Analysis of open-circuit voltage and conversion efficiency in quantum-dot solar cells via detailed-balance-limit theory

Abstract

Via detailed-balance analysis, we systematically studied conversion efficiency limit, short-circuit current, and open-circuit voltage $(V_{oc})$ of quantum dot (QD) solar cells for various absorptivity and bonding energy of QD below host-material absorption band. Our results quantitatively revealed that drops of $V_{oc}$ and conversion efficiency in QD solar cells were caused by the intrinsic consequence of mid-gap absorption band, and that current gain in intermediate-band QD solar cells via multi-step infrared-light absorption must be large enough to compensate at least the intrinsic drop of $V_{oc}$ to improve final conversion efficiency.