Scientists at JILA, a joint venture of NIST and the University of Colorado, have found a way to suppress the “blinking” problem in quantum dots. Quantum dots are tiny semiconductor particles that emit light, but they tend to turn on and off unpredictably, reducing their usefulness in applications like biomedical research and quantum encryption.
By bathing the dots in a solution of an antioxidant chemical, the JILA team increased the rate of photon emission four- to fivefold. This approach dramatically reduced the average time delay between excitation and photon emission from 21 nanoseconds to 4 nanoseconds while reducing the probability of blinking up to 100 fold.
The chemical appears to attach to imperfections on the surface of the quantum dots, blocking electrons from being trapped and preventing the dots from blinking off. This discovery could make quantum dots more sensitive as fluorescent tags in biomedical tests and more reliable sources of single photons for quantum encryption.
The research was funded in part by the National Science Foundation and NIST.
Source: https://www.nist.gov/news-events/news/2008/01/jila-solves-problem-quantum-dot-blinking
Keywords: Quantum Dots, Photon Emission, Blinking Suppression, Radiative Lifetimes, Nonradiative Lifetimes
