Colloidal quantum dots make LEDs shine bright in the infrared

ScienceDaily | 12/3/2018 | Staff
The ICFO team has reported a solution processed nanocomposite system comprising infrared colloidal quantum dots that also meets these criteria and at the same time offers low cost and facile CMOS integration. Colloidal Quantum Dots (CQDs) are extremely small semiconductor particles or crystals, as small as a few nanometers in size, and because of their size they are capable of having unique optical and electronic properties. They are excellent absorbers and emitters of light, having their properties change as a function of their size and shape: smaller quantum dots emit in the blue range while larger quantum dots emit in the red.

The use of colloidal quantum dot (CQD) light-emitting diodes (LEDs) has become one of the key ingredients in leading technologies such as, for example, 3rd generation, solution processed, and inorganic solar cells. The implementation of these nanocrystals in devices for optical sensing in the short-wave and mid- infrared have triggered a vast number of applications including surveillance, night vision, product, process and environmental monitoring and spectroscopy.

Study - Nature - Nanotechnology - ICFO - Researchers

In this recent study published in Nature Nanotechnology, ICFO researchers Santanu Padhan, Francesco Di Stasio, Yu Bi, Shuchi Gupta, Sotirios Christodoulou, and Alexandros Stavrinadis, led by ICREA Prof. at ICFO Gerasimos Konstantatos, have developed CQD infrared emitting LEDs, which have achieved unprecedented values in the infrared range, with an external quantum efficiency of 7.9% and a power conversion efficiency of 9.3%, a value never attained before with these type of devices.

The key feature of this work has been the development of a CQD composite structure engineered at the suprananocrystalline level to reach unprecedently low electronic defect density. Prior efforts in suppressing electronic defects in CQD solids have been primarily been based on chemical passivation of the CQD surface, something that could not solve the problem in PbS QDs. The researchers at ICFO took an...
(Excerpt) Read more at: ScienceDaily
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