Organic Photodiodes with an Extended Responsivity Using Ultrastrong Light–Matter Coupling

In organic photodiodes (OPDs) light is absorbed by excitons, which dissociate\nto generate photocurrent. Here, we demonstrate a novel type of OPD in which\nlight is absorbed by polaritons, hybrid light-matter states. We demonstrate\npolariton OPDs operating in the ultra-strong coupling regime at visible and\ninfrared wavelengths. These devices can be engineered to show narrow\nresponsivity with a very weak angle-dependence. More importantly, they can be\ntuned to operate in a spectral range outside that of the bare exciton\nabsorption. Remarkably, we show that the responsivity of a polariton OPD can be\npushed to near infrared wavelengths, where few organic absorbers are available,\nwith external quantum efficiencies exceeding those of a control OPD.\n