New method for synthesizing colloidal quantum dots

Colloidal quantum dots (CQD), whose particles are only several nanometers in size, have been an increasingly important research subject because of their highly tunable properties, which affords them a wide variety of applications as semi-conductors. 

A recent study¹, published in Nature Materials, reports a new method of synthesizing CQD that may help overcome some challenges, such as lack of uniformity in CQD particle sizes, and the inhomogeneity of energy landscape in CQD solids. 

Previous synthesis methods caused the random packing of the particles and consequently inconsistent energy and particle size. This led to losses in open-circuit voltage and thus prevented CQD from being fully harnessed in applications such as optoelectronic devices, which are devices operating on light and electricity, and include lasers, photo-detectors, and solar cells.  

Researchers were now able to modify the CQD synthesis procedure that had been poorly controlled and had once contributed to rendering CQD less efficient.

The new method, which synthesizes CQD in a solution via a substitution reaction, insures that the CQD films are fused homogenously, and allows for an advantageously high packing density. The CQD obtained were found to exhibit reduced energy losses, and an enhanced light-to-electricity conversion efficiency of 11.28%. 

Ted Sargent, corresponding author of the study, and professor of nanotechnology at University of Toronto in Canada, says this can substantially enhance the performance of solar cells, and help pave the way for their large-scale production. 

“The work is the result of a very fruitful and longstanding collaboration with colleagues at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia,” he adds.

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