Summary
Heavy metals are a major public health concern and their on-site detection in water supplies is not well served by existing lab techniques. We develop a new multi-modal platform comprising functionalized quantum dots of two-dimensional materials (2D-QDs) for the sensing of four highly-toxic heavy metal pollutants (arsenic, cadmium, lead and mercury). The zero-dimensional nature of quantum dots brings essential properties necessary for fluorescence-based chemical sensing of heavy metals in the field. We focus on one type of 2D material, molybdenum disulfide (MoS2), which is a direct band gap semiconductor when produced as a monolayer. To fabricate and functionalize the 2D-QDs, we expose flakes of MoS2 suspended in a solution to a pulsed laser. This technique allows us to simultaneously functionalize the 2D-QDs, so that they become sensitive to a specific pollutant metal, and control their fluorescence wavelength, so that 2D-QDs functionalized for different target metals will produce distinguishable optical signals. By combining multiple types of functionalized 2D-QDs into a single solution capable of simultaneously identifying various heavy metals, we expect to advance a range of applications that require a field-deployable solution. These include for example, rapid contaminant point source identification, and water analysis of heavy metals in developing countries where conventional equipment is too costly.

Figure 1. Functionalized quantum dots of a 2D material are being developed for fluorescence-based chemical sensing of toxic heavy metal pollutants.
Related Content

Qubits and Quantum Effects in Biology
It is unknown whether biological processes make direct use of quantum effects, as opposed to depending merely on the influence of quantum physics on chemical bonding and molecular structure.
June 1, 2017

Composite Superconductors for Improved Quantum Coherence
Summary Conventional superconductors have trouble performing well in magnetic fields required for electron spin resonance (ESR) – based quantum information processing applications. We can, however, use proximity engineering to select desired properties from different materials and combine them for improved superconducting performance in magnetic fields — an improvement that would have strong implications for […]
December 12, 2018

Inverse Photoemission Spectroscopy of Quantum Materials
Summary Quantum materials that exhibit strong electron correlations lead to phenomena, such as superconductivity and topologically protected states, that are important for quantum computation, sensing, and other applications. For example, we may utilize symmetry protected topological states to make qubits that are robust against decoherence, while advances in high temperature superconductors may significantly reduce […]
September 20, 2018

Magnetoelectric Coupling in New Composite Multiferroic Nanostructures as High-Density Quantum Multistate Memory Elements
Summary Magnetoelectric multiferroics are materials that exhibit correlated ferroelectric and ferromagnetic properties (i.e., a magnetoelectric effect). The resulting ability of these materials to simultaneously store data in electric polarization and magnetic moment could increase data storage density and data processing speed while reducing energy consumption. This project aims to design and fabricate new composite multiferroic […]
February 1, 2023