Jul 29 2010
Scientists from the Brookhaven National Laboratory of the U.S. Department of Energy have displayed the capability to perk up the intensity of light emanated by individual quantum dots by 20 times by linking gold nanoparticles with individual semiconductor quantum dots.
The precision method will allow scientists to modify and study the optical characteristics of quantum dots subsequently leading to improved solar energy conversion devices, light -controlled electronics and biosensors.
The precision technique builds nano-sized structures by making use of short DNA strands as a highly specific glue to link particles which has two strands with corresponding pairings of bases that fuse in a definite manner and by varying the lengths and the matching pieces, and affixing the whole process on an assembly surface, construction of individual nano clusters can be precisely controlled.
Metallic materials augment the optical characteristics of quantum dots by restraining or boosting photoluminescence, depending on a range of factors, like the size and shape of the materials and the distance between them and the beam wavelength used to induce photo excitation.
The scientists selected two wavelengths for testing purposes one near to the plasmon resonance range and the other outside this range. The wavelength inside the plasmon resonance range increased photoluminescence by nearly four times when compared to the photoluminescence outside the range. The resonant wavelength of the quantum dots linked with gold, stimulates a collective oscillation of the material’s conductive electrons leading to strong absorption of light, which increases photoluminescence when compared to the quantum dots that are not linked with gold.
The research conducted at the Center for Functional Nanomaterials in Brookhaven Lab was done by Mircea Cotlet, Mathew Maye and Oleg Gang.
Source: http://www.bnl.gov/