Long-Range Energy Transfer in Strongly Coupled Donor-Acceptor Phototransistors

Strong light-matter coupling offers a way to tailor the optoelectronic properties of materials. Energy transfer between strongly coupled donor-acceptor pairs shows remarkable efficiency beyond the Förster distance via coupling through a confined photon. This long-range energy transfer is facilitated through the collective nature of polaritonic states. Here, the cooperative, strong coupling of a donor (MoS₂ monolayer) and an acceptor (BRK) generates mixed polaritonic states. The photocurrent spectrum of the MoS₂ monolayer is measured in a field effect transistor while coupling the two oscillators to the confined cavity mode. The strongly coupled system shows efficient energy transfer, which is observed through the photoresponsivity even the donor and acceptor are physically separated by 500 Å. These studies are further correlated with the Hopfield coefficients and the overlap integral of the lower polaritonic and uncoupled/dark states. Cavity detuning and distance-dependent studies support the above evidence. These observations open new avenues for using long-range interaction of polaritonic states in optoelectronic devices.