Quantum dot IR photodetectors and solar cells enhanced by built-in charge

Electron transitions in the IR range, which correspond to transitions in the narrow bandgap semiconductors, are also realized in quantum-dot structures. Quantum-dot optoelectronic devices, which can replace devices based on narrow bandgap semiconductors, provide more flexibility for nanoscale engineering of photoelectron kinetics as well as improving coupling to IR radiation. Here, we report on radical improvement of quantum-dot solar cells and quantum-dot infrared photodetectors provided by Quantum dots with Built-In Charge (Q-BIC). We observed a 50% increase in the photovoltaic efficiency of n-doped Q-BIC solar cells with ∼ 6 electrons per dot. In this cell, the short circuit current density increases up to 24.30mA/cm ², compared with 15.07mA/cm ² in an undoped cell, without deterioration of the open circuit voltage. We also observed ∼25 times increase of the photoresponse of Q-BIC IR photodetector when the built-in charge increases from 1 electron to 6 electrons per dot.