Science Daily November 22, 2021
Quantum dots tendency to blink off at random intervals has hampered its use for biochemical applications. Researchers at MIT have come up with a way to control this unwanted blinking by firing a beam of mid-infrared laser light for an infinitesimal moment which eliminates the quantum dot’s blinking for a relatively long period. According to the researchers the cause of the blinking phenomenon probably has to do with extra electrical charges, such as extra electrons, attaching to the outer part of the quantum dots, altering the surface properties providing alternative pathways for the extra energy to be released instead of by emitting light. When zapped with a burst of mid-infrared light, the extra charges tend to get knocked off the surface, allowing the quantum dots to produce stable emissions and stop their blinking. According to the researchers zapping is a general process which might turn out to be useful for dealing with anomalous intermittency in some other devices, such as in nitrogen vacancy centers in diamond. They believe this method can be applied to other emitters. The effect may not be limited to the mid-infrared pulses, the same principle could also extend to terahertz frequencies…read more. TECHNICAL ARTICLE
Experimental scheme and single dot verification. Credit: Nature Nanotechnology (2021)Â