Ultra‑transparent and multifunctional IZVO mesh electrodes for next‑generation flexible optoelectronics

Flexible and transparent electronics are revolutionizing the way we think about wearable devices, smart displays, and neuromorphic computing systems. Yet, the search for a highly transparent, conductive, and mechanically resilient electrode material remains a key obstacle to widespread adoption. Now, researchers at Korea University, led by Professor Tae Geun Kim, have engineered a vanadium-doped indium zinc oxide (mIZVO) mesh electrode that offers exceptional performance across optical, electrical, and mechanical domains—opening up promising pathways for next-generation flexible optoelectronic devices.

Using a cost-effective and environmentally friendly fabrication method based on a self-cracking egg white template, the team successfully developed a highly porous amorphous metal oxide network. The mesh structure of mIZVO achieves an outstanding optical transmittance of 97.39% at 550 nm and a low sheet resistance of just 21.24 Ω sq^-1. Unlike traditional brittle ITO electrodes, mIZVO exhibits superb mechanical stability, with only a 630% resistance change after 2000 bending cycles at a 2 mm curvature—making it highly suited for foldable or wearable applications.

A key innovation lies in the deliberate doping of vanadium, which enhances the electrode’s work function (measured at 5.16 eV) and improves charge injection at interfaces. Spectroscopic and microscopic analyses—including XPS, UPS, and TEM—confirm that the amorphous, mesh-like morphology allows for uniform charge transport and minimized stress concentration, enabling both electrical and structural durability under dynamic deformation.

To validate its multifunctional potential, the team integrated the mIZVO electrode into three types of flexible optoelectronic devices. First, organic solar cells (OSCs) utilizing mIZVO achieved a power conversion efficiency (PCE) of 14.38%, outperforming those with conventional ITO or IZO electrodes. This performance is attributed to the improved energy alignment between the electrode and the hole transport layer, as well as increased light transmittance and reduced series resistance.

Second, mIZVO-based organic light-emitting diodes (OLEDs) demonstrated excellent electroluminescent stability and high external quantum efficiency (EQE) of 18.06%. The device also maintained a low turn-on voltage and showed consistent emission at 485 nm, confirming effective hole injection and efficient radiative recombination.

Third, and perhaps most strikingly, the team fabricated flexible, transparent memristor devices using the same mIZVO electrode. These memristors successfully mimicked biological synaptic behavior, including long-term potentiation and depression, while retaining optical transparency and stable mechanical performance. This highlights the electrode’s potential in neuromorphic computing and intelligent wearable systems.

The mIZVO electrode combines scalability, transparency, conductivity, and durability—properties rarely achieved together in a single platform. Moreover, the fabrication approach is compatible with roll-to-roll processing, offering a route toward large-scale, low-cost manufacturing.

With global industries increasingly focusing on lightweight, bendable, and multifunctional electronics, this breakthrough in transparent conductive materials represents a timely and impactful advancement. The Korea University team’s work demonstrates how structural design, material chemistry, and device engineering can converge to deliver real-world solutions, potentially transforming how future electronics are powered, displayed, and interfaced with the human body.