Future Perspectives of Perovskite Solar Cells: Metal Oxide-Based Inorganic Hole-Transporting Materials

Abstract

The hybrid organic-inorganic metal halide perovskite solar cell (PSC) is a promising and emerging technology with certified efficiency currently reaching above 25%. Despite unprecedented development, PSCs based on operationally instable and extremely expensive organic hole-transporting materials (HTMs) such as N 2, N 2', N 2', N 7, N 7, N 7', N 7'-octakis(4-methoxyphenyl)-9, 9'-spirobi[9H-fluorene]-2, 2', 7, 7'-tetramine or poly[bis(4-phenyl)(2, 4, 6-trimethylphenyl)amine] are far from commercialization. There is an urge to develop new sustainable materials to combat these issues associated with organic-based HTMs. This chapter focuses on the significance of metal oxide-based inorganic functional materials as HTMs in different PSC architectures. The first section of the chapter presents the basics of PSC technology, including working principles, device structures, components, and challenging issues. The following section introduces sustainable hole conductors as well as an outline of the current routes to enhance long-term operational stability and reduce material cost using innovative approaches. The prerequisites of a novel HTM and compatibility with neighboring layers are also briefly discussed. In the last section, highly promising metal oxide-based inorganic HTMs and current progress are highlighted comprehensively to illustrate the importance of inorganic materials in terms of the state-of-the-art of PSCs. Overall, this chapter provides a roadmap of the current demands and future research directions to address the main critical concerns of PSCs that must be tackled to mitigate the major barriers on the pathway to upscaling applications. © 2021 Elsevier Inc. All rights reserved.