High Ionization Potential Conjugated Polymers

We report the synthesis of a series of poly(p-phenylene ethynylene)s (PPEs) with high ionization
potentials and associated high excited-state electron affinities. Their photophysical properties were
investigated using steady-state and time-resolved fluorescence techniques. The ionization potentials of
the polymer thin films were determined using ultraviolet photoelectron spectroscopy (UPS), and those with
the highest ionization potentials displayed high sensitivity for the detection of electron-donating aromatic
compounds. The effects of sterics, chemical structure, and electronic properties on the polymers' sensory
responses were investigated by fluorescence quenching experiments in both solution and solid thin films.
In addition, we report that in some cases the excited-state charge-transfer complexes (exciplexes) of the
PPEs with analytes were observed. These latter effects provide promising opportunities for the formation
of sensitive and selective chemical sensors.

本研究报道了一系列兼具高电离电势与对应高激发态电子亲和能的聚对苯撑乙炔（poly(p-phenylene ethynylene)s，PPEs）的合成工作。研究采用稳态及时间分辨荧光技术对该类聚合物的光物理性质进行了表征；通过紫外光电子能谱（ultraviolet photoelectron spectroscopy，UPS）测定了聚合物薄膜的电离电势，结果表明，拥有最高电离电势的PPEs对给电子型芳香族化合物具备极高的检测灵敏度。本研究还通过溶液与固态薄膜中的荧光淬灭实验，系统探究了空间位阻效应、化学结构及电子性质对聚合物传感响应的影响。此外，研究发现在部分体系中可观测到PPEs与分析物形成的激发态电荷转移复合物（exciplexes，激基复合物）。上述这类效应为制备高灵敏度、高选择性的化学传感器提供了广阔的应用前景。