless, these fluorescent probes suffer from some defects such as photobleaching of fluorescent dye, high toxicity and expensive cost of noble metal sources, [18][19][20][21] which has further restricted their widespread application.…”

A photoelectrochemical biosensor for determination of DNA based on flower rod-like zinc oxide heterostructures

“…Increasing attention on PEC biosensors is a result of their good sensitivity and desirable analytical performance [2]. Because of the source separation for excitation and detection, PEC sensors can remove some undesirable background signals [3,4]. The marriage of optical methods and electrochemical approaches endows PEC sensors with small detection backgrounds and greatly high sensitivity [3][4][5][6].…”

“…Because of the source separation for excitation and detection, PEC sensors can remove some undesirable background signals [3,4]. The marriage of optical methods and electrochemical approaches endows PEC sensors with small detection backgrounds and greatly high sensitivity [3][4][5][6]. Owing to low background signal and desirable sensitivity, PEC bioassays have offered various elegant routes for biological recognition events [7,8].…”