MOFs for Cheaper White LEDs

3D MOF structure composed of an AAA arrangement, where A represents the 2D sheet along the ab-axis. The ligand forms a bridge between two metallic layers to form a 2D network (Source: ACS)

3D MOF structure for LED composed of an AAA arrangement, where A represents the 2D sheet along the ab-axis. The ligand forms a bridge between two metallic layers to form a 2D network (Source: ACS)

Replacing tradi­tional light bulbs with light-emitting diodes could take a significant bite out of global energy consumption. But making white LEDs isn’t com­pletely benign or budget friendly. To help reduce the environ­mental footprint and cost of these lights, researchers have developed the first white LED with a hybrid, metal-organic framework material.

Wide­spread use of low-power, long-lasting LEDs in the U.S. could save nearly 348 terawatt-hours by 2027, which equals the annual output of 44 power plants, according to the U.S. Depart­ment of Energy. But white LEDs are currently made with rare-earth elements, and mining these minerals can be costly and produce toxic waste. Addi­tionally, existing commer­cial methods for producing white LEDs involve multiple components and steps that reduce effi­ciency and quality.

So, Kuang-Lieh Lu, Yang-Fang Chen and colleagues developed more cost-ef­fective and environ­mentally friendly white LEDs using graphene and a stron­tium-based, metal-organic frame­work (MOF) that does not include rare-earth elements. MOFs comprise a pro­mising new class of hybrid materials made of metallic ions and organic ligands. Testing showed that the devices’ emission spectrum was close to that of natural sunlight. (Source: ACS)

Reference: G. Haider et al.: Electrically Driven White Light Emission from Intrinsic Metal–Organic Framework, ACS Nano, online 31 August 2016; DOI: 10.1021/acsnano.6b03030

Link: Dept. of Physics, National Taiwan University, Taipei, Taiwan

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