Current Efforts to Make Perovskite Solar Cells Industrially Viable

Photovoltaic (PV) technology has evolved rapidly in the past few decades and now encompasses a large variety of materials and device structures. A perovskite solar cell (PSC) is a photovoltaic device which includes a perovskite-structured compound, most commonly a hybrid organic-inorganic lead halide-based material, as the light-harvesting active layer. These devices are cheap to produce and simple to manufacture at a laboratory level. Solar cell efficiencies of devices using these materials have increased from 3.8% in 2009 to 22.1% in early 2016, making this the fastest-advancing solar technology to date. Therefore, it is clear that – with the potential of achieving even higher efficiencies – PSCs have become commercially attractive, and a few issues should be fixed soon. A key aspect to be taken into account in any PV technology is the operational durability of these systems in outdoor conditions. Clearly, loss of performance during operation represents a significant drawback and limitation for their commercialization. In this context, the large compositional flexibility of polymeric materials as well as their proven easy processability may be of great help in imparting improved durability to PV systems. We show that rapid light-induced free-radical polymerization at ambient temperature produces multifunctional fluorinated photopolymer coatings that confer luminescent and easy-cleaning features on the front-side of the devices, while concurrently forming a strongly hydrophobic barrier toward environmental moisture on the back contact side. The luminescent photopolymers re-emit ultraviolet light in the visible range, boosting perovskite solar cells efficiency to nearly 19% under standard illumination. Coated devices reproducibly retain their full functional performance during prolonged operation, even after a series of severe aging tests carried out for more than 6 months. The industrialization of PSCs also requires the development of processes different with respect to those used in academic laboratories. For example, lab-scale PSC preparation is based on spin-coating technique, that is not transferable on a large scale. In this contribution we will also show the alternative strategies proposed by the scientific community to fabricate solar cells components on large areas.