Researchers from the University of Alabama Huntsville and the University of Oklahoma have found a new method to control the properties of quantum dots using ultrathin layers of metal oxides. A key property of quantum dots, their fluorescence, can change over time with exposure to light and air. The researchers previously found that placing quantum dots of a certain type on nanometer-thin layers of chromium and aluminum oxides significantly altered the dots’ emission efficiency. They have now looked at the behavior of four different types of commercially available quantum dots. Some of the quantum dots had protective shells, while others did not, and some of the dots had cores made of binary materials, while others had ternary material cores. All of the quantum dots had been manufactured by chemical synthesis. The researchers found that ultrathin aluminum oxide could make quantum dots glow brighter, and that the effect was much more significant for quantum dots without protective shells. They also found that while quantum dots with both binary and ternary cores shrink after reacting with the oxygen in air, ternary core dots placed on aluminum oxide glowed brighter despite the shrinkage. As a next step, the researchers plan to investigate how metal oxides might affect the behavior of quantum dots when they are close to metallic nanoparticles.