Jan 12 2018
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Light-emitting electrochemical cells (LECs) that emit strong light at high efficiency have been developed by researchers from Umeå University and Linköping University in Sweden.
As such, the flexible, thin and light-weight LEC promises improved and future applications within home diagnostics, illumination, signage and healthcare. The results have been featured in Nature Communications.
The LEC is capable of being flexible, thin and light-weight and can be driven to basically any emission color by the low voltage of a battery. It can also be very cost-effective, as it can be created with the help of low-cost printing and coating methods.
Thus far, a problematic and persistent drawback refers to the fact that it has not been possible to obtain powerful brightness at high efficiency from LEC devices. It has actually been questioned on general grounds whether the LEC even has the potential of being simultaneously efficient and bright.
In the present issue of Nature Communications, a team of scientists from Umeå University, Linköping University and the company LunaLEC AB in Sweden establish a path towards solving this problem. Employing a systematic integration of simulations and experiments, they have succeeded in establishing a generic set of design principles, including optimized doping, balanced trap depths, and electrochemically stabile materials. The researchers' approach has made room for LEC devices capable of emitting light with a high brightness of 2,000 cd/m2 at an electron-to-photon efficiency of 27.5%. "As a point of reference, a normal TV operates between 300 to 500 cd/m2, while 2,000 cd/m2 is the typical brightness of an OLED illumination panel. Concerning efficiency, our LEC device is close to that of common fluorescent tubes", says Ludvig Edman, leader of the project and Professor at the department of physics at Umeå University.
What future does one see for LEC components?
"With this performance, the LEC component is now not only offering low costs and highly attractive design advantages, but is also becoming a true competitor with existing technologies, such as the fluorescent tube, LED and OLED, as regards to efficient and practical operation", says Martijn Kemerink, Professor at the department of physics, chemistry and biology at Linköping University.