Application of Hole-Selective Self-Assembled Monolayers in Inverted Perovskite Solar Cells

Hole-transport layer (HTL) is of paramount importance to construct high-performance inverted perovskite solar cells (PSCs) because it not only determines the hole extraction and transport but also influences the quality of perovskite layer. Recently, self-assembled monolayers are adopted as very effective hole-selective layer to construct high-performance inverted PSCs. Compared with conventional HTL, hole-selective self-assembled monolayers (HSSAMs) offer the benefits of minimal material consumption and parasitic absorption, simple and scalable processing, and the versatility in the interface modification. Through molecule design and coating process optimization, the high-quality HSSAMs are obtained, which enable the HSSAM-based inverted PSCs to achieve greatly promoted photovoltaic performance. Herein, the progress of HSSAMs used in inverted PSCs is summarized. First, the structure characteristics of HSSAM molecules are described. Then, the effect of the structure of HSSAM molecules on their function in boosting the device performance and stability is discussed. Furthermore, the deposition strategies to form high-quality HSSAMs for inverted PSCs are analyzed. Finally, the advantages and challenges associated with application of HSSAMs in inverted PSCs are discussed, and the perspectives of the future research trends on HSSAMs for further promoting the performance of inverted PSCs are suggested. Compared with the conventional hole-transport layer used in inverted PSCs, hole-selective self-assembled monolayers provide multiple advantages, including conformal and uniform coating, minimized thickness, negligible optical and resistance loss, and the versatility in the interface modification.image (c) 2024 WILEY-VCH GmbH