Sputtered Transport Layers Enabling Ambient-Air Processed CsPbI 3 Perovskite Solar Cells

Abstract

Perovskite solar cells offer promising efficiency compared to traditional technologies. In this study, NiO x and ZnO were employed as charge transport layers using a magnetron sputtering process within a p-i-n architecture (ITO/NiO x /CsPbI 3 /ZnO/Au). This approach produced uniform, low-defect interfaces and supports low-temperature, scalable fabrication suitable for flexible substrates. Our investigation, using techniques such as X-Ray Diffraction (XRD), UV-Visible spectroscopy, Scanning Electron Microscopy (SEM), and Atomic Force Microscope (AFM), revealed the formation of uniform layers deposited by the magnetron sputtering process. The photoactive CsPbI 3 layer was deposited via a spin coating solution process. UV-Visible spectroscopy revealed strong absorbance in the wavelength range of 400 - 750 nm, corresponding to a band gap of 1.67 eV. XRD analysis confirmed the crystalline structure of both transport and active layers. Surface morphology studies revealed that CsPbI 3 formed large grains with good coverage, which contributed to improved device performance. AFM analysis revealed uniform surface coverage with low surface roughness values of 0.7 nm and 3.4 nm for NiO x and ZnO, respectively. The best-performing device achieved a power conversion efficiency of 7.8%, with an open-circuit voltage of 0.82 V, a short-circuit current density of 14.25 mA/cm 2 , and a fill factor of 67%. These results demonstrate the potential of combining sputter-deposited transport layers with solution-processed perovskites for efficient, scalable photovoltaic devices.