The next generation of HD

An international research team is paving the way for brighter, lighter and more energy-efficient TVs and smart devices, thanks to a new process that could lead to a new generation of high definition (HD).

The researchers from the UK, Switzerland, the USA and Taiwan recently revealed that when quantum dots — tiny flecks of semiconductor that are prized for their crisp colours — are clustered together they are more fluorescent, providing a wide variety of colours. Their work has been published in the journal Science Advances.

Through the project, quantum dots containing methylammonium lead bromine (MAPbBr₃) were created. The experts found that by creating lamellar structures — fine layers alternating between different materials — the human eye’s response to the visible light was very high. This means that the material re-emitted a lot of the light that it absorbed and very bright colours were created. The team have named this process aggregation-induced emission.

“Normally the quantum yield, which determines the brightness, degrades significantly as quantum dots aggregate, forming crystalline solids,” explained Professor Chih-Jen Shih, who created the quantum dots and led the investigation at ETH Zurich, Switzerland. “However, our investigations show that brighter levels are achievable because of the new photonic process that we have discovered and have named aggregation-induced emission (AIE).”

“This AIE process can revolutionise the quality of the colours in TVs because the base colours are red, blue and green,” said Dr Elton Santos, who led the UK research team at Queen’s University Belfast. “Using AIE, we can create the brightest green colour ever achieved by any nanomaterial.

“Once this bright green is integrated with the other two colours, the number of new colour combinations could exceed what is currently possible. The latest QD technology, which is just about to be released to market, allows for one billion colours, which is 64 times more than the average TV. However, using the process we have discovered, we can actually make this even better.”

Professor Shangchao Lin, who led the research at Florida State University, USA, added: “Our findings also show that the perovskite nanocrystals emit light extremely quickly and are very energy efficient. This means reduction of electricity consumption and consistent colour expression throughout a long lifespan.”

According to Dr Santos, the researchers anticipate that the number of colours a display can present could be increased by more than 50%, resulting in a new type of ‘high definition’. The team are now looking for similar processes for blue and red colours, so they can create a screen display that replicates all the colours that can be captured by the human eye.

Professor Shih said the research is almost ready for commercialisation, noting, “The remaining tasks will be to enhance the stability of these compounds and to ensure that they can endure high temperatures, humidity and electrical energy being applied.”

Dr Santos is similarly confident, claiming that “the next HD generation is just as close as three to four years away”.

Image caption: The LED device yields pure green emission pumped by blue GaN LED chips.