Exploring 2D perovskite chemistry: A new frontier for efficient and stable solar cells
image: Schematic illustration of 2D perovskite structure with different n values
Credit: Xinyu Zhao, Jiajun Li, Jinzhan Cheng, Xuezheng Liu & Xiaoming Zhao.
Perovskite solar cells (PSCs) have rapidly emerged as one of the most promising photovoltaic technologies due to their high power conversion efficiency (PCE), which has surpassed 26% in single-junction devices. However, long-term stability remains a major hurdle for their commercialization. Three-dimensional (3D) perovskites, while efficient, are highly sensitive to moisture, oxygen, and thermal stress. To address these challenges, researchers have turned to two-dimensional (2D) perovskites, which offer superior environmental stability due to their layered structure and hydrophobic organic spacers. Despite their advantages, 2D perovskites have generally shown lower efficiency and charge transport limitations compared to their 3D counterparts.
A recent review published in Frontiers in Energy by researchers at Nanjing University of Aeronautics and Astronautics provides a comprehensive overview of the latest developments in 2D perovskite chemistry. The paper explores the structural, optoelectronic, and stability-related properties of 2D perovskites, focusing on how they can be engineered to complement or enhance 3D perovskites in solar cell applications. The review also outlines key strategies for overcoming the limitations of 2D perovskites, including phase purity control, crystal orientation tuning, and chemical engineering of organic spacers.
The study highlights that 2D perovskites exhibit significantly improved stability due to their high formation energy and resistance to ion migration. Their layered structure, composed of alternating organic and inorganic sheets, acts as a barrier against moisture and suppresses degradation pathways commonly seen in 3D perovskites. The review identifies three main structural phases—Ruddlesden-Popper (RP), Dion-Jacobson (DJ), and Alternating Cation in the Interlayer (ACI)—each offering unique advantages in terms of stability and optoelectronic performance.
To enhance charge transport and device efficiency, researchers are developing methods to achieve vertical crystal orientation and phase-pure 2D films. Techniques such as solvent vapor annealing, surface crystallization modulation, and solvent engineering have shown promise in aligning 2D layers for better charge mobility. Additionally, the incorporation of conjugated organic ligands and halide engineering enables tunable bandgaps and improved charge separation, making 2D perovskites more suitable for photovoltaic applications.
The review also emphasizes the role of 2D/3D hybrid structures, where a thin 2D layer is used to passivate the surface of a 3D perovskite. This approach combines the high efficiency of 3D perovskites with the enhanced stability of 2D materials, resulting in solar cells with improved long-term performance.
This comprehensive review underscores the transformative potential of 2D perovskites in next-generation solar technologies. By addressing fundamental issues related to phase purity, crystal orientation, and interfacial engineering, 2D perovskites can play a critical role in developing stable, efficient, and scalable photovoltaic devices. The insights presented offer a roadmap for researchers and industry stakeholders to advance perovskite solar cell technology toward commercial viability, particularly for applications requiring long-term durability and environmental resilience.