Transforming Device Efficiency and Stability in NiO-Sputtered n-i-p Perovskite Solar Cells by Soft-Landing and a Thin Spiro-OMeTAD Buffer Layer

[EN] The integration of inorganic materials in perovskite solar cells (PSCs) is critical for enhancing long-term operational stability, scalability, and economic viability. Here, we demonstrate the transformational efficacy of using a modified protocol for sputtered nickel oxide as a hole transport layer (HTL) in n-i-p structured PSCs, in conjunction with a thin Spiro-OMeTAD buffer layer. The introduction of a biased grid and a buffer interface enable us to achieve a soft landing of NiO on the halide perovskite, thereby minimizing process-induced interfacial damage. Our results indicate that the buffer layer serves solely as an interfacial protection layer, rather than as a functional HTL. Using this approach, we report champion power conversion efficiencies of 23.45% (mean approximate to 22.2%) on rigid glass substrates and 22.1% (mean approximate to 21%) on flexible ITO-coated PET substrates, both employing fully inorganic charge transport layers. These results represent unprecedented enhancements over previously reported highest PCE values (<12%) for n-i-p devices using sputtered NiO as the HTL, placing them on par with p-i-n architectures that utilize a combination of NiO and organic HTLs. This work demonstrates a scalable, commercially viable pathway toward high-efficiency, stable perovskite photovoltaics based solely on sputtered inorganic layers, offering a competitive edge for further development.