Perovskite is an emerging material for high performance solar cell application with low-cost solution-processable fabrication. As an ink, perovskite composition can be easily modified to create semi-transparent solar cells for window replacement. To enable scalable large-scale production, the spray process is one of the major candidates. In this work, we developed sequential spray deposition (SSD) to create double layer absorbers from different dimensional perovskites. SSD, for the first time, achieves layer-by-layer deposition of different perovskite materials for stacked architecture. To demonstrate the benefits, we spray-coated lower dimension, more stable perovskite onto high performance yet sensitive 3D semi-transparent perovskite. SSD performed under a humid environment (40 - 50% RH) brings about better film stability and retains good performance of 3D perovskite. Sequential spray deposition opens new routes for various stacking designs and large-scale production under economical ambient conditions.

Low dimensional perovskites via DMF : DMSO = 8 : 2 with potential for semi-transparent solar cell led to superior surface morphology with large crystallite size and low defects.

Perovskites have attracted considerable attention for application as high-efficiency photovoltaic devices owing to their low-cost and low-temperature fabrication. A good surface and high crystallinity are necessary for high-performance devices. We examine the negative effects of chemical ambiences on the perovskite crystal formation and morphology. The repeated cation doping (RCD) technique was developed to remedy these issues by gradually dropping methylammonium ions on top of about-to-form perovskite surfaces to cause recrystallization. RCD promotes pinhole-free, compact, and polygonal-like surfaces under various vapor conditions. Furthermore, it enhances the electronic properties and crystallization. The benefits of RCD extend beyond perovskites under vapor ambiences, as it can improve regular and wasted perovskites.

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