Novel Chevron And Banana-Shaped Materials For Photonic And Electrical Devices

最近在克兰菲尔德的一项发现，通过Langmuir-Blodgett （LB）技术，导致了没有脂肪尾部的分子的非中心对称排列，薄膜表现出高的二阶敏感性（J. Mater）。化学，2002,12,2181)和分子矫正(J.物理。化学。[j] .自然科学进展，2002,22(1):1 - 4。这些分子不同于那些通常被认为适合LB沉积的分子，因为它们具有chevrons而不是线性分子结构，尽管如此，正在进行的研究已经证明75%的样品是排列的，尽管迄今为止只有四个。这一建议涉及到这一发现的发展，并受到赫尔大学目前对香蕉状液晶的研究的推动，香蕉状液晶的基本结构与用于校准的chevrons相同。将尝试将香蕉状材料的分子几何和组织联系起来，并利用它们独特的液晶相。LB沉积和分子自组装的类似物将被合成，后者是通过分子和镀金衬底之间的硫醇连接来实现的。分子将在理论上建模，以影响排列，从而影响非线性光学和非线性电学性质，目的是优化二次谐波强度和电流整流比。

A recent discovery at Cranfield resulted in the non-centrosymmetric alignment of molecules without aliphatic tails by the Langmuir-Blodgett (LB) technique, the films exhibiting a high second-order susceptibility (J. Mater. Chem. 2002, 12, 2181) and molecular rectification (J. Phys. Chem. B 2002, 106, 12158). The molecules differ from those normally considered suitable for LB deposition by having a chevron-shaped rather than a linear molecular structure but, nonetheless, on-going studies have demonstrated alignment in 75% of samples, albeit of only four so far investigated.This proposal concerns a development of the discovery and is driven by current research at Hull on banana-shaped liquid crystals, which have the same basic structure as the chevrons for alignment. An attempt will be made to correlate the molecular geometry and organisation of banana-shaped materials and to exploit their unique liquid crystalline phases. Analogues for both LB deposition and molecular self-assembly will be synthesised, the latter being achieved via a thiol link between the molecule and a gold-coated substrate.Molecules will be theoretically modelled to influence the alignment and consequently, the nonlinear optical and nonlinear electrical properties, with the aim of optimising the second-harmonic intensity and the current rectification ratio.