Gravelsins Steven, Park Myung Jin, Niewczas Marek, Hyeong Seok-Ki, Lee Seoung-Ki, Ahmed Aftab, Dhirani Al-Amin
Department of Chemistry, University of Toronto, Toronto, ON, Canada.
Department of Materials Science & Engineering, McMaster University, Hamilton, ON, Canada.
Commun Chem. 2022 Aug 29;5(1):103. doi: 10.1038/s42004-022-00723-2.
A central goal in molecular electronics and optoelectronics is to translate tailorable molecular properties to larger materials and to the device level. Here, we present a method to fabricate molecularly cross-linked, self-assembled 2D nanoparticle sheets (X-NS). Our method extends a Langmuir approach of self-assembling gold nanoparticle (NP) arrays at an air-water interface by replacing the liquid sub-phase to an organic solvent to enable cross-linking with organic molecules, and then draining the sub-phase to deposit films. Remarkably, X-NS comprising conjugated oligophenylene dithiol cross-linkers (HS-(CH)-SH, 1 ≤ n ≤ 3) exhibit increasing conductance with molecule length, ~6 orders of magnitude enhancement in UV-Vis extinction coefficients, and photoconductivity with molecule vs. NP contributions varying depending on the excitation wavelength. Finite difference time domain (FDTD) analyses and control measurements indicate that these effects can be modeled provided the local complex dielectric constant is strongly modified upon cross-linking. This suggests quantum hybridization at a molecule-band (q-MB) level. Given the vast number of molecules and nano-building blocks available, X-NS have potential to significantly increase the range of available 2D nanosheets and associated quantum properties.
分子电子学和光电子学的一个核心目标是将可定制的分子特性转化为更大尺寸的材料以及器件层面的特性。在此，我们展示了一种制备分子交联的自组装二维纳米颗粒片（X-NS）的方法。我们的方法扩展了一种在空气-水界面自组装金纳米颗粒（NP）阵列的朗缪尔方法，即将液相下层替换为有机溶剂，以实现与有机分子的交联，然后排干下层液相来沉积薄膜。值得注意的是，由共轭低聚亚苯基二硫醇交联剂（HS-(CH) -SH，1≤n≤3）组成的X-NS表现出电导率随分子长度增加、紫外-可见消光系数增强约6个数量级，以及光导率，其中分子与NP的贡献随激发波长而变化。时域有限差分（FDTD）分析和对照测量表明，只要交联时局部复介电常数发生强烈改变，这些效应就可以被建模。这表明在分子-能带（q-MB）水平上存在量子杂化。鉴于有大量可用的分子和纳米构建块，X-NS有潜力显著增加可用二维纳米片的范围以及相关的量子特性。
