Mathur Avi, Fan Hua, Maheshwari Vivek
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):58956-58965. doi: 10.1021/acsami.1c18939. Epub 2021 Dec 1.
The rigid and brittle nature of methylammonium lead iodide (MAPbI) polycrystalline films limits their application in stretchable devices due to rapid deterioration in performance on cycling. By incorporation of polymer chains in the MAPbI films, a strategy to alter the mechanical modulus and the viscoelastic nature of the films has been developed. Combining this with flexible nanochain electrodes, highly stretchable and stable perovskite devices have been fabricated. The resultant polymer-MAPbI photodetector exhibits ultralow dark currents (∼10 A) and high light switching ratios (∼10) and maintains 75% of performance after 30 days. The viscoelastic nature and lower modulus of the polymer improve the energy dissipation in the polymer-MAPbI devices; as a result, they maintain 52% of the device performance after 10000 stretching cycles at 50% strain. The difference in the mechanical behavior is clearly observed in the failure mode of the two films. While rapid catastrophic cracking is observed in MAPbI films, the intensity and size of such crack formation are highly limited in polymer-MAPbI films, which prevent their failure.
甲基碘化铅（MAPbI）多晶薄膜的刚性和脆性使其在可拉伸器件中的应用受到限制，因为在循环过程中其性能会迅速恶化。通过在MAPbI薄膜中引入聚合物链，已开发出一种改变薄膜机械模量和粘弹性的策略。将此与柔性纳米链电极相结合，制备出了高度可拉伸且稳定的钙钛矿器件。所得的聚合物-MAPbI光电探测器表现出超低暗电流（约10 A）和高光开关比（约10），并在30天后仍保持75%的性能。聚合物的粘弹性性质和较低模量改善了聚合物-MAPbI器件中的能量耗散；因此，在50%应变下进行10000次拉伸循环后，它们仍保持52%的器件性能。在两种薄膜的失效模式中可以清楚地观察到机械行为的差异。虽然在MAPbI薄膜中观察到快速的灾难性开裂，但在聚合物-MAPbI薄膜中，这种裂纹形成的强度和尺寸受到极大限制，从而防止了它们的失效。
