Large-Area Uniaxial-Oriented Growth of Free-Standing Thin Films at the Liquid–Air Interface with Millimeter-Sized Grains
Large-Area Uniaxial-Oriented Growth of Free-Standing Thin Films at the Liquid–Air Interface with Millimeter-Sized Grains
复制标题
具有毫米级颗粒的液-气界面处大面积单轴定向生长的自支撑薄膜
DOI：
10.1021/acsnano.1c07662
复制
发表时间：
2022
期刊：
影响因子：
17.1
通讯作者：
Lian, Jie
中科院分区：
文献类型：
--
作者：
Zhu, Weiguang;Zhang, Yanming;Shen, Junhua;Shi, Yunfeng;Li, Mingxin;Lian, Jie
在原子尺度上操纵材料，并将它们组装成维度可控、单晶质量可控的宏观结构，是巨大的科学挑战。在这里，我们报道了一种通用的溶剂挥发方法来合成在液-气界面上大面积单轴定向生长的自支撑薄膜。晶体在溶液表面成核，在静电作用下旋转成相同的取向，然后合并为大晶体，横向生长成大面积均匀的毫米级颗粒薄膜。横向尺寸仅受容器大小的限制。通过调节溶剂挥发速率(R)和溶质扩散系数(D)可以调节膜厚，并推导出估算膜厚的特征长度L*∼DR。分子动力学(MD)模拟表明，在快速溶剂蒸发过程中，液-气界面存在浓度尖峰，导致薄膜的横向生长。在无机金属卤化物和杂化金属卤化物钙钛矿上都显示了大面积的单轴取向薄膜。溶剂挥发法和薄膜厚度预测关键参数的确定有利于在受控蒸发条件下实现单晶薄膜材料的高通量和规模化生产。
Manipulating materials at the atomic scale and assembling them into macroscopic structures with controlled dimensionalities and single-crystal quality are grand scientific challenges. Here, we report a general solvent evaporation method to synthesize large-area uniaxial-oriented growth of free-standing thin films at the liquid–air interface. Crystals nucleate at the solution surface and rotate into the same orientation under electrostatic interaction and then merge as large crystals and grow laterally into a large-area uniform thin film with millimeter-sized grains. The lateral dimension is confined only by the size of containers. The film thickness can be tuned by adjusting solvent evaporation rate (R) and solute diffusivity (D), and a characteristic length, L*∼DR, was derived to estimate the film thickness. Molecular dynamic (MD) simulations reveal a concentration spike at the liquid–air interface during fast solvent evaporation, leading to the lateral growth of thin films. The large-area uniaxial oriented films are demonstrated on both inorganic metal halides and hybrid metal halide perovskites. The solvent evaporation approach and the determination of key parameters enabling film thickness prediction are beneficial to the high throughput and scalable production of single crystal-quality thin film materials under controlled evaporation conditions.