In perovskite solar cells (PSCs) energy levels alignment and charge extraction at the interfaces are the essential factors directly affecting the device performance. In this work, we present a modified interface between all-inorganic CsPbI3 perovskite and its hole selective contact (Spiro-OMeTAD), realized by a dipole molecule trioctylphosphine oxide (TOPO), to align the energy levels. On a passivated perovskite film, by n-Octyl ammonium Iodide (OAI), we created an upward surface band-bending at the interface by TOPO treatment. This improved interface by the dipole molecule induces a better energy level alignment and enhances the charge extraction of holes from the perovskite layer to the hole transport material. Consequently, a Voc of 1.2 V and high-power conversion efficiency (PCE) of over 19% were achieved for inorganic CsPbI3 perovskite solar cells. Further, to demonstrate the effect of the TOPO dipole molecule, we present a layer-by-layer charge extraction study by transient surface photovoltage technique (trSPV) accomplished by charge transport simulation.
@article{arxiv.2307.13174,
title = {Interface Modification for Energy Levels Alignment and Charge Extraction in CsPbI$_3$ Perovskite Solar Cells},
author = {Zafar Iqbal and Fengshuo Zu and Artem Musiienko and Emilio Gutierrez Partida and Hans Kobler and Thomas W. Gries and Gennaro V. Sannino and Laura Canil and Norbert Koch and Martin Stolterfoht and Dieter Neher and Michele Pavone and Ana Belen Munoz-Garcia and Antonio Abate and Qiong Wang},
journal= {arXiv preprint arXiv:2307.13174},
year = {2023}
}