Synthesis And Study On The Properties Of Organic Photovoltaic Materials Containing Triphylamine, Thiophene And Benzothiadiazole

Solar energy is the largest carbon-neutral energy source that has not been fully utilized. Although there are solar cell devices based on inorganic semiconductor to efficiently harvest solar energy, the cost of these conventional devices is too high to be economically viable. This is the major motivation for the development of organic photovoltaic (OPV) materials and devices, which are envisioned to exhibit advantages such as low cost, flexibility, and abundant availability. Polymer soalr cells (PSCs) and dye-sensitized solar cells (DSSCs) have attracted considerable attention. The absorption spectra, hole-injecting/transporting property and solubility of photovoltaic materials have obvious influences on the power conversion efficiency (PCE) of PSCs and DSSCs. The main results are as follows:1. Three novel low band gap copolymers (P1, P2 and P3) containing dihexylthienylbenzothiadiazole (DTBT) with/without triphenylamine (TPA) and tetraphenylbenzidine (TPD) have been designed and synthesized. The study results showed that with the introduction of TPA and TPD, the absorption spectra of P2 and P3 were broadened and red-shifted. Besides, the charge carrier mobility and photovoltaic performance of the copolymers were enhanced. Under AM 1.5 100 mW/cm2, the maximum PCE of P1, P2 and P3 are 0.97%,0.49%,1.11% respectively.2. A novel triphenylamine dye (FD1) modified with alkyl-thiophene and double bonds was designed and synthesized for DSSCs. We systematically studied the effects of double bonds in theπ-spacer on the photophysical, electrochemical properties and power conversion efficiency (PCE). The study results showed that with the introduction of double bonds the absorption spectra of FD1 were broadened and red-shifted. Besides, the molar extinction coefficient were improved. After optimizing the solvent and TiO2 film thickness, FD1 showed the best photovoltaic performance:a short-circuit photocurrent density (Jsc) of 12.57 mA/cm2, an open-circuit photovoltage (Voc) of 0.76 V, and a fill factor (FF) of 0.74, corresponding to a PCE of 7.04% under AM 1.5 G 100 mW/cm2 solar irradiation...