Orienting and shaping organic semiconductor single crystals through selective nanoconfinement
Orienting and shaping organic semiconductor single crystals through selective nanoconfinement
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DOI：
10.1039/d0sm01928c
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发表时间：
2021-04-07
期刊：
影响因子：
3.4
通讯作者：
Lee, Stephanie S.
中科院分区：
文献类型：
--
作者：
Alaei, Aida;Zong, Kai;Lee, Stephanie S.
对于沿不同晶体方向表现出各向异性电荷传输的有机半导体晶体，纳米限制是一种通过将快速晶体生长方向与纳米限制支架的无限制轴对齐来控制晶体取向的强大策略。在这里，提出了与溶液处理的小分子晶体中的晶体形态、支架几何形状和取向控制相关的设计规则。具体来说，n=1的有机半导体三异丙基甲硅烷基乙炔基吡喃针状晶体和n=2的苝板状晶体是从纳米限制支架内的溶液中生长出来的，这些纳米限制支架包含尺寸为m=1的圆柱形纳米孔，代表沿着圆柱轴的一个无限制尺寸，以及那些包含尺寸为m=2的纳米柱阵列的纳米约束支架。对于m=n系统，在晶体取向的同时保留了天然晶体生长习性。 n = m 方向由支架的几何形状决定。另一方面，对于 n 不等于 m 的系统，方向控制被限制在单个平面内，平行于或垂直于衬底表面。有趣的是，在圆柱形纳米孔（n > m）中生长的苝晶体也观察到对晶体形状的控制。在纳米孔内，晶体生长被限制在一个方向上，形成针状形态。一旦生长进行到支架表面上方，晶体就会采用其天然生长习性，形成具有凹角的不对称 T 形单晶。这些发现表明，具有空间变化维度的纳米多孔支架可用于生长复杂形状的单晶。
For organic semiconductor crystals exhibiting anisotropic charge transport along different crystallographic directions, nanoconfinement is a powerful strategy to control crystal orientation by aligning the fast crystallographic growth direction(s) with the unconfined axis(es) of nanoconfining scaffolds. Here, design rules are presented to relate crystal morphology, scaffold geometry, and orientation control in solution-processed small-molecule crystals. Specifically, organic semiconductor triisopropylsilylethynyl pyranthrene needle-like crystals with a dimensionality of n = 1 and perylene platelike crystals with n = 2 were grown from solution within nanoconfining scaffolds comprising cylindrical nanopores with a dimensionality of m = 1, representing one unconfined dimension along the cylinder axis, and those comprising nanopillar arrays with a dimensionality of m = 2. For m = n systems, native crystal growth habits were preserved while the crystal orientation in n = m direction(s) was dictated by the geometry of the scaffold. For n not equal m systems, on the other hand, orientation control was restricted within a single plane, either parallel or perpendicular to the substrate surface. Intriguingly, control over crystal shape was also observed for perylene crystals grown in cylindrical nanopores (n > m). Within the nanopores, crystal growth was restricted along a single direction to form a needle-like morphology. Once growth proceeded above the scaffold surface, the crystals adopted their native growth habit to form asymmetric T-shaped single crystals with concave corners. These findings suggest that nanoporous scaffolds with spatially-varying dimensionalities can be used to grow single crystals of complex shapes.