Flexible Multicolor Electroluminescent Devices on Cellulose Nanocrystal Platform

In this work, flexible electroluminescent devices (FELDs) are demonstrated using environmentally-friendly cellulose nanocrystal (CNC) substrates with a silver nanowire conductive network. The CNC sheets with drop-casted silver nanowires act as highly transparent conductive electrodes for an electroluminescent layer (a phosphorescent ink containing Cu/Br-doped ZnS microparticles). This phosphorescent device requires operating voltages as low as 7 V and achieves high luminance of up to 43 Cd m(-2) (at 50 V). Furthermore, through impregnating the CNC host material with Rhodamine 6G or Thiazol Yellow G, different emission colors are achieved: blue, turquoise, green, and purple light emission having a broad (400-650 nm) luminescence spectrum are obtained. This device, which uses earth-abundant, cost-effective, and recyclable materials, is envisioned to lead to advancements in the areas of electronics and lighting technology.