Room Temperature Operation of a Quantum Ratchet Intermediate Band Solar Cell

An intermediate band solar cell which generates photocurrent due to sequential absorption of two sub-bandgap photons at temperatures up 300 K was realized. The is comprised a “quantum ratchet” semiconductor nanostructure designed store the photoelectron in long-lived state that allows for efficient optical re-absorption; it incorporates potential barrier both increase confinement electrons and reduce thermal escape. This leads extended electron lifetimes ratchet room temperature operation. At low (≈12 K), exhibit lifetime τRB > 100 s, representing an by factor ≈107 over device without barrier.