Cegiełka Daria M, Bodek Łukasz, Zharnikov Michael, Cyganik Piotr
Jagiellonian University, Doctoral School of Exact and Natural Sciences, Łojasiewicza 11, 30-348 Kraków, Poland.
Jagiellonian University, Faculty of Physics, Astronomy and Applied Computer Science, Smoluchowski Institute of Physics, Łojasiewicza 11, 30-348 Kraków, Poland.
J Phys Chem Lett. 2025 Apr 3;16(13):3343-3350. doi: 10.1021/acs.jpclett.5c00500. Epub 2025 Mar 25.
Self-assembled monolayers (SAMs) are broadly used for molecular engineering of surfaces and interfaces, which demands control over their structure and properties. An important tool in this context is the so-called odd-even effects exploiting the dependence of the SAM structure on the parity of the number of building blocks forming the backbone of SAM-building molecules. Even though these effects influence parameters crucial for SAM applications, they have been mainly studied on coinage metals (Au and Ag) until now. Here, using the series of biphenyl-substituted carboxylic acids (BPnCOO, = 0-4), we show that structural odd-even behavior occurs as well on technologically relevant surface of naturally oxidized aluminum (representative of other oxide surfaces), with the monolayers exhibiting higher packing density and lower molecular inclination than the analogs. Despite these structural changes, the SAM desorption energy remains nearly constant at a high value (∼1.5 eV) making BPnCOO/AlO a promising system for organic electronics applications.
自组装单分子层（SAMs）广泛应用于表面和界面的分子工程，这需要对其结构和性质进行控制。在这种情况下，一个重要的工具是所谓的奇偶效应，它利用SAM结构对构成SAM构建分子主链的构建单元数量奇偶性的依赖性。尽管这些效应影响着SAM应用的关键参数，但到目前为止，它们主要是在贵金属（金和银）上进行研究的。在这里，我们使用一系列联苯取代的羧酸（BPnCOO，n = 0 - 4）表明，在天然氧化铝的技术相关表面（代表其他氧化物表面）上也会出现结构奇偶行为，其中n为偶数的单分子层比n为奇数的类似物表现出更高的堆积密度和更低的分子倾斜度。尽管有这些结构变化，SAM的解吸能量仍保持在一个较高的值（约1.5 eV）且几乎恒定，这使得BPnCOO/AlO成为有机电子应用的一个有前景的体系。
