Charge Tunneling and Exciton Dissociation in Photochromic Molecule Bridged Quantum Dot Systems*

The inherent limitations of electronic based computational systems has motivated many to pursue the development of alternative optical based computing. To achieve functional, high performance photonic devices an optical analog to a transistor (an optical switch) must be developed. In this work, we report a novel material system which exhibits strong, reversible, and tunable optical switching effects. Our system is composed of lead sulfide quatum dots (QDs) bridged with photochromic molecules (PCMs). By modulating the potetial barrier between the QD and PCM through optically induced chemical configuration change of the PCM, we observe dramatic changes in the photoluminescence (PL) and the excitonic lifetime. The implications of our findings in optical computing and memory devices will be discussed.