Synthesis And Properties Of Phenothiazine And Triphenylamine-based Solar Cells Materials

Energy is one of the most important factors to influence human life in the 21 st century. The great increasing consumption of fossil fuels, causing global warming and environmental pollution, has led to a greater focus on renewable energy sources and sustainable development. In the past decade, impressive progress has been made in solar energy, both in experimental research and market activity. Donor-acceptor(D-A)conjugated polymers have become the most successful class of polymer donor materials. Recently, series of conjugated polymers were reported for the production of low band gap conjugated polymers for efficient PVCs. This work describes the design and synthesis of a series of new D-A type conjugated polymers and small molecule materials. The resulting materials were characterized by NMR, gel permeation chromatography and thermogravimetric analysis. In additional, the optical and electrochemical properties of these materials were investigated.A series of new random D-A type conjugated polymers based on the phenothiazine and benzo[1,2-b:4,5-b′]dithiophene unit in conjugation with benzooxadiazole and benzothiadiazole unit were designed and synthesized. P1, P2,P3, P4 and P5 were synthesized by different ratio of benzooxadiazole and phenothiazine(respectively 5:1, 3:1, 1:1, 1:3, 1:5) with the benzo[1,2-b:4,5-b′]dithiophene unit. P6, P7, P8, P9 and P10 were synthesized by different ratio of benzothiadiazole and phenothiazine(respectively 5:1, 3:1, 1:1, 1:3,1:5) with the benzo[1,2-b:4,5-b′]dithiophene unit. Thermogravimetric analysis show that these polymers have good thermal stability. The resulting random copolymers are broad absorption bands characterized by UV-vis. The cyclic voltammograms show that these polymers are relatively low energy band gap, which are similar to optical band gap. The band gap and absorption spectra were adjusted by controlling the ratio between the two different units.Three new D-A structure small organic molecular donor materials were designed and synthesized, with phenothiazine as the electron donor unit, 2-ethyl hexyl cyano acetate, malononitrile and 3-ethyl rhodanine as the electron accept unit. The UV-Vis absorption spectrum, cyclic voltammograms, fluorescence spectroscopy and thermogravimetric analysis show that the materials have wide absorption spectra, lowredox potential and good thermal stability.Five copolymers based on benzothiadiazole in combination with dithienosilole,dithienopyrrole, cyclopentadithiophene, fluorene and benzodithiophene were designed and synthesized. The UV-Vis absorption spectra, cyclic voltammograms, fluorescence spectroscopy and thermogravimetric analysis show that these polymers have high thermal decomposition temperature, wide absorption spectra which cover the entire visible light region.