Burger Alexandra, Costa Rubén D, Lobaz Volodymyr, Peukert Wolfgang, Guldi Dirk M, Hirsch Andreas
Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, Institute of Organic Chemistry, Henkestrasse 42, 91054 Erlangen (Germany).
Chemistry. 2015 Mar 23;21(13):5041-54. doi: 10.1002/chem.201405039. Epub 2015 Feb 13.
In the current work, we present the successful functionalization and stabilization of P-25 TiO2 nanoparticles by means of N1,N7-bis(3-(4-tert-butyl-pyridium-methyl)phenyl)-4-(3-(3-(4-tert-butyl-pyridinium-methyl)phenylamino)-3-oxopropyl)-4-(3,4-dihydroxybenzamido)heptanediamide tribromide (1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light-scattering, and zeta potential measurements. As a complement to this, the formation of layer-by-layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20-(phenoxyacetic acid)-porphyrin (2) and 5,10,15,20-(4-(2-ethoxycarbonyl)-4-(2-phenoxyacetamido)heptanedioic acid)-porphyrin (3), is documented. To this end, the layer-by-layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several "on-off" cycles of illumination, we derive monochromatic incident photo-to-current conversion efficiencies of around 3 %.
在当前工作中，我们展示了通过N1,N7-双(3-(4-叔丁基-吡啶甲基)苯基)-4-(3-(3-(4-叔丁基-吡啶甲基)苯基氨基)-3-氧代丙基)-4-(3,4-二羟基苯甲酰胺基)庚二酰胺三溴化物(1)成功实现P-25二氧化钛纳米颗粒的功能化和稳定化。后者的设计旨在利用有机结构单元对纳米颗粒进行功能化和稳定化。一方面，1具有儿茶酚锚定基团，使其能够共价接枝到TiO₂表面，另一方面，其外围带有带正电荷的吡啶基团，通过静电排斥防止TiO₂团聚。热重分析、动态光散射和zeta电位测量证实了功能化和稳定化的成功。作为补充，记录了通过功能化TiO₂纳米颗粒与两种带负电荷的卟啉衍生物即5,10,15,20-(苯氧基乙酸)-卟啉(2)和5,10,15,20-(4-(2-乙氧基羰基)-4-(2-苯氧基乙酰氨基)庚二酸)-卟啉(3)的交替沉积形成受静电相互作用控制的逐层组装体。为此，通过紫外/可见光谱、扫描电子显微镜、椭偏仪和轮廓仪技术监测逐层沉积过程。所得组装体用于构建和测试新型太阳能电池。从在几次光照“开-关”循环中产生的稳定且可重复的光电流，我们得出单色入射光电流转换效率约为3%。
