Perovskite solar cells (PSCs) are emerging as a cornerstone in the pursuit of efficient and sustainable solar energy. Their exceptional laboratory-scale performance has sparked considerable interest, yet transitioning these high-efficiency cells to scalable, commercial applications presents a myriad of challenges. Central to these challenges is the reliance on high-toxicity solvents, such as DMF/DMSO for the perovskite layer and Chlorobenzene/ Chloroform for the hole transporting layer (HTL). These substances, while effective in controlled settings, pose significant health and environmental hazards, particularly when considered for large-scale manufacturing. The exposure limits and handling complexities of such chemicals demand urgent attention and alternative solutions.

Moreover, the long-term stability of PSCs under real-world environmental conditions, especially humidity, has been a persistent obstacle. Despite their impressive initial performance, these cells often face degradation over time when exposed to varying humidity levels, questioning their practicality for long-term use. The current production methods and materials, optimized for highly efficient in PSCs, often result in increased production costs, making it challenging to compete with established solar technologies in the market.

In response to these limitations, our study delves into the development of roll-to-roll (R2R) coated perovskite solar cells including the top electrode using low-toxicity solvents, marking a significant shift from traditional methods. This approach not only seeks to reduce the ecological footprint of PSC production but also to enhance the safety and feasibility of large-scale manufacturing. We strategically replaced the conventional solvents with safer alternatives: DI water was used for the tin oxide layer, for the critical perovskite and hole transporting layers, we opted for Acetonitrile (ACN) and Oxylene, respectively, significantly mitigating the environmental and health hazards. Furthermore, 2-Methylanisole was chosen for the carbon ink, reinforcing our commitment to safer and much cheaper production processes.

The results of our approach showed that the R2R coated PSCs, incorporating carbon electrodes, not only achieved a power conversion efficiency (PCE) of over 10% but also demonstrated extraordinary stability (D1- ISOS). Unencapsulated devices maintained 85% of their initial PCE after 90 days, a testament to the durability that can be achieved alongside environmental consciousness.

These findings do more than just validate the effectiveness of low-toxicity solvents in the fabrication of PSCs. They represent a crucial advancement in making PSC technology a realistic, sustainable option for large-scale solar energy production. By addressing the pivotal issues of toxicity, stability, and cost, our study paves the way for PSCs to transition from laboratory breakthroughs to robust, environmentally responsible, and commercially viable energy solutions, setting a new precedent in the solar energy landscape.