Quantum dots (QDs) are nanoscale semiconductor particles that exhibit unique size-dependent optical and electronic properties, making them highly suitable for next-generation electronic sensor applications. Their exceptional features—such as high surface-to-volume ratio, tuneable bandgap, high quantum yield, and stability under ambient conditions—enable enhanced sensitivity, selectivity, and miniaturization in sensor design.

In electronic sensors, QDs are primarily utilized for detecting chemical, biological, and environmental analytes through mechanisms such as fluorescence quenching, charge transfer, and energy transfer. The ability of QDs to emit bright, stable, and tuneable fluorescence upon excitation is a major advantage in optical sensing platforms. When functionalized with selective recognition elements (e.g., antibodies, aptamers, or molecularly imprinted polymers), QDs can serve as highly responsive and specific probes for the detection of gases, toxins, pathogens, or biomolecules.

Gas sensors based on QDs, such as those detecting ammonia, nitrogen dioxide, or volatile organic compounds, have demonstrated superior performance due to the fast electron transport and increased reactivity at the nanoscale. For example, QD-decorated metal oxides improve sensitivity and response time by facilitating charge carrier mobility and enhancing surface interactions with target gas molecules.

In biosensing, QDs are increasingly integrated into electronic biosensors for diagnostics, particularly in point-of-care and wearable technologies. QDs can transduce biological interactions into measurable electrical or optical signals with high resolution. For instance, QD-based field-effect transistor (FET) biosensors have been employed for real-time detection of glucose, DNA, and proteins at ultra-low concentrations, benefiting from the QDs’ ability to modulate charge transport upon analyte binding.

Moreover, QDs are being explored in multiplexed sensing applications due to their size-dependent emission wavelengths, which allow simultaneous detection of multiple targets in a single assay. This capability is crucial for complex diagnostics, such as in cancer biomarker panels or infectious disease screening.

Despite their potential, practical implementation of QD-based sensors faces challenges, including issues related to QD toxicity (particularly cadmium-based QDs), stability in complex environments, and large-scale fabrication. Current research is focused on developing non-toxic, robust QDs (e.g., carbon or silicon-based) and scalable integration techniques compatible with flexible electronics and microfluidic systems.

In summary, quantum dots represent a powerful nanotechnology platform for the advancement of electronic sensors, offering enhanced sensitivity, selectivity, and versatility for diverse applications ranging from environmental monitoring to medical diagnostics.

Keywords: quantum dots, sensors, nanotechnology, fluorescence, biosensors, gas detection, field-effect transistors.

Ts. Dr. Intan Helina Hasan
Sensor Nanotechnology Research Program
Functional Nanotechnology Devices Laboratory

Date of Input: 17/07/2025 | Updated: 17/07/2025 | roslina_ar