The Impact of the Crystallization Processes on the Structural and Optical Properties of Hybrid Perovskite Films for Photovoltaics
The Impact of the Crystallization Processes on the Structural and Optical Properties of Hybrid Perovskite Films for Photovoltaics
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DOI：
10.1021/jz501877h
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发表时间：
2014-11-06
影响因子：
5.7
通讯作者：
Petrozza, Annamaria
中科院分区：
文献类型：
--
作者：
Grancini, Giulia;Marras, Sergio;Petrozza, Annamaria
我们研究了有机铅混合卤化物钙钛矿薄膜的结构和光学性质之间的关系作为结晶机制的函数。对于甲基铵三碘化铅，有机阳离子在无机笼内重排，从在中孔支架中生长的晶体移动到在平坦基底上生长的更大的定向晶体。这降低了形成笼的键所感受到的应变，并影响其中有机阳离子的运动，从而影响半导体的光吸收光谱开始时的电子跃迁。此外，我们证明，在混合卤化物钙钛矿，虽然Cl-离子是不存在的单位电池中的可检测的浓度，他们驱动的结晶动力学。这在结晶期间诱导从分子，即，有机-无机部分排列，达到纳米-介观水平，即，具有各向异性形状的较大晶体。最后，我们表明，虽然氯主要是驱逐从平面薄膜制成的大晶体，在氧化物介孔支架的存在下，他们部分保留在复合材料。
We investigate the relationship between structural and optical properties of organo-lead mixed halide perovskite films as a function of the crystallization mechanism. For methylammonium lead tri-iodide, the organic cations rearrange within the inorganic cage, moving from crystals grown in a mesoporous scaffold to larger, oriented crystals grown on a flat substrate. This reduces the strain felt by the bonds forming the cage and affects the motion of the organic cation in it, influencing the electronic transition at the onset of the optical absorption spectrum of the semiconductor. Moreover, we demonstrate that in mixed-halide perovskite, though Cl- ions are not present in a detectable concentration in the unit cell, they drive the crystallization dynamics. This induces a preferential order during crystallization, from a molecular, i.e., organic-inorganic moieties arrangement, to a nano-mesoscopic level, i.e., larger crystals with anisotropic shape. Finally, we show that while Cl is mainly expelled from flat films made of large crystals, in the presence of an oxide mesoporous scaffold they are partially retained in the composite.