聚合物修饰电极是近几年研究的热门领域，其在能量转换与储存、电催化、电化学传感器和生物传感器等领域具有广阔的应用前景。其中噻吩基小分子由于其成本低、合成简单、能级可控的性质及较高的固态电子转移速率使其研究更为广泛。本文主要设计合成了两个三噻吩修饰的小分子单体L¹和L²，并采用电化学方法制备了两种二聚体电沉积薄膜，并研究它们的电化学、光电化学及电催化性质。最后初步研究了两种单体的酸碱和阳离子传感性质。本论文的主要工作及创新点如下：

（1）合成了两个三噻吩基小分子单体L¹和L²，并通过核磁共振氢谱、质谱、元素分析对其进行了表征；通过紫外-可见吸收光谱和荧光发射光谱研究了两个单体在不同溶剂中的发光情况。结果表明两种单体在有机溶剂中均具有较高的量子产率，其中单体L¹在CH₂Cl₂中的荧光量子产率最大，为0.15，单体L²在CH₃OH中的量子产率最大，为0.58。且共轭性更好的L²具有更明显的溶剂变色效应。

（2）基于噻吩基团的可聚合的特点，利用电化学聚合方法，制备了单体L¹二聚体的电沉积薄膜Film(dimer-L¹)_n。利用光电子能谱和扫描电镜，对薄膜的形貌和化学组成进行了研究；利用循环伏安技术、电化学阻抗谱和光电化学测量技术，研究了薄膜的电化学和光电化学性质。结果表明，在-0.4 V（vs. SCE）的偏压下，2层电沉积薄膜Film(dimer-L¹)₂产生的光电流（光电流密度）达到最大值为24.46 μA（87.36 μA cm^-2）；在氧气饱和的电解液中，产生的光电流为30.46 μA，约为氮气饱和的电解液中产生的光电流3.89 μA的7.8倍；在450 nm处的IPCE值为0.90%。此外，薄膜具有电催化氧还原产生H₂O₂的性质。薄膜在施加7 h的-0.2 V（vs. SCE）偏压后，氧饱和的0.1 M Na₂SO₄溶液中最大可产生4.79-5.21 μM cm^-2的H₂O₂；化学转化数最大值约为80；施加偏压半小时内具有最大的法拉第效率，为33.96%。结果表明单体L¹的二聚体薄膜Film(dimer-L¹)_n具有良好的光电化学性质及电催化氧还原性质，其在光电转化，氧传感及电化学制备H₂O₂方面有广阔的应用前景。

（3）与单体L¹的二聚体薄膜类似，单体L²也可通过电化学聚合的方法沉积在ITO表面，形成浅红棕色电沉积薄膜Film(dimer-L²)_n。同样的，单体L²的二聚体薄膜Film(dimer-L²)_n也具有良好的光电性质。在-0.4 V（vs. SCE）的偏压下，10层电沉积薄膜Film(dimer-L²)₁₀产生的光电流（光电流密度）达到最大值9.32 μA（33.29 μA cm^-2）。此外，该薄膜也具有电催化氧还原产生H₂O₂的性质。15层电沉积薄膜Film(dimer-L²)₁₅在施加7 h 的-0.2 V（vs. SCE）偏压的氧饱和的电解质溶液中，最多能产生3.27±0.21 μM cm^-2的过氧化氢；化学转化数最大可达300左右；法拉第效率在半小时时达到最大值，为33.15%。结果表明该薄膜在电化学/光电化学氧还原催化剂和电化学制备H₂O₂的方面有着同样的应用前景。

（4）研究了pH值对两种单体L¹和L²溶液的紫外-可见吸收光谱和荧光发射光谱的影响。结果表明，随着溶液的酸度变化，探针分子L¹和L²均是off-on-off的荧光开关，最大on-off比分别为7.5和19.0，最大发射峰位移分别为23 nm和36 nm。其中单体L¹作为pH荧光探针时，具有良好的重复性、稳定性和可逆性。当缓冲溶液由酸性变为碱性时，可肉眼在紫外灯下（365 nm）观察到单体L¹溶液发光到由黄色变为绿色。此外，单体L¹在含有金属离子Co²⁺、Cu²⁺、Hg²⁺和Ag⁺的碱性缓冲溶液中发生荧光淬灭现象。表明单体L¹在金属离子荧光探针和pH荧光探针领域有潜在的应用前景。

Polymer-modified electrodes have been a research hotspot in recent years due to their broad application prospect in energy conversion and storage, electrocatalysis, electrochemical and biosensors and other fields. Among them, thiophene-based molecules have been studied extensively due to low cost, simple synthesis, controllable energy levels and high solid electron transfer rates. In this dissertation, two terthiophene-modified organic small molecule monomers of L¹ and L² were synthesized, and two electrodeposited films of their dimers were fabricated by electrochemical method. And the electrochemical, photoelectrochemical and electrocatalytic properties of the films were studied. Finally, the acid-base and metal cation sensing properties of L¹ and L² were also preliminarily studied. The main work and innovation of this dissertation, are as follows:

(1) Two terthiophene-based monomers of L¹ and L², were synthesized and characterized by elemental analysis, and ¹H nuclear magnetic resonance and mass spectroscopy. The solvatochromic properties of L¹ and L² were studied by UV-vis absorption and fluorescence emission spectroscopy as well.

(2) Based on the polymerizability of thiophene moiety, the electrodeposited film of dimer-L¹, Film(dimer-L¹)_n, was prepared by electrochemical polymerization. The morphology and chemical composition of the films were studied by scanning electron microscopy and X-ray photoelectron spectroscopy. And the electrochemical and photochemical properties of the films were studied by cyclic voltammetry, electrochemical impedance specroscopy and photoelectrochemical measurements. The results showed that the maximum photocurrent (photocurrent density) of Film(dimer-L¹)₂ was 24.46 μA (87.36 μA cm^-2) at the bias potential of -0.4 V (vs. SCE). The photocurrent generated by the film in the oxygen-saturated electrolyte was 30.46 μA, which was 7.8 times the photocurrent generated for the same electrode in the nitrogen-saturated electrolyte (3.89 μA). The IPCE value of Film(dimer-L¹)₂ at 450 nm was determined to be 0.90%. In addition, the films could produce hydrogen peroxide of 4.79-5.21 μM cm^-2 in an oxygen-saturated 0.1 M Na₂SO₄ aqueous solution biased at -0.2 V (vs. SCE) for 7 h. The maximum Faraday efficiency of the films was 33.96% within half an hour of bias. And the maximum turnover number of Film(dimer-L²)₁₀ reached about 80. The results showed that the electrodeposited film, Film(dimer-L¹)_n, had excellent photoelectrochemical and electrocatalytic properties, holding broad application prospects in photoelectric conversion, oxygen sensing and electrochemical synthesis of hydrogen peroxide.

(3) Similarly to L¹, the monomer L² could also be electro-oxidized into dimer-L², which was finally deposited onto the ITO substrate surface, forming the light reddish brown electrodeposited film, Film(dimer-L²)_n. At the bias potential of -0.4 V (vs. SCE), the photocurrent (photocurrent density) generated by Film(dimer-L²)₁₀ reached a maximum value of 9.32 μA (33.29 μA cm^-2). Similarly to Film(dimer-L¹)_n, Film(dimer-L²)_n also exhibited the properties of electrocatalytic oxygen reduction to produce hydrogen peroxide at a concentration of 3.27±0.21 μM cm^-2 in an oxygen-saturated electrolyte solution biased at -0.2 V (vs. SCE) for 7 h, and the maximum turnover number of Film(dimer-L²)₁₀ reached about 300. The maximum Faraday efficiency of the films was 33.15% within half an hour of bias. These results indicated that Film(dimer-L¹)_n, Film(dimer-L²)_n have application prospect in electrochemical oxygen reduction catalyst to generate hydrogen peroxide and solar photoelectric conversion.

(4) The acid-base properties of two monomers of L¹ and L² were studied by UV-visible absorption and photoluminescence spectrophotometric titration technique. The results showed that the probe molecules L¹ and L² both acted as pH-induced off-on-off fluorescence switches with L¹ being of good repeatability and reversibility. When the solution changed from acidic to alkaline, the luminescence of monomer L¹ solution was observed to change from yellow to green under the UV lamp (365 nm). In addition, metal cations of Co²⁺, Cu²⁺, Hg²⁺ and Ag⁺ were found to quench the emission of L¹ in alkaline aqueous solution, indicating that monomer L¹ could be used as a fluorescent probe for detection of the metal ions.