Quantitative IR Readout of Fulgimide Monolayer Switching on Si(111) Surfaces
Quantitative IR Readout of Fulgimide Monolayer Switching on Si(111) Surfaces
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DOI：
10.1002/adma.201201546
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发表时间：
2013-01-18
影响因子：
29.4
通讯作者：
Allongue, P.
中科院分区：
文献类型：
--
作者：
de Villeneuve, Catherine Henry;Michalik, Fabian;Allongue, P.
光致变色是分子在吸收电磁辐射后发生的可逆结构转变。将偶氮苯衍生物[1]结合到薄膜中[1 - 9]已经引起了纳米技术20年来的巨大兴趣，因为这导致了纳米（光电）电子，[10-13]数据存储[1]和生命科学设备的发展。[15,16]吸附PC化合物还可以调整纳米颗粒和量子点的物理化学性质。[17,18]通过在平面衬底上形成PC的自组装单层（SAM），可以获得“开关表面”，即其润湿特性具有可逆调制的表面，[19,20]这对微流体特别有用这个概念现在被应用于表面的任何特性的切换，如电导，[11,12,21 - 23]，接触电位或功函数。[24-26]开关面也可用来将光转化为机械功绝大多数的开关表面都是用硫代酸盐的SAM在金衬底上实现的一些报道还涉及功能化的h端硅表面[21,22,29]，使用已建立的协议[30,31]来实现Si-C连接，从而确保卓越的热稳定性和化学稳定性。有时也使用硅烷单层膜偶氮苯衍生物在金表面上的光开关或电场开关关键取决于横向位阻，也取决于PC基团与衬底之间的耦合（机械、电子等）开发了许多不同的策略来增加PC化合物周围的自由体积（有关小型文献调查，请参阅参考文献的介绍）。[19,32])，而最优雅的方法是在分子平台上安装偶氮苯基，它结合了垂直和横向控制。[33,34]然而，一种更简单、更通用的方法是将活性分子后锚定在功能化表面上，尽管这种方法尚未经常用于金，而主要用于硅。[21,22,29]个体[25,35,36]和集体分子开关[37]可以通过STM直接成像。表面电导率的变化，使用金属化AFM尖端，[21]和接触电位差[24]也可以评估构象切换。在宏观尺度上，表面的切换通常通过接触角测量来表征[19,29,38,39]，而很少通过监测UV-Vis中的光学特性（折射率，[32,38]反射率，[40]荧光，[41]吸光度）。(35, 42岁)
Photochromism (PC) is the reversible structural transition of a molecule by absorption of electromagnetic radiation. Incorporation of azobenzene derivatives [1] into thin films [1–9] has received tremendous interest since two decades in nanotechnology as this led to the development of nano (opto) electronic,[10–13] data storage [14] and life science devices.[15, 16] Adsorption of PC compounds can also tailor physicochemical properties of nanoparticles and quantum dots.[17, 18]“Switching surfaces”, ie, surfaces with reversible modulation of their wetting properties, were obtained by formation of self assembled monolayers (SAM) of PC species on a planar substrate,[19, 20] which is particularly useful for micro fluidics.[17] This concept is now applied to the switching of any properties of a surface such as conductance,[11, 12, 21–23] contact potential or work function.[24–26] Switching surfaces may also be used to transform light into mechanical work.[27] The vast majority of switching surfaces have been realized using SAM of thiolates on gold substrates.[28] A few reports deal also with functionalized H-terminated silicon surfaces [21, 22, 29] using established protocols [30, 31] to achieve a Si-C linkage, which ensures superior thermal and chemical stability. Silane monolayers were sometimes used.[19] Photo switching or electric field switching of azobenzene derivatives on gold surfaces crucially depends on lateral steric hindrance and also on the coupling (mechanical, electronic etc.) between the PC groups with the substrate.[25] Many different strategies were developed to increase the free volume around the PC compounds (for a mini literature survey, see introduction of Refs.[19, 32]) and the most elegant one, combining both vertical and lateral control is mounting the azobenzene groups on molecular platforms.[33, 34] A more simple and versatile method is however post-anchoring the active molecules onto a functionalized surface, though it has not been frequently used on gold and was mostly used on silicon.[21, 22, 29] Individual [25, 35, 36] and collective molecular switching [37] can directly be imaged by STM. Changes of surface conductance, using a metallized AFM tip,[21] and contact potential difference [24] can also assess conformation switching. On a macroscopic scale, the switching of surfaces is frequently characterized by contact angle measurements [19, 29, 38, 39] and more scarcely by monitoring optical properties in the UV-Vis (refractive index,[32, 38] reflectance,[40] fluorescence,[41] absorbance).[35, 42]