Light management is one of the cornerstones of modern human society, allowing for continuous economic output throughout the 24-hour cycle.
Currently, practically every dominant lighting technology operates through the process of luminescence. Among the luminescent devices, light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs) are the key technologies that provide lighting of today.
However, LEDs and OLEDs utilize materials predominantly sourced from China (e.g. In, Ga, As) or South Africa (e.g. Ir), resulting in supply chains associated with political risks.
Furthermore, the extraction of these minerals commonly is an unsustainable, environment-degrading, and polluting process.
Moreover, OLEDs are costly due to their complex structure [Figure 1 A] and manufacturing process, limiting their application potential in general lighting solutions.
Like OLEDs, light-emitting electrochemical cells (LECs) are luminescent thin-layer lighting devices. Due to the simple LEC architecture [Figure 1 B] and easy-to-scale printing techniques for their fabrication, LECs are poised to become the predominant low-cost lighting solution of the future.
Furthermore, through the exclusive use of organic materials in the light-emitting layer, LECs hold the promise of evolving into the most environmentally friendly and sustainable class of lighting devices on the market. As of yet, LECs have not been commercially adopted as lighting solutions.
THE PROBLEM
OLEDs are devices that require reactive air-sensitive electrode materials[1] and transition metal (e.g. Ir) complexes[2] in their emissive layers.
Hence, the OLED manufacturing process requires a special oxygen-free environment complicating and increasing manufacturing costs. Accordingly, the complex structure together with material, infrastructure, and production costs result in OLEDs being relatively expensive and not suitable for low-cost lighting solutions.
LED lighting technology has achieved popularity for its high energy efficiency and longevity. However, the LED production manufacturing process involves the use of toxic non-metals and rare-earth elements, which are predominantly sourced from China and have detrimental effects on ecosystems and human health.
For example, gallium arsenide is a key component in LEDs that are known to be carcinogenic and highly toxic to various organs including the lung, testes, kidney, brain, and immune system,[3] with no effective treatment available today.
In addition, LEDs contain hazardous substances like lead and other heavy metals, presenting challenges for proper disposal and recycling. It has been demonstrated that LED waste leaks excessive amounts of copper, nickel, silver, and lead ions into the environment,[4] not only resulting in non-compliance with regulations but also releasing toxic substances into the environment, posing a threat to soil and water quality.
Importantly, since LEDs started to achieve market penetration in 2012 and the expected lifetime of these devices is up to 15 years, the next 10 years will result in a substantial increase in LED waste[5] making both the above-discussed issues even more relevant.
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