Synthesis And Research On The Properties Of Organic Photovoltaic Materials Based On Side-chain Isoindigo And Phenothiazine

Along with the sharp decrease of fossil fuels and the environmental problems in the course of use, it is urgent for us to seek for clean and renewable energy. At this time, in comparison with the traditional silicon materials, organic photovoltaic(OPV) materials have attracted extensive attention on account of their unique advantages, such as environmentally friendly and low-cost characteristics. And their core competitive superiority lies in the easy processibility, which makes it possible for the low-cost manufacturing technique. In the last dozen years, the unremitting efforts of numerous researchers and development of device architectures have led to the yearly growing power conversion efficieny(PCE), indicating wide potential for the future development. However, the PCE value of OPV materials is still far less than the traditional silicon materials. So we need to try to develop more efficient OPV materials. For that, we have designed and synthesized two types of OPV materials. The structure characterizations of the new synthetic OPV materials have been confirmed by 1H-NMR, 13C-NMR, MALDI-TOF MS and GC-MS, and their photophysical properties, and electrochemical properties, and even the photovoltaic performances have been deeply studied. Primary content of the manuscript is as follows:1. Based on the new synthetic thiophene-benzne-thiophene(TBT) unit, side-chain isoindigo unit, and the introduced thiophene bridge, two novel side-chain conjugated polymers(PTBT-TID and PTBT-TTID) have been designed and synthesized, and applied in the polymer solar cells(PSCs). The polymers, PTBT-TID and PTBT-TTID, possessed relatively good solubility as well as excellent thermal stability, and the PSC devices based on the two polymers got high open circuit voltage(Voc) of about 0.8 V. The device based on the polymer PTBT-TID showed a relatively higher efficiency of 2.0% than the device based on PTBT-TTID.2. Three novel dyes DX1, DX2 and DX3 containing phenothiazine unit have been designed and synthesized, and applied in the dye-sensitized solar cells(DSSCs). The results showed that the DX1-based DSSC device with 0.5 mM chenodeoxycholic acid(CDCA) obtained the highest PCE of 5.69%. When an additional electron-deficient benzothiadiazole(BT) unit was introduced into the molecular structures of the dyes DX2 and DX3, the absorption spectra were broadened. But the short-circuit photocurrent density(Jsc) of the DSSC devices were decreased due to the blocked electron transfer, so the DSSC device based on DX2 only obtained the PCE of 3.43%. Furthermore, a triphenylamine(TPA) unit with high electron-donating ability was joined onto the nitrogen atom of phenothiazine donor in DX3, which enhanced the electron injection efficiency and reduced the dye aggregation. Thus, the Jsc was improved, resulting in a higher PCE of 4.41% in the DX3-based dye than the DX2-based one.