CNISM and Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano, Italy.
Langmuir. 2013 Jul 2;29(26):8302-10. doi: 10.1021/la400998r. Epub 2013 Jun 20.
In polymer-metal oxide hybrid solar cells, an extremely careful engineering of the interface is required to ensure good device performances. Recently, very promising results have been obtained by functionalizing titanium dioxide (TiO2) by means of 4-mercaptopyridine (4-MPy) molecules, showing the beneficial effect of these molecules on the interface morphology. This study investigates the nature of the interaction of 4-MPy molecules with the TiO2 surface by means of X-ray photoemission spectroscopy. In order to mimic the device processing conditions, our analysis is carried out on molecules adsorbed from solution on a nanocrystalline surface. According to our analysis, 4-MPy molecules (C5H5NS) are likely bound with the oxide through the nitrogen atom. The bonding precedes either via a covalent interaction with Lewis surface sites, or via hydrogen mediation, possibly in the form of hydrogen bonds. Interestingly, in the latter case, we also observe strong changes in the spectroscopic features attributed to the thiol group.
在聚合物-金属氧化物杂化太阳能电池中，需要对界面进行极其精细的工程设计，以确保良好的器件性能。最近，通过用 4-巯基吡啶（4-MPy）分子功能化二氧化钛（TiO2），获得了非常有前景的结果，表明这些分子对界面形态有有益的影响。本研究通过 X 射线光电子能谱研究了 4-MPy 分子与 TiO2 表面的相互作用性质。为了模拟器件处理条件，我们的分析是在纳米晶表面上从溶液中吸附的分子上进行的。根据我们的分析，4-MPy 分子（C5H5NS）很可能通过氮原子与氧化物结合。这种键合要么通过与路易斯表面位的共价相互作用，要么通过氢键进行，可能以氢键的形式进行。有趣的是，在后一种情况下，我们还观察到与硫醇基团有关的光谱特征的强烈变化。
