Solution-Deposited Ferroelectric BiFeO₃ Perovskite-Based Films: A Spotlight on Their Manifold Applications in...

The advancement of smart materials is crucial for addressing the cross-cutting challenges of contemporary society. These materials are expected to help raise living standards through the expansion of smart cities, efficient management of natural resources, pollution control, and improvements in social welfare. Consequently, the multifunctionality of ferroelectric oxides makes them ideal candidates for meeting these demands. Among ferroelectric oxide materials, bismuth ferrite (BiFeO₃) stands out as a multiferroic compound with ferroelectric, ferroelastic, and antiferromagnetic properties at room temperature. It also has one of the lowest bandgaps among ferroelectrics, making it a photoferroelectric compound with both photovoltaic and photocatalytic properties. These responses can be fine-tuned by partially substituting Fe³⁺ ions with selected cations or by creating solid solutions between BiFeO₃ and other ferroelectric perovskites. BiFeO₃-based thin-film materials are regarded as ideal for harnessing the diverse properties of BiFeO₃ in emerging technologies. Chemical solution deposition methods facilitate the design of crystallization pathways for metal oxides, such as BiFeO₃ thin films, making them essential for developing low-temperature strategies that offer benefits ranging from reduced environmental impact to lower manufacturing costs. A greater challenge lies in preparing BiFeO₃ films at temperatures compatible with their direct integration into flexible systems using polymeric substrates. This spotlight article highlights, through examples from our group's research over the past decade, the various applications of BiFeO₃-based perovskite thin films in emerging technologies. Interest is not only in devices based on rigid single-crystal substrates, like silicon, but also in those using flexible polymer substrates. Here, we discuss the promising opportunities of using low-cost, high-throughput solution deposition methods for producing multifunctional BiFeO₃-based perovskite films for future applications.