Reusable Fully Sputtered Architecture for Semitransparent Perovskite Solar Cells Integrating CsPbI3

Semitransparency is essential for applications in agrivoltaics and building-integrated photovoltaics. Here, semitransparent perovskite solar cells (PSC) are developed using high-vacuum sputtering deposition of advanced oxide layers. The bottom electrode is a Gig-Lox TiO2 multibranched sponge deposited on commercial c-TiO2/FTO by reactive sputtering. This sponge is then infiltrated with δ-CsPbI3, which remains mostly embedded into the TiO2 scaffold during the subsequent deposition steps. On top of this stack, a transparent 7 nm MoOx buffer layer is deposited at low power density in pure Ar from a MoO3 target, followed by the deposition of a 90 nm-thick ITO layer by reactive sputtering in Ar–O2. The resulting device can be described as an HTL-free-like architecture, where the ultrathin MoOx layer enables hole transfer into ITO via defect-assisted tunneling. The perovskite, initially in the nonphotoactive δ-phase, is converted into the photoactive γ-phase upon annealing the full FTO/c-TiO2/Gig-Lox TiO2/CsPbI3/MoOx/ITO stack at 350 °C. Full device annealing is enabled by the inorganic nature of the entire stack, and reannealing is also feasible at the same temperature for reuse. Simulations and experiments suggest that an interplay between the Gig-Lox TiO2 thickness and the MoOx interlayer modulates both transmittance and PSC efficiency by tuning the CsPbI3 Fermi level and the CsPbI3/MoOx interface dipole. The proposed reusable, fully sputtered semitransparent PSC architecture integrating CsPbI3 opens applicative perspectives in building-integrated photovoltaics and agrivoltaics.