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Innovative Light-Driven Technique Enhances Quantum Dot Production

A recent development from North Carolina State University introduces a novel technique that harnesses light to adjust the optical characteristics of quantum dots, streamlining the process while also enhancing energy efficiency and environmental sustainability without sacrificing material integrity.

“The Nobel Prize in Chemistry awarded in 2023 for the discovery of quantum dots underscores their vast potential in various applications,” notes Milad Abolhasani, the lead author of the study and ALCOA Professor of Chemical and Biomolecular Engineering at NC State. “Quantum dots play a crucial role in technologies such as LEDs, solar cells, and displays, as well as in quantum technologies. To modify their optical properties, it is essential to adjust the bandgap of the quantum dots, which represents the minimum energy needed to free an electron from its bound state, directly affecting the emitted light’s color.”

As Abolhasani explains, “Traditional bandgap tuning methods for perovskite quantum dots typically involve chemical alterations or high-temperature processes, both of which can be energy-draining and may create inconsistencies in the material’s final properties.”

The research team has developed a technique that utilizes light to initiate the reaction, reducing the energy input required and ensuring a high degree of precision in the outcomes.

Initially, the researchers worked with green-emitting perovskite quantum dots, immersing them in a solution enriched with either chlorine or iodine. The solution is then guided through a microfluidic system equipped with a light source.

This microfluidic setup is vital as it facilitates meticulous control over the reaction process by providing consistent light exposure across small solution volumes, approximately 10 microliters for each reaction droplet. Such small volumes allow the light to permeate the entire sample, leading to rapid photochemical reactions throughout.

Exposure to light instigates reactions that shift the green-emitting perovskite quantum dots toward the blue spectrum in the presence of chlorine, while the addition of iodine causes them to approach the red spectrum.

According to Abolhasani, “By governing the energy we infuse into the sample through light control, we can precisely manage the bandgap. This enables fine-tuning of the bandgap with remarkable accuracy.”

“The process operates in minimal reaction volumes and is swift, which results in the efficient production of perovskite quantum dots with tailored bandgaps, surpassing the capabilities of previous methods,” Abolhasani adds.

“Our approach represents a sustainable avenue for creating high-quality perovskite quantum dots utilizing light. We are currently advancing our efforts to scale up production for their application in optoelectronic devices,” he concludes.

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