Light therapy, a treatment originating from ancient times, began to be applied in various modern medical fields in the 19th century. Recently, its scope of application has actively expanded to fields such as promoting wound healing and skin care. Furthermore, it is garnering significant attention as reports suggest its potential in preventing cancer, intractable skin diseases, and even dementia and mild cognitive impairment (MCI).

For a long time, medical light source devices have primarily developed based on point-source LED technology, which, however, possesses inherent technical limitations. In contrast, OLEDs, with their advantages of being a uniform area source, flexibility, and low heat generation, represent the most suitable technology for next-generation medical light sources.

Our research focuses on the development of ultrathin, ultra-flexible, and reliable OLEDs for wound healing applications. Furthermore, we are dedicated to creating more effective next-generation biomedical devices by integrating these OLEDs with plasma patches to enhance their photodynamic therapy (PDT) effects.

Quantum Dot Light-Emitting Diodes (QLEDs) have garnered significant attention as a promising technology for next-generation displays and wearable applications. However, conventional QLEDs possess inherent technical challenges, primarily their high susceptibility to moisture and oxygen and the limitations of rigid encapsulation in flexible environments. In contrast, advanced multilayer barrier systems that are compatible with low-temperature processing represent the most suitable strategy for realizing high-performance, flexible QLED platforms.

Our research focuses on enhancing the reliability and manufacturability of QLEDs through the development of Parylene/Al₂O₃ and TiO₂ nanolaminate structures. By creating highly dense, defect-suppressed dyads, we aim to effectively block degradation pathways such as dark-spot formation. Furthermore, we are dedicated to fabricating patch-type QLEDs that integrate these encapsulation layers, thereby achieving stable emission and superior mechanical flexibility for practical wearable devices.

Perovskite is an advanced optoelectronic material known for its exceptional light absorption and efficient charge transport, enabling high performance even with ultrathin films. Despite these advantages, perovskites suffer from inherent instability when exposed to moisture, oxygen, heat, and ultraviolet light.

Their crystal structure is highly sensitive to environmental fluctuations, and chemical reactions at interfaces—particularly with organic charge-transport layers—can accelerate degradation. As a result, perovskite devices can quickly lose efficiency and structural integrity under real-world conditions.

To ensure long-term operational stability, encapsulation is essential. Encapsulation protects the device by blocking moisture and oxygen, mitigating thermal and photochemical stress, and preserving the electrical and structural properties of the perovskite layer over time. Therefore, it is considered a critical technology for the commercialization of perovskite solar cells.

The dielectric–metal–dielectric (DMD) structure is a multilayer transparent electrode designed to simultaneously achieve high optical transparency and low sheet resistance. In conventional single-metal electrodes, optical reflection and absorption increase, while excessively thin metal layers suffer from poor conductivity.

The DMD architecture addresses these limitations by sandwiching an ultrathin metal film between two dielectric layers. The dielectric layers optimize optical interference to enhance transmittance, while the metal layer provides superior electrical conductivity. Additionally, the dielectrics protect the metal from oxidation, reduce surface roughness, and improve mechanical flexibility.

Owing to these advantages, DMD-based transparent electrodes are considered a promising alternative to indium tin oxide (ITO) for applications such as flexible displays, wearable electronics, OLEDs, and photovoltaic devices.