Perovskite on flexible foil: from lab to real-world application

Perovskite solar cells (PSCs) have attracted substantial interest in the photovoltaic community, owning to a very fast achievement in its efficiencies greater than 25%. However, for any solar cell to enter the market and maintain its share, two main additional milestones need to be achieved: long-term operational stability and industrial production capability. This was the focus of my research, where I investigated novel device architectures that are stable over the state-of-the-art and optimized scalable coating techniques for fabricating PSCs on flexible substrates. Manufacturing on plastic foils offers several new value propositions by exploring new applications requiring unique form factors and high specific power. Further, to investigate the technology readiness level, we developed an animal tracking collar powered by PSCs for monitoring the European bison in Ukraine. The thesis can be divided into three main parts: stability, upscaling, and real-world application. Stability: In chapter 4, we demonstrate highly efficient, stable, and flexible perovskite solar cells of large areas, utilizing a carbon back-contact electrode in a p–i–n cell configuration. We enabled good electronic contact at the interface with carbon by inserting an ultrathin buffer layer before the carbon coating. Solar cells of such structures reach a power conversion efficiency of 15.18% on PET foil (device area of 1 cm2). We performed impedance spectroscopy and transient decay measurements to understand the electron transport characteristics. Furthermore, we demonstrate excellent operational (maximum power point) and thermal (85 °C) stability of these devices over 1000 h of aging. Upscaling: In chapter 5, we report the development of a large-area blade-coating of wide- and narrow-bandgap perovskite photoactive layers on flexible substrates. Optimized sub-junctions are assembled into the 4-terminal tandem solar modules, delivering 15.3% efficiency for the 50 cm2 active area. Applied surface modification strategies and interfacial engineering for both perovskite sub-modules, together with the robust, flexible encapsulation, deliver promising reliability results achieved in different indoor and outdoor aging tests. Real-world application: In chapter 6, we showcase the first real-world application for PSCs by integrating the modules into an animal tracking collar for powering the IoT device that monitors the European bison in Ukraine. The tracking collars were developed by cooperating with World Wide Fund for Nature (WWF) Ukraine (local partner), WWF Poland, and West pomeranian Nature Society on the implementation of the initiative "Perovskite Solar Module Enabled IoT Asset Tracking for Wildlife Conservation" under the Challenge Fund: Polish Solutions for SDGs.