Recent advances in flexible and wearable OLEDs for biomedical applications: a review

Light-based therapies and diagnostics have gained prominence in medicine due to their non-invasive approach and therapeutic efficacy. Among these technologies, organic light-emitting diodes (OLEDs) are emerging as promising platforms in healthcare, offering advantages such as mechanical flexibility, lightweight construction, and efficient surface emission. Initially developed for display applications, OLEDs have been adapted for biomedical use, enabling conformal integration onto the skin or within the body. Here, we present recent advances in OLED technologies for biomedical applications, focusing on the development and optimization of OLEDs to meet the specific requirements of biomedical use. Developments in device platforms-utilizing flexible substrates and free-form architectures-are discussed, enabling the realization of wearable and implantable systems. Applications are categorized based on functional mechanisms of light-based stimulation and sensing, including photobiomodulation (PBM), photodynamic therapy (PDT), optogenetics, and biosensing. Finally, we conclude by outlining key remaining challenges in the development of OLEDs for biomedical applications.