In the relentless pursuit of advanced materials for next-generation optoelectronic devices, two-dimensional (2D) metal halide perovskites have emerged as one of the most promising candidates owing to their unique structural and electronic properties. These atomically thin perovskite layers exhibit excellent optical absorption, charge transport capabilities, and environmental stability, making them highly attractive for applications in solar cells, light-emitting diodes, and photodetectors. Yet, despite the remarkable progress made in perovskite research, conventional 2D perovskites still face inherent limitations related to their structural diversity and stability, which restrict their widespread application in commercial technologies. A groundbreaking study led by Lin, Tang, Nian, and colleagues now introduces an innovative class of 2D perovskites characterized by intralayer bidentate coordination, heralding a new era in perovskite chemistry and device engineering.
Traditional two-dimensional perovskite architectures predominantly fall into three categories: Ruddlesden–Popper (R-P), Dion–Jacobson (D-J), and alternating cation phases. Each class is defined by the nature of its organic spacer cations as well as the way these cations interact with the inorganic perovskite layers, affecting the overall crystal packing, stability, and optoelectronic properties. The R-P phase typically features monodentate ammonium ligands that separate perovskite sheets via van der Waals interactions, whereas the D-J phase involves bidentate ligands that bridge across layers. Despite their success, these conventional phases still exhibit limited binding strength within the perovskite lattice, which can lead to structural degradation under operational stresses such as heat, moisture, and prolonged illumination.
Addressing these challenges, the research team designed and synthesized a class of bidentate ligands that incorporate a rigid core structure appended with two ipsilateral ammonium-terminated linker groups. This architecture allowed for the formation of a previously unexplored 2D perovskite phase referred to as the “B-D phase,” named after the characteristic intralayer bidentate coordination chemistry. Unlike the traditional D-J ligands that connect layers vertically, the B-D ligands coordinate within the same perovskite plane, effectively reinforcing the lattice from within and enhancing the mechanical sturdiness and chemical robustness of the materials.
Central to the study was the successful crystallization of single crystals incorporating these novel B-D ligands. Detailed structural characterization confirmed the presence of intralayer bidentate coordination which ensures intimate binding between the organic ligand and the adjacent inorganic lead halide layers. This unique bonding strategy not only diversifies the range of achievable perovskite structures but also significantly increases lattice integrity, effectively reducing the propensity for phase segregation or ion migration — phenomena that have long plagued perovskite-based devices.
To elucidate the nature of interactions and energetic stabilization within the newly formed B-D phase, the researchers employed rigorous molecular dynamics simulations. These computational experiments demonstrated that the binding energies of the B-D ligands to the inorganic layers were substantially stronger than those observed in traditional R-P and D-J phases. Enhanced binding translates into greater lattice coherence and improved resistance to thermally induced lattice distortions or chemical degradation pathways, which are detrimental to device performance and longevity.
The practical implications of this molecular-level reinforcement became all the more evident when polycrystalline thin films of the B-D phase perovskites were fabricated and subjected to thermal stability testing. Remarkably, these films exhibited thermal resistance improvements of an extraordinary 1,600% and 140% compared to R-P and D-J analogues, respectively. Such a dramatic increase in thermal robustness is a pivotal advance, considering that thermal fluctuations are one of the primary challenges in the long-term operation of perovskite-based photovoltaics and optoelectronics.
Moreover, these superior thermal properties directly translated into improved optoelectronic device performance. Photovoltaic devices constructed with the B-D phase perovskite thin films displayed higher power conversion efficiencies surpassing those fabricated from conventional R-P and D-J phases. Beyond efficiency, the devices exhibited markedly extended operational stability under continuous illumination and thermal stress, underscoring the potential of these materials for real-world energy harvesting applications where durability is as critical as initial performance.
The B-D ligand strategy not only enhances key performance parameters but also marks a paradigm shift in ligand engineering for hybrid perovskites. By manipulating the spatial positioning and coordination behavior of organic cations within the perovskite lattice, the study pioneers a new dimension of chemical control that could be extended to a vast array of metal halide perovskite compositions and beyond. This approach opens unexplored avenues for tailoring physicochemical properties by synthetic design, overcoming fundamental limitations of known 2D perovskite phases.
Further insights were gained into the mechanisms underpinning the stability enhancement via a combination of spectroscopic and microscopic characterizations. The intimate intralayer bidentate binding restricts the vibration and rotational motions of the organic ligands, reducing lattice disorder and defect formation. Consequently, charge carriers in the perovskite layers experience fewer traps, enhancing charge mobility and recombination lifetimes, which collectively improve the optoelectronic performance metrics.
This research also addresses the scalability and processability challenges commonly associated with the integration of complex ligands into perovskite films. The B-D ligands exhibit excellent solubility and compatibility with common solution-processing techniques, enabling facile fabrication of uniform polycrystalline films without compromising crystallinity or phase purity. Such manufacturability is crucial for bridging the gap between laboratory-scale discoveries and industrial-level optoelectronic applications.
The significance of this work extends beyond photovoltaics and light emission, as the enhanced structural stability and electronic properties of the B-D phase 2D perovskites potentially benefit a broad spectrum of hybrid functional materials. Spintronic devices, sensors, and photocatalytic systems may also leverage these materials’ robust and tunable architectures, stimulating cross-disciplinary innovation.
In summary, the introduction of intralayer bidentate ligands into the 2D metal halide perovskite framework represents a major breakthrough in materials chemistry and optoelectronic device engineering. This innovative structural motif not only broadens the landscape of stable and efficient perovskite phases but also exemplifies the power of molecular design in overcoming longstanding material limitations. As the field advances, such ligand-based strategies promise to unlock unprecedented performance and durability, propelling metal halide perovskites to the forefront of next-generation technologies.
The research led by Lin, Tang, Nian, and their collaborators heralds a watershed moment in the journey toward more robust, efficient, and versatile hybrid perovskite materials. By fundamentally reimagining the interplay between organic and inorganic components at the nanoscale, they set the stage for a new class of optoelectronic materials that marry structural elegance with unparalleled functional resilience. As these materials transition from the lab bench to real-world applications, the prospects for sustainable solar energy and flexible electronics appear more promising than ever.
Subject of Research:
Two-dimensional (2D) metal halide perovskites with intralayer bidentate ligand coordination for enhanced structural stability and optoelectronic performance.
Article Title:
Intralayer bidentate diammoniums for stable two-dimensional perovskites
Article References:
Lin, C., Tang, Y., Nian, Z. et al. Intralayer bidentate diammoniums for stable two-dimensional perovskites. Nat. Chem. (2026). https://doi.org/10.1038/s41557-025-02038-w
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