Polaritons Convert Light To Electrical Charge

Researchers have developed a new type of high-efficiency photodetector. The concept comes from the photosynthetic complexes plants use to turn sunlight into energy. The researchers used unique quasiparticles known as polaritons. The new detector generates the particles in an organic thin film.

Photodetectors are used in cameras, optical communication systems, and many other applications to turn photons into electrical signals. The devices combine long-range transport of optical energy with long-range conversion to electrical current. The new arrangement could enhance the power generation efficiency of solar cells greatly.

Polaritons combine molecular excited states with photons, giving them light-like and matter-like properties that allow long-range energy transport and conversion. The photodetector is one of the first practical optoelectronic devices based on quasiparticles.

The researchers designed structures that allow polariton propagation over long distances in an organic semiconductor thin film. They also figured out how to integrate a simple organic detector into the propagation region to produce efficient polariton-to-charge conversion.

The new photodetector converts light to electrical current more efficiently than a comparable silicon photodiode.

The new work revealed important insights into how polaritons propagate in open structures with a single mirror. The new device also allowed the first measurements of efficient incident photons to polaritons conversion.

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