Mathur Avi, Li Alexander, Maheshwari Vivek
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
J Phys Chem Lett. 2021 Feb 11;12(5):1481-1489. doi: 10.1021/acs.jpclett.1c00004. Epub 2021 Feb 3.
The integration of polymer chains with organolead halide perovskite (MAPbI) films, leading to enhanced stability and electro-optical performance, is critically affected by the molecular weight of chains. The molecular weight determines the mobility and volume of the chains, which affects the crystallization kinetics and, hence, perovskite grain size. The insulating nature of the chains is another critical factor that affects both ion migration and conduction of electronic charge. The combined effect of these factors leads to optimal performance with the use of medium-length chains. A simple model integrating the two effects accurately fits the response of the polymer-perovskite composite. Further characterization results show that the polymer-perovskite films have a three-layer architecture consisting of nanoscale polymer-rich top and bottom layers. These combined results show that the optimization of performance in polymer-perovskite devices depends critically on the size of the chains due to their multiple effects on the perovskite matrix.
聚合物链与有机铅卤化物钙钛矿（MAPbI）薄膜的整合可提高稳定性和电光性能，但这一过程受到链分子量的严重影响。分子量决定了链的迁移率和体积，进而影响结晶动力学，从而影响钙钛矿晶粒尺寸。链的绝缘性质是另一个影响离子迁移和电荷传导的关键因素。这些因素的综合作用使得使用中等长度的链可实现最佳性能。一个整合了这两种效应的简单模型能够准确拟合聚合物-钙钛矿复合材料的响应。进一步的表征结果表明，聚合物-钙钛矿薄膜具有由纳米级富聚合物顶层和底层组成的三层结构。这些综合结果表明，由于聚合物链对钙钛矿基体有多种影响，聚合物-钙钛矿器件性能的优化关键取决于链的尺寸。
