Flexible Multicolor Electroluminescent Devices on Cellulose Nanocrystal Platform

Abstract

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.