Transparent Light‐Emitting Electrochemical Cells

Abstract Single layer light‐emitting electrochemical cells (LECs) are amongst the simplest electroluminescent devices and operate with air‐stable electrodes. Transparent light‐emitting devices are of great interest as they can enable new applications in consumer electronics. In this work, a transparent ionic transition metal complex based LEC is fabricated by developing a transparent top contact based on tin (IV) oxide (SnO₂) and indium‐tin oxide, processed by low‐temperature atomic layer deposition and pulsed laser deposition, respectively. The resulting devices present transparency in excess of 75% over the full visible spectrum (380–750 nm), with 82% transmission at the emission peak (563 nm). The devices emit from the front and the rear with high luminance (260 cd m⁻²) and long lifetime (176 h). These parameters place them among the highest performing single layer transparent electroluminescent devices.