In line with the goal of engineering the optical bandgaps of renowned, high-performance oxide perovskite piezoelectric materials, champion piezoelectric materials have been doped and co-doped with various elements that show promise in altering the band structures of these piezoelectric compositions. The work on compositional engineering has been progressing largely as planned. A total of 40 sub-compositions and their corresponding ceramics have been fabricated and comprehensively characterized in terms of their physical, optical, and electrical properties. This is considered a significant volume of work. As a foundational result, a comprehensive understanding of the chemical behaviour and evolution of functional properties of the parent compositions has been achieved. This accomplishment has paved the way for further compositional engineering in this project. Furthermore, the work on certain dopants has led to preliminary conclusions that the local chemical environment is crucial in terms of band structure evolution. Different dopants could serve as effective tools for tuning optical and optoelectrical properties for a variety of applications. Among the dopants that have been tested, a pair of elements as co-dopants has shown early signs of success as they have maintained excellent piezoelectricity and simultaneously demonstrated significantly improved dark conductivity, which could indicate a reduced bandgap. A newly discovered electrical behaviour could also contribute to improving the photovoltaic efficiency, one of the project’s ultimate goals. However, the origin and cause of these phenomena require further research in the next stage of this project. In alignment with the goal of enhancing the photovoltaic efficiency of the piezoelectric materials, device configurations have been created and characterized according to the plan. Promising phenomena, including cumulative opto-ferroelectric response and efficiency increase via domain manipulation, have been discovered, holding promise for achieving the project’s goals.
