The world’s most efficient light bulb has been created by researchers at Trinity College, Dublin, Ireland, on a minute scale. The bulb comprises a polymer microsphere on which quantum dots have been successfully positioned. This has enhanced the light output of the quantum dots by a factor of 20, and allows the light to be focussed into a fine beam that can be easily manipulated, because the structure is spherical.

The Trinity team coated a polymer microsphere with quantum dots made of the semiconductor cadmium telluride. This caused the microsphere to emit red and green light. Dr John Donegan has been working on improving the efficiency of light emission using quantum dots and creating a tightly focussed beam that could have many applications in areas such as computing, telecommunications and energy production. Creating ‘optical tweezers’ for manipulating DNA is also a major goal for the research team. The beams of light produced are narrow enough to manipulate a single strand of DNA, stretching it and reading the genetic information. Donegan’s group believe that they can go on to create a thinner and more easily manipulated beam of light than ever before.

‘We hope that our microcavity will help in all possible applications of quantum dots, but especially in our ability to manipulate single strands of DNA. It could have major uses in genetic analysis and in gene sequencing where the ability to handle DNA strands with increasing accuracy and dexterity is becoming ever more important,’ said Donegan.