23 November 2017
Tricking metal atoms into producing more light
Published online 30 March 2017
Scientists use ‘a chemical trick’ to alter light emissions from metal atoms.
Nanoclusters of metal atoms are promising for their fluorescence, low toxicity and stability under light. However, the underlying causes of these features have not been adequately scrutinized, something that a new research from Saudi Arabia and China is trying to change by studying the metal atoms under different light and heat conditions to fine-tune their emissions.
A simple chemical trick makes self-assembling nanoclusters of copper atoms increase their emission in solution, says the new study.1
“This study offers a new viewpoint on the origin and control of emission, providing a new way to tailor the emission properties of metal nanoclusters,” says lead author Zhennan Wu from the King Abdullah University of Science and Technology (KAUST), Saudi Arabia. “They could be used as emitting materials for illumination and display applications.”
The scientists created defects-rich nanosheets of copper atoms which self-assembled in an organic solvent. Besides creating the defects on the surface, the solvent accelerated self-assembly of the nanosheets and modified their surface properties, significantly enhancing light emission.
When exposed to light at different wavelengths, the nanosheets displayed what scientists term ‘photoluminescence’, a phenomenon in which light is absorbed and then emitted. The sheets produced various emissions in different colors — bright yellow and blue-green — and were able to retain strong emissions for nearly two months in the solution.
The properties leading to the emissions were found to be temperature-dependent. Dialing down the temperature increased the intensity of the light emissions, according to the researchers.
- Wu, Z. et al. Contribution of metal defects in the assembly induced emission of Cu nanoclusters. J. Am. Chem. Soc. http://dx.doi.org/10.1021/jacs.7b00773 (2017)