Quantum dot light-emitting diodes as light sources in photomedicine: photodynamic therapy and photobiomodulation

Widespread clinical adoption of photodynamic therapy (PDT) and photobiomodulation (PBM) has been limited due to the lack of a suitable commercial light source. Cost-effective quantum dot light-emitting diodes (QLEDs) promise to be an ideal light source nicely fitting into this niche, not only complying with desired form factors-flexibility, lightweight, and uniform large area illumination-but with narrow emission spectrum and high power density at clinically relevant deep red wavelengths. This paper is intended to provide a review on the development of QLEDs as a photomedical light source, specifically, for PDT and PBM. First, we introduce the potential of QLEDs as light sources in the photomedical field, briefly describe the mechanisms and benefits of both PDT and PBM phototherapies, and present the unique features of flexible QLEDs (FQLEDs) over conventional and commercial light sources. Then, the pioneering work and state-of-the-art research using QLEDs and organic light emitting diodes (OLEDs) for photomedicine are presented. The performance of QLEDs/OLEDs used in photomedical studies and latest progress on QLEDs are also summarized. Ultimately, we discuss the materials and design strategies for fabrication of efficient and stable FQLEDs, and present the basic requirements for near future introduction of FQLEDs into the healthcare and photomedicine markets. This review is expected to be comprehensive and useful to the scientific community interested in developing lightweight and flexible light sources for photomedicine and/or exploring novel applications for OLED/QLED based lighting devices.