The EU-funded PLE project, supported by an ERC Proof of Concept Grant, built on groundbreaking discoveries in the HYPER project about the light-absorbing and emitting properties of perovskite materials. While HYPER led to the development and commercialisation of more efficient solar cells, PLE looked into the light-emitting potential of perovskite nanocrystals to underpin a major advance in solid-state lighting and displays.
‘In HYPER, we were investigating light emission and energy transfer between different semiconductors, looking at how perovskites could function very efficiently as solid absorber layers in solar cells. It was by investigating the properties of metal halide perovskites that we realised they are so luminescent,’ says Henry Snaith, an award-winning Oxford University physicist who led both projects.
Seizing on that discovery, Snaith and his fellow researchers demonstrated in the PLE project how perovskite nanocrystals could function as colour converters, initially for high-colour quality solid-state lighting and subsequently for other light-emitting applications with significant commercial potential.
‘We managed to raise a seed fund of around £800 000 (around EUR 930 370) to launch the company Helio Display Materials, which evolved directly out of the business plan drawn up in PLE,’ Snaith continues. ‘Technically, we have developed much more efficient and more stable light emitters, targeting the specific blue, green and red colour channels. The company is focused on colour converters at present, but the long-term target is perovskite LEDs as the next technology to supersede OLEDs.’
In comparison to current-generation OLED screens, a perovskite LED display would provide cleaner colours and could potentially be much brighter and more energy efficient. Although challenges remain, including improving the stability and longevity of perovskite LEDs and reducing or replacing the use of lead in the nanocrystals to comply with safety standards, Snaith is optimistic about their potential.
‘The research community working on perovskites for light emission is growing at a tremendous pace and the efficiency of perovskite emitters is rising rapidly: perovskite LEDs are already over 20 % efficient, matching OLEDs. It will be exciting to see the progress over the next few years, to witness perovskites surpassing OLEDs in performance,’ he says. ‘These materials could be used in all displays and lighting in the future to create both improved aesthetics and lower energy consumption.’