Physically & Chemically Stable Molybdenum-Based Composite Electrodes for P-I-N Perovskite Solar Cells.

Metal halide perovskite solar cells (PSCs) have garnered much attention in recent years due to their great potential as the next-generation photovoltaics. Despite the remarkable advancements in PSCs utilizing traditional metal electrode like Au, Ag, Cu, challenges such as stability concerns and elevated costs have necessitated the exploration of innovative electrode designs to facilitate industrial commercialization. Herein, we developed a physically & chemically stable molybdenum (Mo) based composite electrode to fundamentally tackle the instability factors introduced by electrodes in PSCs. The combined spatially resolved element analyses and theoretical study demonstrated the high diffusion barrier of metal Mo ion within the entire device. Structural and morphology characterization also revealed the negligible plastic deformation and halide-metal reaction during aging when Mo was in contact with perovskite (PVSK). The electrode/underlayer junction was further stabilized by a thin seed layer of titanium (Ti) to improve Mo film's uniformity and adhesion. Based on a corresponding p-i-n PSCs (ITO/PTAA/PVSK/C 60 /SnO 2 /ITO/Ti/Mo), the champion sample could deliver an efficiency of 22.25%, which was among the highest value for PSCs based on molybdenum electrode. Meanwhile, the device showed negligible performance decay after 2000 hours operation under 1 sun at room temperature, and retained 91% of the initial value after 1300 hours at an elevated temperature of 50-60°C. In summary, the multilayer Mo electrode opened an effective avenue to all-round stable electrode design in high-performance PSCs, while the configuration principle on intrinsically stable electrode equipped with interfacial buffer could further benefit other optoelectronic devices. This article is protected by copyright. All rights reserved.