Synthesis And Photovoltaic Properties Of Based On PPV Derivatives With Benzothiadiazole And Triphenylamine Side Groups And Organic Dyes With Triphenylamine

This thesis conducted a systematic review over the latest progress in materials and devices of organic solar cells. In the present work, we developed a novel type of poly(p-phenylenevinylene) (PPV) derivatives containing benzothiadiazole groups as low band gap units in the main chains and triphenylamine moieties as side groups. Moreover, a series of donor-π-acceptor (D-π-A) metal-free organic dyes were along synthesized. The structures of these compounds were confirmed by FT-IR, MALDI-TOF,'H NMR, and 13C NMR. The photophysical, electrochemical and potovoltaic properties of the copolymers and dyes were extensively studied by photoluminescence spectra, UV-vis absorption spectra and cyclic voltammogram. We also investigated the PCE of the solar cells based on as-synthesized copolymers and metal-free organic dyes. The main study results are listed below:1 Design and synthesis of a terpolymer (P2) with benzothiadiazole unit as low band gap and triphenylamine moiety as side group. The effects of the low band gap unit on the optical absorption, electrochemical, thermal stabilities and photovoltaic properties of the copolymers were investigated thorough. The benzothiadiazole groups were shown to reduce the band gap of the copolymers, and broaden the absorption band due to their strong conjugation effects. The PCEs of the P2-based bulk heteroj unction polymer photovoltaic cells reached 0.83% under the illumination of AM 1.5 (90 mW cm-2),3 times higher than that of the P1 based counterparts (0.27%) which lack low band gap units.2. In addition, design and synthesis three donor-π-acceptor organic dyes (H1, H2 and H3), These dyes consisted of electron-donating moieties, i.e. di(p-tolyl)phenyla-mine, methylthiophene or alkoxythiophene respectively as electron spacers, and the electron-withdrawing parts, i.e. cyanoacrylic acid groups. Their photophysical, electrochemical and photovoltaic properties were investigated systematically. All these dyes displayed high PCE values. The DSSC based on H1 with methylthiophene asπ-conjugation unit exhibited the maximum PCE of 9.10%(Voc=0.72 V, Jsc=18.03 mA cm-2, FF=0.70) under simulated AM 1.5 G solar irradiation (100 mW cm-2). The result suggests that H1 is a promising candidate for DSSC due to its high efficiency and low cost.