Advances in Hole Transport Materials for Layered Casting Solar Cells

Huge energy consumption and running out of fossil fuels has led to the advancement of renewable sources of power, including solar, wind, and tide. Among them, solar cells have been well developed with the significant achievement of silicon solar panels, which are popularly used as windows, rooftops, public lights, etc. In order to advance the application of solar cells, a flexible type is highly required, such as layered casting solar cells (LCSCs). Organic solar cells (OSCs), perovskite solar cells (PSCs), or dye-sensitive solar cells (DSSCs) are promising LCSCs for broadening the application of solar energy to many types of surfaces. LCSCs would be cost-effective, enable large-scale production, are highly efficient, and stable. Each layer of an LCSC is important for building the complete structure of a solar cell. Within the cell structure (active material, charge carrier transport layer, electrodes), hole transport layers (HTLs) play an important role in transporting holes to the anode. Recently, diverse HTLs from inorganic, organic, and organometallic materials have emerged to have a great impact on the stability, lifetime, and performance of OSC, PSC, or DSSC devices. This review summarizes the recent advances in the development of inorganic, organic, and organometallic HTLs for solar cells. Perspectives and challenges for HTL development and improvement are also highlighted.

Automated summary

The development of renewable energy sources, including solar, wind, and tide, has been driven by the massive energy consumption and depletion of fossil fuels. Among them, solar cells, particularly silicon solar panels, have achieved significant progress and are widely used in various applications. To further advance the application of solar cells, the development of flexible solar cells, such as layered casting solar cells (LCSCs), is highly demanded. Organic solar cells (OSCs), perovskite solar cells (PSCs), and dye-sensitive solar cells (DSSCs) are promising types of LCSCs that can be applied to different surfaces. LCSCs offer cost-effectiveness, scalability, high efficiency, and stability. The different layers of an LCSC, including hole transport layers (HTLs), play a crucial role in the overall structure and performance of a solar cell. This review summarizes recent advancements in inorganic, organic, and organometallic HTLs for solar cells, highlighting perspectives and challenges for their development and improvement.