Semiconductors at the heart of electronic and optoelectronic devices require high-purity materials and involve costly manufacturing processes. In contrast, emerging applications often require a combination of the electronic and optical properties of inorganic semiconductors and cost-efficient solution-based fabrication techniques suitable for industrial-scale manufacturing. In recent years, colloidal quantum dots (QDs) have become a versatile platform for integrating proven inorganic semiconductor materials into high-performance optoelectronic devices by using solution-based fabrication methods at ambient conditions instead of costly, ultra-high-vacuum, high-temperature device manufacturing processes.
Colloidal quantum dots are a type of semiconductor nanocrystals with a typical size in the range of 2-20 nm. They comprise a crystalline inorganic semiconductor core coated with a shell of organic molecules. Due to the presence of inorganic and organic constituents, these colloidal nanocrystals combine the chemical processibility of molecular compounds with the semiconductor materials’ well-understood electronic and optical properties.
In the future, colloidal quantum dots could enable conceptionally new photoconversion strategies arising from the unique physical properties of the quantum-confined colloidal nanomaterials. For example, the process of charge carrier multiplication in QDs can generate multiple electron-hole pairs from a single absorbed photon.