Influence Of Different Substituents On The Photoelectric Efficiency Of Polythiothene

The using of solar power is one of the most important ways to solve the energy crisis and environmental pollution. Due to its unique physical properties and low cost, organic polymer photovoltaic material has received widespread attention and has been a hot area of research in recent years. It has a broad prospect of application in photovoltaic materials, color materials and biological detective aspects.Three different Schiff base monomers were synthesized using glacial acetic acid as catalyst and ethanol as solvent in this research. The structure of the three different substituent of Sciff-base polythiophene was characterized by FT-IR and1H-NMR.In order to investigate the effect of the side chains on the properties of polymer, Poly (3-thiophenecarboxaldehyde condense4-sodium sulfanilate), Poly (3-thiophenecarboxaldehyde condense4-aminobenzoic acid) and poly (3-thiophenecarboxaldehyde condense4-aminophenol) were producted based on3-thiophenecarboxaldehyde condense4-sodium sulfanilate,3-thiophenecarboxaldehyde condense4-aminobenzoic acid and3-thiophenecarboxaldehyde condense4-aminophenol respectively by chemical oxidative polymerization. The structure, molecular weight and its distribution, and thermal stability of the three polymers were measured by FT-IR, gel permeation chromatograph (GPC), and differential scanning calorimetry (DSC), respectively. The results show that the three polymers have better thermal stability, so it can be used as photovoltaic materials.In order to study the optical and electronic performance of the above three kinds of polymers, the light of physical performance, electrochemical performance and photovoltaic performance of the three polymers were tested. The results show that the electrochemical energy gap of Poly (3-thiophenecarboxaldehyde condense4-sodium sulfanilate), Poly (3-thiophenecarboxaldehyde condense4-aminobenzoic acid) and poly (3-thiophenecarboxaldehyde condense4-aminophenol) is3.03eV,2.06eV and2.48eV.The polymer redox curves have good reversibility after introducing three different rigid conjugate substituents, which shows that the polymers have good stability. Photovoltaic performance test shows that the conductivity of Poly (3-thiophenecarboxaldehyde condense4-sodium sulfanilate), Poly (3-thiophenecarboxaldehyde condense4-aminobenzoic acid) and poly (3-thiophenecarboxaldehyde condense4-aminophenol) is4.38×10-6S·m-1,3.98×10-6S·m-1and5.88×10-7S·m-1. This is because hydroxy mainly shows conjugation effect and is a electron-donating group when connected to conjugate system, which makes the electron mainly concentrate in the conjugate main chain. As carboxyl is a electron-withdrawing group, it reduces the conductivity of the device under the illumination.