Interband cascade photovoltaic devices

A photovoltaic (PV) device based on an interband cascade (IC) structure is proposed for efficiently converting solar and thermal energy to electricity. These IC PV devices employ absorption and transport regions with characteristics that are favorable for achieving high open-circuit voltage and thus possibly improving conversion efficiency over conventional PV devices. Preliminary experiments carried out using IC infrared photodetectors (seven stages) and lasers (11 stages) showed open-circuit voltages that exceed the single-band gap voltage from these devices under infrared illumination. The observed open-circuit voltage demonstrates multiple stages operating in series and provides an initial proof of concept for IC PV devices.