6 - Quantum dot materials, devices, and their applications in photomedicine

Abstract

Quantum dot (QD) materials are highly attractive as platforms for multimodal applications and the development of wearable optoelectronic devices for medical applications. QDs are semiconductor nanocrystals with a size-tunable emission wavelength, high photoluminescence quantum yield, wide absorption bandwidth, narrow emission bandwidth linked to narrow particle size distribution, and photostability. These unique optical properties have encouraged new applications. QD light-emitting diodes (QLEDs) are attracting the most attention for applications in health care. QLEDs’ capability for flexible form factors, with simultaneous high-power density and narrow emission bandwidth at clinically relevant deep red wavelengths, makes them strong candidate light sources for photomedicine. This chapter explores the fundamentals of QD materials, QD devices, and phototherapeutic applications, including their properties, synthesis, evolution, and operating principles of QLEDs. QD-proposed light-based theranostic applications are summarized. The development and photomedical applications of devices, especially QLEDs for photobiomodulation (PBM) and photodynamic therapy (PDT), are described. Recent advances in red-emitting QLEDs and an explanation of relevant radiometric parameters for phototherapy and their evaluation as efficient photomedical light sources are discussed. The unique features and advantages of flexible QLEDs as alternative photomedical light sources and results of in vitro studies in PDT and PBM are presented and compared to results using organic light-emitting diodes. The future of QLEDs, designs for QLED-based medical devices, and examples of devices for health monitoring and diagnostics are presented.