Quantum dots are clusters of some 1,000 atoms which act as one large « super-atom. » It is possible to accurately design the electronic properties of these dots just by changing their size. However, to create functional devices, a large number of dots have to be combined into a new material. During this process, the properties of the dots are often lost.
Quantum dots are clusters of some 1,000 atoms which act as one large « super-atom. » It is possible to accurately design the electronic properties of these dots just by changing their size. However, to create functional devices, a large number of dots have to be combined into a new material. During this process, the properties of the dots are often lost.
Now, a team led by University of Groningen professor of Photophysics and Optoelectronics, Maria Antonietta Loi, has succeeded in making a highly conductive optoelectronic metamaterial through self-organization. The metamaterial is described in the journal Advanced Materials.
Quantum dots of PbSe (lead selenide) or PbS (lead sulfide) can convert shortwave infrared light into an electrical current. This is a useful property for making detectors, or a switch for telecommunications.
« However, a single dot does not make a device. And when dots are combined, the assembly often loses the unique optical properties of individual dots, or, if they do maintain them, their capacity to transport charge carriers becomes very poor, » explains Loi. « This is because it is difficult to create an ordered material from the dots. »
Ordered layer
Working with colleagues from the Zernike Institute for Advanced Materials at the Faculty of Science and Engineering, University of Groningen, Loi experimented with a method that allows the production of a metamaterial from a colloidal solution of quantum dots.
