Fabrication of opaque aluminum electrode-based perovskite solar cells enabled by the interface optimization

摘要

In the total cost of perovskite solar cells (PVSK), the most successfully used indium-tin-oxide (ITO) transparent electrode takes up a substantial amount, which could be big limit for the commercialization of PVSK cells. Aluminum (Al) foil is an extremely low-cost metal electrode with high conductivity and is an ideal alternative for the ITO electrode in PVSKs. Aiming to develop low-cost PVSK, we systematically optimized the layer sequential of inverted PVSK based on the opaque Al bottom electrode. The unsuitable work functions of Al electrode and the poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA) hole transport layer lead to low device performance. Through the introduction of a thin molybdenum (VI) oxide (MoO3) layer between the Al electrode and PTAA layer, the hole injection barrier was minimized, leading to a dramatic improvement of device performance. By adjusting the thicknesses of the MoO3 interlayer, a champion cell showed a power conversion efficiency of 7.09% based on spray-coated silver nanowires top electrode, proving the concept of using aluminum foil in making lowcost perovskite solar cells.

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