Light extraction film for organic light-emitting diodes based on an eco-friendly template comprising cellulose and polyphenon 60

The demand for eco-friendly, alternative materials and processes is increasing across various industries to substitute petroleum-based materials, which have negative environmental impacts. Therefore, this study developed an environmentally sustainable template using polyphenon 60 (P60) extracted from green tea and hydroxyethyl cellulose (HEC) via a solvent-free process employing only deionized water. The template surface exhibited randomly distributed microscale aggregates owing to the chemical interactions between HEC and P60, with their morphology varying as a function of the P60 concentration. The quantitative analysis utilizing fill factor calculations demonstrated that increased P60 concentration led to a higher aggregate density and larger structure sizes as the fill factor values increased from 21% at 1.5 wt% to 45% at 2.0 wt% and 86% at 2.5 wt%. This precise modulation of the P60 concentration enabled systematic control over the aggregate size and density, offering a significant advantage in optimizing the structural properties of the enhanced optical performance template. The light extraction film showed enhanced efficiency of up to 29.5% in all directions when integrated into an organic light-emitting diode (OLED), validating the effectiveness of the proposed method in improving device performance. These findings highlight a scalable and sustainable approach for advancing OLED display and lighting technologies.