| Apr 12, 2023 |
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(Nanowerk News) The Yin-Yang theory, an ancient Chinese philosophy, posits that Yin-Yang forces are interdependent and work in opposition to each other to maintain balance. Drawing inspiration from this theory, a research team led by Prof. GUO Xin and Prof. LI Can from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) recently uncovered the origin of stability in Dion-Jacobson (DJ) phase two-dimensional (2D) perovskite materials.
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Their findings were published in Joule (“Revealing stability origin of Dion-Jacobson 2D perovskites with different-rigidity organic cations”).
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DJ 2D perovskites, a category of organic-inorganic hybrid perovskite materials, have been extensively utilized in various optoelectronic applications. While traditional 3D perovskites possess inherently low stability, 2D perovskites, including the Ruddlesden-Popper (RP) phase and DJ phase, offer greater stability. DJ 2D perovskites, which are based on organic diammonium cations and inorganic lead iodide octahedra, have higher structural stability than their RP counterparts.
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Nevertheless, certain DJ 2D perovskites are not as robust and degrade more easily than RP 2D perovskites, which has sparked debate over their stability. These conflicting research findings have prompted scientists to thoroughly investigate the stability mechanism of DJ 2D perovskites with different diammonium cations.
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In their study, the researchers demonstrated that the stability of DJ 2D perovskites hinges on the rigidity of organic diammonium cations, which can induce the co-adaptation of organic and inorganic components to stabilize the 2D structure. Specifically, medium cation rigidity enables organic diammoniums and inorganic octahedra to adjust their geometries in a mutually accommodating manner, ultimately achieving a stabilized state.
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This mechanism may offer guidance to researchers aiming to intentionally manipulate the stability of DJ 2D perovskites by modifying cation rigidity. Prof. GUO explained that, akin to the Yin-Yang theory, organic cations and inorganic octahedra in DJ 2D perovskites are interconnected through alternating hydrogen bonds. When both components can adjust their geometries to accommodate one another, strong connections are formed. In this context, organic cations with moderate rigidity play a crucial role in the intercoordination process, as they possess a certain degree of freedom to regulate geometry, allowing the inorganic component to alter its configuration accordingly.
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