Flexible organic light-emitting diodes for antimicrobial photodynamic therapy

Bacterial infection and the growth of antibiotic resistance is a serious problem that leads to patient suffering,death and increased costs of healthcare.To address this problem,we propose using flexible organic light-emitting diodes(OLEDs)as light sources for photodynamic therapy(PDT)to kill bacteria.PDT involves the use of light and a photosensitizer to generate reactive oxygen species that kill neighbouring cells.We have developed flexible top-emitting OLEDs with the ability to tune the emission peak from 669 to 737 nm to match the photosensitizer,together with high irradiance,low driving voltage,long operational lifetime and adequate shelf-life.These features enable OLEDs to be the ideal candidate for ambulatory PDT light sources.A detailed study of OLED–PDT for killing Staphylococcus aureus was performed.The results show that our OLEDs in combination with the photosensitizer methylene blue,can kill more than 99%of bacteria.This indicates a huge potential for using OLEDs to treat bacterial infections.

Organic photovoltaics for simultaneous energy harvesting and high-speed MIMO optical wireless communications

We show that organic photovoltaics(OPVs)are suitable for high-speed optical wireless data receivers that can also harvest power.In addition,these OPVs are of particular interest for indoor applications,as their bandgap is larger than that of silicon,leading to better matching to the spectrum of artificial light.By selecting a suitable combination of a narrow bandgap donor polymer and a nonfullerene acceptor,stable OPVs are fabricated with a power conversion efficiency of 8.8%under 1 Sun and 14%under indoor lighting conditions.In an optical wireless communication experiment,a data rate of 363 Mb/s and a simultaneous harvested power of 10.9 mW are achieved in a 4-by-4 multipleinput multiple-output(MIMO)setup that consists of four laser diodes,each transmitting 56 mW optical power and four OPV cells on a single panel as receivers at a distance of 40 cm.This result is the highest reported data rate using OPVs as data receivers and energy harvesters.This finding may be relevant to future mobile communication applications because it enables enhanced wireless data communication performance while prolonging the battery life in a mobile device.

A hybrid organic-inorganic polariton LED

Polaritons are quasi-particles composed of a superposition of excitons and photons that can be created within a strongly coupled optical microcavity.Here,we describe a structure in which a strongly coupled microcavity containing an organic semiconductor is coupled to a second microcavity containing a series of weakly coupled inorganic quantum wells.We show that optical hybridisation occurs between the optical modes of the two cavities,creating a delocalised polaritonic state.By electrically injecting electron–hole pairs into the inorganic quantum-well system,we are able to transfer energy between the cavities and populate organic-exciton polaritons.Our approach represents a new strategy to create highly efficient devices for emerging‘polaritonic’technologies.