Organic light-emitting diodes for biomedical applications

Abstract

Organic light-emitting diodes (OLEDs) have been used in displays and lighting applications due to their advantages in material properties, fabrication and device performance. In addition to displays and lighting, OLEDs can also be used as light sources for biomedical applications. Conventional light sources such as lasers, inorganic light-emitting diodes and lamps are widely used in hospitals and clinics. However, they are generally cumbersome and expensive and unsuitable for some biomedical applications requiring compact and cost-effective light sources. OLEDs are thin, lightweight, and can be flexible, which makes them attractive candidates for biomedical applications. The work in this thesis presents the use of OLEDs for biomedical applications such as antimicrobial photodynamic therapy (aPDT) and fluorescence sensing. In aPDT work, OLEDs with different geometries and structures were optimised in terms of spectrum, conductivity, optical power output, lifetime, flexibility and emission uniformity. The effect of aPDT on killing bacteria, parasites and fungi was then evaluated using the optimised OLEDs. In fluorescence sensing work, a compact system based on pulse-driven OLED was developed for sensing dye-labelled DNA as a proof-of-principle study. OLEDs were carefully designed with high optical power output and suitable spectra for achieving high detection sensitivity. An OLED based system for sensing of SARS-CoV-2 antibody was developed. It used an OLED-excited fluorescence-linked immunosorbent assay, and suggests OLEDs are promising for point-of-care testing.