Researchers at the Barcelona Institute of Science and Technology have developed LEDs comprising infrared colloidal quantum dots that enable high efficiency and low cost CMOS integration.

Colloidal quantum dots are extremely small semiconductor particles which are as small as a few nanometers in size. With their small size, CQDs offer unique optical and electronic properties including absorbing and emitting light. Moreover, their properties change with their size and shape; smaller quantum dots emit in the blue range while larger quantum dots emit in the red.

(Image: Samsung)

The use of colloidal quantum dot in LEDs has become one of the key ingredients as the implementation of these nanocrystals in devices for optical sensing in the short-wave and mid- infrared can enhance applications including surveillance, night vision, and environmental monitoring.

A research team from ICFO-Institut de Ciencies FotoniquesIn at the Barcelona Institute of Science and Technology developed colloidal quantum dots infrared emitting LEDs, which have achieved an external quantum efficiency of 7.9% and an unprecedented power conversion efficiency of 9.3%.The result was published in Nature Nanotechnology on December 3rd, 2018.

The research achievements prove that the engineering of QCD infrared-emitting LEDs at the nanoscale integrated in solar cells can significantly improve the performance efficiency of these devices in the infrared range. The results provide opportunities for a wider range of application such as on-chip spectrometers for food inspection, environmental monitoring, as well as active imaging systems for biomedical or night vision applications.