Efficient broadband conversion via quantum dots with built-in charge

A. Sergeev, K. Sablon, N. Vagidov, J. Little, V. Mitin
University at Buffalo, US

Keywords: quantum dots with built-in charge, broadband conversion, carrier lifetime

Summary:

Recently proposed by ARL – University at Buffalo team, the Q-BIC technology is a promising basis for developing high-efficiency, broadband (all-weather), rugged, light-weight, scalable, and relatively inexpensive single-junction solar cells capable of converting of 35 - 50% of solar energy into electric power. First set of photovoltaic devices based on Q-BIC structures with random positions of quantum dots (QD) has demonstrated that the charging of QDs up to six electrons per dot increases the short-circuit current by 9 mA/cm2 without degradation of the open-circuit voltage. Studying spectral characteristics of the photoresponse, we have also shown that the harvesting and conversion of the sub-bandgap IR radiation gives additional 5% to the photovoltaic efficiency. Moreover, the IR conversion via QDs is significantly enhanced by the short-wavelength radiation due to strong inter-electron interaction in QD structures. This effect makes Q-BIC structures especially attractive for concentrating photovoltaics. Next step optimization of Q-BIC PV devices is in progress.