Synthesis and Optoelectronic Properties of Porphyrin-Modified D-A Type Conjugated Polymers

With the advent of the intelligent era, the explosive growth of the amount of information has led to a strong demand for the development of storage devices with larger capacity, greater stability and more comprehensive functions. Among many alternative materials, organic polymers can be designed with different structures to regulate the electrical properties, thus attracting the attention of researchers. We polymerized p-phenylene diacetonitrile and zinc porphyrin by Knoevenagel condensation reaction to obtain the D-A type conjugated polymer PCN-ZnPor, and then tested the material, which has good thermal stability and is soluble in polar solvents. The Al/PCN-ZnPor/ITO devices prepared with the polymer as the active layer film showed non-volatile erasable resistive variable storage performance with a turn-on voltage of −3.04 V, and the current switching ratio of 7×10³. After durability test, the ON state and OFF state of the Al/PCN-ZnPor/ITO device correspond to the current basically remain at a relatively stable value, which indicates that the device has good stability and reproducibility. Meanwhile, we performed in situ fluorescence tests on PCN-ZnPor films spin-coated on ITO substrates. When a voltage greater than the ON voltage (−3.04 V) was applied, no change in the shape of the fluorescence spectra was observed, while the overall fluorescence intensity was weakened. This fluorescence quenching behavior may be related to the charge transfer between the metal zinc porphyrin and the main chain of the polymer with a cyano group, which is consistent with the transition of the device from the OFF state to the ON state, suggesting that intramolecular charge transfer may have taken place in our prepared devices. This work demonstrates the great potential of porphyrin-containing polymers in the field of high-density storage.