European researchers demonstrate quantum dots light up under strain
The traditional operating principle of quantum dots is based on the so-called quantum confinement effect, where the particle size determines the color of the emitted light. The new strategy relies on a completely different physical mechanism; a strain induced electrical field inside the quantum dots. The field is created by growing a thick shell around the dots. The researchers were able to compress the inner core, creating the intense internal electric field. The field becomes the dominating factor in determining the emission properties.
The result is a new generation of quantum dots whose properties are beyond those enabled by quantum confinement alone which not only broadens the application scope of the well-known CdSe/CdS material set but also of other materials.
"Our findings add an important new degree of freedom to the development of quantum dot-based technological devices," explained the researchers. "For example, the elapsed time between light absorption and emission can be extended to be more than 100 times longer compared to conventional quantum dots, which opens the way towards optical memories and smart pixel new devices. The new material could also lead to optical sensors that are highly sensitive to the electrical field in the environment on the nanometer scale”.
Reference
Christodoulou S, Rajadell F, Casu A, Vaccaro G, Grim JQ, Genovese A, Manna L, Climente JI, Meinardi F, Rainò G, Stöferle T, Mahrt RF, Planelles J, Brovelli S, Moreels I. Nat Commun. 2015 Jul 29; 6:7905. doi: 10.1038/ncomms8905.
Related articles and links:
www.nature.com/ncomms/2015/150729/ncomms8905/full/ncomms8905.ht
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