Scaling perovskite photovoltaics from lab cells to reliable, large area devices hinges on solvent-free, high-throughput, and compositionally precise film formation. Spin-coated absorbers (central to many record efficiencies) are difficult to industrialise and typically rely on hazardous solvents; conversely, multisource co-evaporation is solvent-free but complex, throughput-limited, and sensitive to cross-contamination. Spin-coated absorbers (central to many record efficiencies) are difficult to industrialise and typically rely on hazardous solvents; conversely, multisource co-evaporation is solvent-free but complex, throughput-limited, and sensitive to cross-contamination. The growth of perovskite films using vapor-phase techniques is therefore emerging as a practical commercial pathway because it offers uniformity, conformality on textured surfaces, and precise control over composition and interfaces [1,2]. Within this context, we introduce a one-step chemical vapor deposition (CVD) route that converts lead precursors directly into metal halide perovskites, offering a simplified, scalable alternative to solution and co-evaporation routes [1].

Our low-vacuum, multiparameter CVD platform reacts methylammonium vapour with either PbI₂ seed layers or ultrathin metallic Pb to form phase-pure with either PbI₂ seed layers or ultrathin metallic Pb to form phase pure MAPbI₃ thin films. The reactor architecture enables control of partial pressures and temperature gradients to promote rapid halide transport and interfacial reaction while remaining fully solvent free. Starting from PbI₂, we obtain highly uniform MAPbI₃ across large areas; X-ray diffraction (XRD) shows attenuation of PbI₂ reflections with concomitant emergence of perovskite peaks, confirming complete conversion. UV–vis data demonstrate tunability of the optical bandgap via mixed PbI₂–PbBr₂ precursors and separate MABr / MAI sublimation sources, providing a straightforward route to higher bandgap absorbers for tandems. Critically, we also convert metallic Pb directly to perovskite: a continuous ~20 nm Pb layer evolves, after MAI exposure, into a compact crystalline perovskite, with serial XRD across successive CVD cycles revealing a mechanistic Pb → PbI₂ → MAPbI₃ sequence. Together, SEM/XRD/optical datasets establish uniform, phase pure films from either PbI₂ or Pb precursors via a single, scalable vapor-phase operation.

From a manufacturing perspective, the one‑step Pb‑to‑perovskite CVD process eliminates toxic solvents, reduces material wastage and tool complexity relative to co‑evaporation, and supports bandgap tailoring (Br/I mixing) and conformal coating on textured Si; key for monolithic perovskite‑on‑silicon tandems and robust single‑junction modules. Ongoing work extends the process to larger substrates and benchmarks device performance, conformality and phase purity under ambient/operational stress, aligning with recent community progress on vapor‑phase scale‑up and process control [1,2].

This program builds on our group’s contributions to perovskite materials chemistry and device physics. In this study, we earlier observed film delamination (likely arising from macro film strain). Tthe next phase to improve optoelectronic performance will be attempting to link microstructural strain to non‑radiative losses and defect formation, providing a framework for defining the CVD process window, defect management and ultimately stability testing [3].

This talk will focus on: (i) the reactor concept and process window for one‑step Pb‑to‑perovskite conversion; (ii) comparative pathways from PbI₂ versus metallic Pb seeds and the kinetic evolution captured by SEM/XRD/UV–vis across CVD cycles; (iii) uniformity maps and phase‑purity metrics at scale; (iv) bandgap tuning via mixed‑halide precursors for single‑junction and tandem targets; and (v) manufacturability benefits including solvent‑free operation, waste minimisation, and conformality relative to other established and reported deposition processes.