Nanocrystals could lead to lower-cost digital displays

Engineers have created nanoscale crystals that can produce the red, green and blue laser light needed in digital displays.

At the moment, each colour in digital devices such as Blu-ray DVD players is made with different semiconductor materials and by elaborate crystal growth processes.

The researchers at Brown University and QD Vision believe their technology could open doors to making products such as cheaper, more efficient high-performance digital displays.

‘Today, in order to create a laser display with arbitrary colours, from white to shades of pink or teal, you’d need these three separate material systems to come together in the form of three distinct lasers that in no way, shape or form would have anything in common,’ said Arto Nurmikko, professor of engineering at Brown University.

The materials in the prototype lasers are nanometre-sized semiconductor particles called colloidal quantum dots or nanocrystals with an inner core of cadmium and selenium alloy and a coating of zinc, cadmium and sulphur alloy and a proprietary organic molecular glue.

Chemists at QD Vision in Massachusetts synthesise the nanocrystals using a wet chemistry process that allows them to precisely vary the nanocrystal size by varying the production time.

‘We have managed to show that it’s possible to create not only light, but laser light,’ Nurmikko said. ‘In principle, we now have some benefits: using the same chemistry for all colours, producing lasers in a very inexpensive way, relatively speaking, and the ability to apply them to all kinds of surfaces regardless of shape. That makes possible all kinds of device configurations for the future.’

The US Department of Energy, the Air Force Office for Scientific Research and the National Science Foundation supported the research.