  Exciton-polaritons are quasiparticles consisting of a linear superposition of
photonic and excitonic states, offering potential for nonlinear optical
devices. The excitonic component of the polariton provides a finite Coulomb
scattering cross section, such that the different types of exciton found in
organic materials (Frenkel) and inorganic materials (Wannier-Mott) produce
polaritons with different interparticle interaction strength. A hybrid
polariton state with distinct excitons provides a potential technological route
towards in-situ control of nonlinear behaviour. Here we demonstrate a device in
which hybrid polaritons are displayed at ambient temperatures, the excitonic
component of which is part Frenkel and part Wannier-Mott, and in which the
dominant exciton type can be switched with an applied voltage. The device
consists of an open microcavity containing both organic dye and a monolayer of
the transition metal dichalcogenide WS$_2$. Our findings offer a perspective
for electrically controlled nonlinear polariton devices at room temperature.
