3 Types of Quantum Dots

Core-Type Quantum Dots

Core-type quantum dots are produced from a single semiconductor material. Their size ranges between 2 and 10 nanometres. The emitted wavelength depends on particle size. Smaller dots emit light at wavelengths in the blue spectrum. Larger dots emit light at wavelengths corresponding to red colours. Synthesis is conducted under standard laboratory conditions. The structure accommodates electrons efficiently. They are employed in lighting and imaging devices. Researchers select core-type dots for their consistent performance.

Typically, core-type quantum dots use materials such as cadmium selenide. This material produces a clean light spectrum. They perform well in prototype display devices. Experiments indicate that adjusting particle size alters the emission wavelength quantitatively. The resulting material allows precise control of light output. Many electronic devices depend on these measured properties.

Core-Shell Quantum Dots

Core-shell quantum dots include an additional semiconductor layer covering the core. The external layer is typically composed of a different semiconductor. The shell increases light emission efficiency and overall stability. It reduces the risk of degradation due to oxidation.

For example, a cadmium selenide core may be overlaid with a zinc sulphide shell. This configuration reduces defect frequency and produces higher luminescence. The shell protects the core from environmental oxidation. Core-shell quantum dots are used in display panels, LED backlight units and lighting systems where precise colour output is required. Their structure permits improved longevity in operational devices. Studies have measured extended operational lifetimes in displays employing core-shell quantum dots.

Alloyed Quantum Dots

Alloyed quantum dots incorporate two or more semiconductor materials in the core. This mixed composition permits tuning of the emission wavelength and physical properties. Adjusting the alloy ratio yields specified emission characteristics. Alloyed dots demonstrate consistent performance under temperature variations. The alloying process balances the attributes of the constituent materials and produces stable emission profiles.

In some cases, alloys contain cadmium, zinc and selenium. Researchers employ this mixture to reduce the proportion of toxic materials relative to traditional cadmium-based dots. Alloyed quantum dots are applied in solar panels and biomedical imaging where precise light emission is required. They are suitable for systems that demand exact tuning. The designed composition provides specific optical properties while minimising toxicity.

Comparison Data Table

Below is a table that shows key differences among the three types of quantum dots.

Applications of Quantum Dots

Quantum dots are utilised in both everyday devices and technical instruments. They are incorporated into high-definition televisions and computer monitors. Such devices achieve precise colour reproduction. For instance, televisions using quantum dot technology demonstrate improved colour precision and energy efficiency when compared with older LCD systems given that display characteristics are quantified. Electronics companies have integrated quantum dots in new products.

1. In lighting, quantum dots are used to fabricate energy-efficient LED lights. They emit strong and consistent light. Experiments have recorded an increase in operational lifespan in LED systems.

2. In biomedical research, quantum dots are employed for imaging and molecular tracking. They label cells with detectable light. Research studies record improved tracking of cellular functions, thereby enhancing diagnostic methods.

3. Solar panels incorporate quantum dots to improve light absorption. Recent designs add a quantum dot layer that increases absorption efficiency by up to 20% when compared with traditional panels. This improvement is significant for photovoltaic installations and portable solar units.

4. Additional applications include sensors and lasers. Quantum dots provide adjustable light emissions that are measurable in controlled experiments. Lasers using quantum dots generate stable light beams for industrial and research uses.

Conclusion

This article described three types of quantum dots and their features. Core-type quantum dots contain a single semiconductor material. Core-shell quantum dots include an additional protective layer. Alloyed quantum dots combine several semiconductor materials to adjust optical emission. Their applications include display devices, solar panels and biomedical imaging. Further details are available at Stanford Advanced Materials (SAM).

Frequently Asked Questions

F: What are quantum dots fabricated from?
Q: Quantum dots are fabricated from semiconductor materials such as cadmium selenide, zinc sulphide or combinations thereof.

F: Are quantum dots used in solar panels?
Q: Yes, quantum dots are integrated into solar panels to increase light absorption and energy conversion rates.

F: Do core-shell quantum dots have a longer operational lifetime than core-type quantum dots?
Q: Yes, the protective layer reduces oxidation and degradation, thereby extending the operational lifetime.