Hydrogen Bonds in Perovskite for Efficient and Stable Photovoltaic^†

Owing to their distinctive optical and physical properties, organic-inorganic hybrid perovskite materials have gained significant attention in the field of electronic devices, especially solar cells. The achievement of high-performance solar cells hinges upon the utilization of top-notch perovskite thin films. Nevertheless, the fabrication process involving solutions and the polycrystalline nature of perovskite result in the emergence of numerous defects within the perovskite films, consequently exerting a deleterious influence on the overall performance and stability of the devices. Improving the performance and stability of perovskite solar cells by additive engineering to suppress/passivate defects is a viable approach, which involves hydrogen bond interactions in these device engineering processes. This review explores the intrinsic hydrogen bonds in methylammonium and formamidium lead triiodide, while also considering cation rotations, phase transitions, and stability. Moreover, the review classifies additives into distinct categories, including organic small molecules, polymers, nanodots, classical salts, ionic liquids, and molten salts. The various forms and characterization techniques of hydrogen bonds are discussed, as well as their potential synergistic effects in conjunction with other chemical interactions. Furthermore, this review offers insights into the potential utilization of hydrogen bonds to further enhance the performance and stability of devices.

Key Scientists

In 2009, Tsutomu Miyasaka et al. prepared the first perovskite solar cell, which kicked off the research on perovskite light-absorbing materials. However, the use of liquid electrolytes led to device instability. The transition to all-solid-state perovskite solar cells was realized by Nam-Gyu Park's team in 2012, which was the beginning of high-efficiency perovskite solar cells. Subsequently, a number of scientists have innovated the preparation ground process. Methods such as two-step deposition by Michael Grätzel in 2013 and anti-solvent extraction by Sang II Seok's team in 2014 were instrumental in advancing the development of perovskite. Liyuan Han's team then increased the cell's working area to 1 cm² without compromising performance, making it possible to compare the performance metrics of perovskite solar cells with those of other types of solar cells on the same scale. Recently, You's team and Pan's team kept updating the world record by obtaining certified efficiencies of 25.6% and 25.8% in 2022 and 2023, respectively.