The main challenges in the industrial development of the perovskite solar cell (PSC) technology is the upscaling of the deposition of the electro-active layers and the poor stability of PSC devices, which can hinder the path towards commercialization. In this work we will present the transition made in Solliance from lab-scale to a large area fabrication process: first by sheet-to-sheet (S2S) and later by a high-throughput roll-to-roll (R2R) production, using a combination of slot die coating, (spatial) atomic layer deposition (ALD) and sputtering. We will also demonstrate that with the developed S2S deposition processes it is possible to achieve thermal stability at 85°C for 100 cm² PSC modules.

  The S2S perovskite ink formulation and coating/drying process were first optimized in a nip architecture: in this way it was possible to fabricate 144 cm² modules with 13.8% stabilized aperture PCE with no losses with respect to equivalent lab-scale cell of 0.09 cm², an up-scaling of more than three orders of magnitude. For the sake of stability, the same perovskite layer was transferred to a pin stack. Slot die coating was used for the NiO_x hole transport, the perovskite and the PCBM layers, while a combination of (conventional or spatial) ALD and sputtering of ITO were introduced as scalable techniques for the deposition of the semitransparent top electrode. Large area coated non-transparent and semitransparent pin cells with stabilized PCE of up to 17% and 15% respectively were fabricated, with equivalent minimodules of 4 cm² displaying stabilized aperture PCE of 14.3% and 13.6% respectively. Thanks to the introduction of compact metal oxide ETL by ALD and the use of sputtered ITO the semitransparent cells can retain 90% of the initial PCE after 1000h of continuous light soaking or 1000h of thermal stress at 85°C (as much as the lab-scale devices). In addition to this result, a 100 cm² semitransparent module with 12% stabilized aperture PCE will be presented. Remarkably also the 100 cm² module can withstand 1000h of thermal stress at 85°C with only 10% losses.

To further reduce the production cost of PSC, a R2R coating process has been developed in parallel to S2S. An environmentally acceptable solvent was introduced, to avoid using volatile carcinogenic, mutagenic or reprotoxic compounds. By using two R2R coated electro-active layers, 10 cm² and 160 cm² flexible modules with stabilized aperture PCE of 12.3 and 10.1% were demonstrated. In a next step, by applying three consecutive R2R coated electro-active layers, stabilized cell efficiencies up to 16% have been achieved. These R2R deposition processes are now being adapted to a pin architecture to fabricate stable flexible PSCs. The obtained results demonstrate that low-cost, stable, low-temperature and large area manufacturing of perovskite solar modules is within reach by using both S2S and R2R processes.