Efficiency Improvement in a Powder‐Based Flexible Electroluminescence Device using Ag Nanothin‐Film‐Coated Transparent Electrodes

• Published in: Advanced photonics research Vol. 4; no. 6
• Main Authors: Yun, Sanghun, Lee, Soo-Keun, Allabergenov, Bunyod, Park, Jong Chun, Moon, SoYeon, Lee, Seong Eui, Choi, Byeongdae
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley & Sons, Inc 01-06-2023; Wiley-VCH
• Subjects: Ag nanothin film; Ag transparent electrode; color shift; Dielectric properties; Efficiency; EL film display; Electrodes; Light; Lighting; Optimization; Polyethylene terephthalate; powder-based electroluminescent devices; Thin films
• ISSN: 2699-9293; 2699-9293
• DOI: 10.1002/adpr.202200291

Powder‐based electroluminescent (EL) devices have attracted attention as a technology for realizing flexible curved lighting or displays. However, low efficiency is a challenge to overcome practical applications. Herein, the characteristics of EL devices are analyzed according to the properties of an indium‐tin‐oxide (ITO) electrode, and EL devices containing a Ag nanothin‐film for efficiency enhancement are reported. As the emission area of the as‐prepared EL device decreases, the power loss per unit area increases, resulting in a low device efficiency. To decrease the power loss of the device, a several‐nano meter‐thick Ag thin film is formed over a polyethylene terephthalate film to obtain 88% transmittance and 10 Ω sq−1 sheet resistance. An EL paste is printed thereon, followed by upper electrode film stacking to fabricate an EL device with a sandwich structure. Compared to an ITO film‐based device with 40 Ω sq−1 sheet resistance, the as‐prepared EL film device consumes less power and exhibits ≈12% higher device efficiency. The possibility of powder‐based EL film display by playing pattern images on 9 × 9 pixel arrays formed on Ag nanothin‐film electrodes is confirmed. It is believed that the present results promote practical research on future devices, including stretchable and bendable EL displays.
Ag electrodes have superior ductility and excellent flexibility compared to indium‐tin‐oxide electrode. The resistivity is also low; therefore, power loss and signal delay may be reduced when the display is driven, and thus an image without distortion may be displayed. The picture shows efficiency improvement and pattern image of an electroluminescent film display using the Ag nanothin film electrode.