Interface Modification for Energy Levels Alignment and Charge Extraction in CsPbI${}_3$ Perovskite Solar Cells

Abstract

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 CsPbI${}_3$ 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 CsPbI${}_3$ 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.

arXiv comment20 pages, 4 Figures

References in corpus (4)

• The perovskite/transport layer interfaces dominate non-radiative recombination in efficient perovskite solar cells
• The Efficiency Limit of CH3NH3PbI3 Perovskite Solar Cells
• Revealing the doping density in perovskite solar cells and its impact on device performance
• Pitfalls and prospects of optical spectroscopy to characterize perovskite-transport layer interfaces

Cited by in corpus (1)

• Photovoltaic potential of tin perovskites revealed through layer-by-layer investigation of optoelectronic and charge transport properties