Elucidation of Quantum-Well-Specific Carrier Mobilities in Layered Perovskites

Abstract

Layered organohalide perovskite films consist of quantum wells with concentration distributions tailored to enhance long-range charge transport. Whereas cascaded energy and charge funneling behaviors have been detected with conventional optical spectroscopies, it is not clear that such dynamics contribute to the efficiencies of photovoltaic cells. In this Letter, we use nonlinear photocurrent spectroscopy to selectively target charge transport processes within devices based on layered perovskite quantum wells. The photocurrent induced by a pair of laser pulses is directly measured in this “action” spectroscopy to remove ambiguities in signal interpretation. By varying the external bias, we determine carrier mobilities for quantum-well-specific trajectories taken through the active layers of the devices. The results suggest that the largest quantum wells are primarily responsible for photocurrent production, whereas the smallest quantum wells trap charge carriers and are a major source of energy loss in photovoltaic cells.

Citation

Elucidation of Quantum-Well-Specific Carrier Mobilities in Layered Perovskites
Ninghao Zhou, Zhenyu Ouyang, Liang Yan, Meredith G. McNamee, Wei You, and Andrew M. Moran
The Journal of Physical Chemistry Letters 2021 12 (4), 1116-1123
DOI: 10.1021/acs.jpclett.0c03596