Metal-free glow: New material design cracks sustainable white light for displays
Researchers have created the first white light-emitting device using only metal-free materials, achieving efficient light output without rare metals or complex manufacturing. The breakthrough could lower costs and environmental impact for next-generation displays and lighting—opening new opportunities for manufacturers seeking sustainable alternatives.
Originaltitel: White light-emitting electrochemical cells based on metal-free TADF emitters
<p>The attainment of white emission from a light-emitting electrochemical cell (LEC) is important, since it enables illumination and facile color conversion from devices that can be cost-efficient and sustainable. However, a drawback with current white LECs is that they either employ non-sustainable metals as an emitter constituent or are intrinsically efficiency limited by that the emitter only converts singlet excitons to photons. Organic compounds that emit by thermally activated delayed fluorescence (TADF) can address these issues since they can harvest all excitons for light emission while being metal free. Here, we report on the first white LEC based on solely metal-free TADF emitters, as accomplished through careful tuning of the energy-transfer processes and the electrochemically formed doping structure in the single-layer active material. The designed TADF-LEC emits angle-invariant white light (color rendering index = 88) with an external quantum efficiency of 2.1 % at a luminance of 350 cd/m<sup>2</sup>.</p>