Fully biocompatible poly(butylene adipate-co-terephthalate) based microstructures for eco-friendly light extraction in organic light-emitting diodes

Organic light-emitting diodes (OLEDs) inherently suffer from severe optical losses, with most generated photons confined by total internal reflection. To mitigate these losses, conventional light-extraction methods rely on complex, energy-intensive fabrication using non-biodegradable materials. Thus, this study presents an eco-friendly and biocompatible strategy that combines poly(butylene adipate- co -terephthalate) (PBAT) as a biodegradable template with carboxymethyl cellulose and tannic acid (ECO-UV) films. Templates and films were fabricated through a simple, low-temperature, solution-based replication process without lithography or vacuum processes, forming irregularly distributed microstructures that enhance light scattering and suppress internal reflection. The OLEDs incorporating the ECO-UV film exhibited up to 36% enhancement in electroluminescence intensity, demonstrating that even a fully biodegradable, solution-processed system can achieve light-extraction performance comparable to that of conventional synthetic counterparts.