Study On Synthesis And Properties Of Photosensitive Dyes Modified By Planarized Triphenylamine

Dye-sensitized solar cells(DSSC)have always been a hot spot in the research of organic solar cells,and the design of new donor building blocks and dye molecules is an idea to improve cell efficiency and stability.In order to develop a new planarized donor building block,a planarized triphenylamine donor CM and introduced methoxy modification CMo were synthesized using Ullmann reaction,nucleophilic addition and other reactions to improve its electron donating ability.The common triphenylamine donor MTPA and indoline donor YD were used as references to study the absorption spectrum and molecular orbital energy level of the planarized donor CMo.The results show that CMo has broadened the absorption spectrum and it has better electron donating ability.its LUMO energy level is higher,and it has a greater driving force for electron transfer,which shows that CMo is a new kind of donor applicability of body blocks.Using CM and CMo as electron donors,benzotriazole as the first acceptor,pyrimidine ring as the second acceptor,and cyanoacetic acid as the anchor group,two charges separated(CS type)dyes CMBT-Pyc and CMoBT-Pyc are synthesized by Heck reaction and Wittig reaction,and the triphenylamine donor dye MTPABT-Pyc without planarization as a reference.According to testing the steady-state spectra,transient spectra,energy levels of the dyes,the results show that the absorption spectra of the dyes CMBT-Pyc and CMoBT-Pyc have been broadened,but the corresponding energy level difference is reduced,and the electron transfer rate is reduced.The target dyes CMBT-Pyc and CMoBT-Pyc are used as DSSC photosensitizers to prepare DSSC devices,analyzing the photovoltaic performance of the devices and the results in combination with the photophysical process compared with MTPABTPyc.Although the absorption spectrum is somewhat different Broadened,the PCE decreased.Because the modification of the methoxy group enhanced the electron donating ability of the donor,but weakened the intermolecular interaction of the dye on the film and reduced the amount of dye adsorbed on the photoanode so that its PCE has been reduced.This article provides guidance for the design of new sensitizing dyes.