Kim Doyun, Vasileiadou Eugenia S, Spanopoulos Ioannis, Wang Xuguang, Yan Jinhui, Kanatzidis Mercouri G, Tu Qing
Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77840, USA.
Department of Chemistry, Northwestern University, Evanston, IL, 60201, USA.
Adv Sci (Weinh). 2023 Sep;10(26):e2303133. doi: 10.1002/advs.202303133. Epub 2023 Jul 6.
2D hybrid organic-inorganic perovskites (HOIPs) are commonly found under subcritical cyclic stresses and suffer from fatigue issues during device operation. However, their fatigue properties remain unknown. Here, the fatigue behavior of (C H -NH ) (CH NH ) Pb I , the archetype 2D HOIP, is systematically investigated by atomic force microscopy (AFM). It is found that 2D HOIPs are much more fatigue resilient than polymers and can survive over 1 billion cycles. 2D HOIPs tend to exhibit brittle failure at high mean stress levels, but behave as ductile materials at low mean stress levels. These results suggest the presence of a plastic deformation mechanism in these ionic 2D HOIPs at low mean stress levels, which may contribute to the long fatigue lifetime, but is inhibited at higher mean stresses. The stiffness and strength of 2D HOIPs are gradually weakened under subcritical loading, potentially as a result of stress-induced defect nucleation and accumulation. The cyclic loading component can further accelerate this process. The fatigue lifetime of 2D HOIPs can be extended by reducing the mean stress, stress amplitude, or increasing the thickness. These results can provide indispensable insights into designing and engineering 2D HOIPs and other hybrid organic-inorganic materials for long-term mechanical durability.
二维有机-无机杂化钙钛矿（HOIPs）通常出现在亚临界循环应力下，并且在器件运行过程中会出现疲劳问题。然而，它们的疲劳特性仍然未知。在此，通过原子力显微镜（AFM）系统地研究了典型的二维HOIP（CH₃NH₃）₂PbI₄的疲劳行为。研究发现，二维HOIPs比聚合物具有更强的抗疲劳能力，能够承受超过10亿次循环。二维HOIPs在高平均应力水平下倾向于表现出脆性破坏，但在低平均应力水平下表现为韧性材料。这些结果表明，在低平均应力水平下，这些离子型二维HOIPs中存在塑性变形机制，这可能有助于延长疲劳寿命，但在较高平均应力下会受到抑制。在亚临界载荷下，二维HOIPs的刚度和强度会逐渐减弱，这可能是应力诱导缺陷形核和积累的结果。循环载荷分量可以进一步加速这一过程。通过降低平均应力、应力幅值或增加厚度，可以延长二维HOIPs的疲劳寿命。这些结果可为设计和制造具有长期机械耐久性的二维HOIPs及其他有机-无机杂化材料提供不可或缺的见解。
