Design Synthesis Stability Aspects and Field Study of Thermoplastic Polyurethanes as Encapsulants for Perovskite Solar Cells

Abstract

In the past decade perovskite solar cells (PSCs) have received attention and achieving notable advancements in power conversion efficiency (PCE). The best achieved power conversion efficiency for single junction device is around 26.1% (device active area 1 cm2). Despite the promise of perovskite solar cells efficiency comparable to the well-established silicon solar cell technology, their poor lifetime and stability remain significant challenges hindering commercialization. Addressing these issues is crucial for advancing this technology. Beyond developing stable perovskite materials and optimizing device architecture, implementing a robust barrier or encapsulation with high-performance materials is essential. Polymer-based encapsulation methods offer a viable solution, balancing processing costs with enhanced device lifetime. With this consideration, in the first and second working chapter, we have synthesized a series of thermoplastic polyurethanes (TPUs) through a rational design by utilizing polyols having different molecular weights and diverse isocyanates (aromatic and aliphatic). Thorough characterization of these TPUs (ASTM and ISO standards) along with structureand#8722;property relationship studies were carried out for the first time and were then used as the encapsulation material for PSCs. The prepared TPUs were robust and adhered well with the glass substrate, and the use of low temperature during the encapsulation process avoided the degradation of the perovskite absorber and other organic layers in the device stack newline