Quantum Dots

Quantum dots (QDs) are semiconductor nanocrystals, typically 2-10 nanometers in diameter, exhibiting unique size-dependent optical and electronic properties due to the quantum confinement effect. This phenomenon means that as the QD's size changes, its bandgap and thus the color of light it absorbs and emits also changes.

Smaller QDs emit blue light, while larger ones emit red light, offering precise color tunability. They are often composed of materials like CdSe, InP, perovskites, or silicon, and frequently feature core-shell structures (e.

g., CdSe/ZnS) for enhanced stability and quantum yield.

Key manufacturing techniques include colloidal synthesis (wet chemistry, scalable), molecular beam epitaxy (MBE, high precision for thin films), and chemical vapor deposition (CVD). Their exceptional properties, such as narrow emission spectra, broad absorption, and high photoluminescence, make them invaluable for a range of advanced applications.

These include next-generation QLED displays and TVs, where they provide superior color purity and energy efficiency. In solar cells, QDs can boost efficiency by absorbing a wider spectrum of light and enabling multiple exciton generation.

For medical uses, their tunable fluorescence and small size make them ideal for high-resolution imaging, diagnostics, and targeted drug delivery, with non-toxic silicon QDs being particularly promising.

Furthermore, quantum dots are being explored as potential qubits for quantum computing, a critical area for India's National Mission on Quantum Technologies. While challenges like toxicity (for Cd-based QDs) and scalability exist, ongoing research, particularly in India, is focused on developing safer, more efficient, and cost-effective quantum dot technologies.