光致电子转移(ET)是有机光电器件中载流子光生最重要的过程。在基于偶氮化合物的层状光感受器中,载流子光生通过空穴传输材料 (HTM) 的掺入而敏感。我们研究了这个过程以阐明高度敏化的机制。首先,测量并比较层状光感受器和载流子生成层的光致 ET 效率和整体量子效率。HTM 增强光诱导 ET 的结果意味着 HTM 催化作用以减少活化能。尽管这种外在 ET 独立于电场发生,但随后的成对解离取决于电场。下一个,通过使用 50 多个光感受器在很宽的范围内改变能隙,研究了 ET 的能隙依赖性。测量的效率针对能隙绘制,其中未观察到倒置区域。
光致电子转移(ET)是有机光电器件中载流子光生最重要的过程。在基于偶氮化合物的层状光感受器中,载流子光生通过空穴传输材料 (HTM) 的掺入而敏感。我们研究了这个过程以阐明高度敏化的机制。首先,测量并比较层状光感受器和载流子生成层的光致 ET 效率和整体量子效率。HTM 增强光诱导 ET 的结果意味着 HTM 催化作用以减少活化能。尽管这种外在 ET 独立于电场发生,但随后的成对解离取决于电场。下一个,通过使用 50 多个光感受器在很宽的范围内改变能隙,研究了 ET 的能隙依赖性。测量的效率针对能隙绘制,其中未观察到倒置区域。
A Rational Design of Electrochemically and Photophysically Tunable Triarylamine Luminophores by Consecutive (Pseudo‐)Four‐Component Syntheses
作者:Regina Kohlbecher、Thomas J. J. Müller
DOI:10.1002/chem.202304119
日期:2024.3.20
The concatenation of Suzuki coupling and two‐fold Buchwald‐Hartwig amination in sequentially palladium‐catalyzed consecutive multicomponent syntheses paves a concise, convergent route to diversely functionalized para‐biaryl‐substituted triarylamines (p‐bTAAs) from simple, readily available starting materials. An extensive library of p‐bTAAs permits comprehensive investigations of their electronic properties by absorption and emission spectroscopy, cyclic voltammetry, and quantum chemical calculations, which contribute to a deep understanding of their electronic structure. The synthesized p‐bTAAs exhibit tunable fluorescence from blue to yellow upon photonic excitation with quantum yields up to 98 % in solution and 92 % in the solid state. Furthermore, a pronounced bathochromic shift of the emission maxima by increasing solvent polarity indicates positive emission solvatochromism. Aggregation‐induced enhanced emission (AIEE) in dimethyl sulfoxide (DMSO)/water mixtures causes the formation of intensely blue fluorescent aggregates. Cyclic voltammetry shows reversible first and second oxidations of p‐bTAAs at low potentials, which are tunable by variation of the introduced para substituents. 3D Hammett plots resulting from the correlation of oxidation potentials and emission maxima with electronic substituent parameters emphasize the rational design of tailored p‐bTAAs with predictable electrochemical and photophysical properties.