Thermally Stable Perovskite Solar Cells by All-Vacuum Deposition

Vacuum deposition is a solvent-free method suitable for growing thin films of metal halide perovskite (MHP) semiconductors. However, most reports of high-efficiency solar cells based on such vacuum-deposited MHP films incorporate solution-processed hole transport layers (HTLs), thereby complicating prospects of industrial upscaling and potentially affecting the overall device stability. In this work, we investigate organometallic copper phthalocyanine (CuPc) and zinc phthalocyanine (ZnPc) as alternative, low-cost, and durable HTLs in all-vacuum-deposited solvent-free formamidinium-cesium lead triodide [CH(NH2)2]0.83Cs0.17PbI3 (FACsPbI3) perovskite solar cells. We elucidate that the CuPc HTL, when employed in an inverted p-i-n solar cell configuration, attains a solar-to-electrical power conversion efficiency of up to 13.9%. Importantly, unencapsulated devices as large as 1 cm2 exhibited excellent longterm stability, demonstrating no observable degradation in efficiency after more than 5000 h in storage and 3700 h under 85 degrees C thermal stressing in N2 atmosphere.

Automated summary

This study investigates the use of CuPc and ZnPc as alternative hole transport layers (HTLs) in all-vacuum-deposited metal halide perovskite (MHP) solar cells. The CuPc HTL achieves a solar-to-electrical power conversion efficiency of up to 13.9% and demonstrates excellent long-term stability, with no observable degradation even after 5000 hours in storage and 3700 hours under thermal stress.