A research team from the University of Chicago in the United States has demonstrated a new method for obtaining mid infrared emission using colloidal quantum dots (QDs)

According to reports, a research team at the University of Chicago in the United States recently demonstrated a new method for obtaining mid infrared emission using colloidal quantum dots (QDs), which may open up new applications for mid infrared light sources.

Colloidal quantum dots are a type of semiconductor nanocrystal material that provides a promising approach for the synthesis of light sources in large quantities through wet chemical solution processing technology.

The electroluminescence of colloidal quantum dots in the visible light range has been highly efficient and cost-effective, but other wavelengths have been proven to be more challenging so far, especially in the mid infrared region.

The Philippe Guyot SiOnnest Laboratory (PGS Laboratory) at the University of Chicago specializes in the study of nanocrystalline quantum dots generated by colloidal synthesis chemistry. A colloidal quantum dot with significantly improved emission characteristics in the mid infrared band has been developed and its research results have been published in the journal Nature Photonics.

Mid infrared light source
Xingyu Shen from PGS Laboratory commented, "This cost-effective and easy-to-use method of manufacturing infrared light sources using quantum dots may be very useful. This discovery may ultimately lead to significantly cheaper mid infrared LEDs and lasers, or new technological applications.

The above work is based on the previous research on the manufacturing and performance of quantum dot devices in PGS laboratory, including efforts to improve the size distribution of nanoparticles and the development of nanocrystalline quantum dot infrared detectors, which may be comparable to commercial devices at extremely low costs.

In 2022, the research team demonstrated the first mid infrared colloidal quantum dot LED based on mercury telluride (HgTe), which has semiconductor properties and stability, facilitating infrared emission. The team pointed out at the time that this quantum dot "has the potential to break the extremely high 'cost/gram' of infrared imaging through exciting new manufacturing processes.

In the new project, the team further studied the manufacturing technology and luminescence methods of colloidal quantum dots, inspired by the established laser emission cascade method, where electrons pass through a series of different energy levels and emit a portion of energy in the form of light at each level.

According to the PGS laboratory, so far this cascade technology has never been achieved using colloidal quantum dots. The laboratory has created a black "ink" of HgTe nanocrystals, which are "coated" on a substrate and illuminated by an electric current.

According to a paper published by the team in the journal Nature Photonics, the colloidal quantum dot emits a quantum efficiency of 4.5% μ The mid infrared light of m is close to commercial epitaxial cascaded quantum well light-emitting diodes. Through further optimization, this cascading method may surpass existing methods.

We are very excited about this possibility, "Guyot SiOnnest said." This is one of the best examples of potential applications of colloidal quantum dots. More applications can be achieved through other materials, but this system architecture really works because of quantum mechanics. I think it is driving the field forward in a very interesting way.

Source: Sohu