Molecular Engineering And Performance Studies Of Rhodanine Dyes Based On D-?-A Construction

With the breakthrough improvement of the photoelectric conversion efficiency of dye-se nsitized solar cells?DSSCs?,the sensitizers,especially organic sensitizers,have attracted mor-e and more attentions due to their rare metal-free structures,ease of synthesis and purification in the past two decades.And they have been extensively explored because of their tunableproperties.In this paper,four new rhodanine dyes were designed and synthesized.The dye sensitizers were used to prepare dye-sensitized solar cells and their properties were studied.In chapter 1,we briefly describe the classification and characteristics of the sensitizers,review the research progress of the sensitizers with cyanoacetic acid and rhodanine acceptors in recent years,and introduce the purpose and research content of the paper.In chapter 2,we use carbazolyl porphyrin groups as the electron donors,phenyl or thiophene groups as the?bridges,and cyanoacetic acid,rhodanine-3-acetic acid and the modified rhodanine as the electron receptors,a series of new sensitizers,CS-23,CS-24,CS-25 and CS-26 are designed and synthesized.The structures of all the compounds are confirmed by NMR spectroscopy and LC-MS.In chapter 3,the photophysical and electrochemical properties of four novel dye sensitizers were studied,and the Gaussian 09 program was used to quantify the properties of the ground state and first excited state of the four dyes.In addition,four kinds of dyes were used to make the devices and the photovoltaic performance of the series of dyes was studied detail.We found that using conjugated cyanoacetic acid instead of the unconjugated carboxyl group would enhance the light trapping ability of the dye and the electron injection process would be smoother.Meanwhile,long alkyl chain was also introduced into rhodanine segment to prevent?-aggregation on TiO₂ surface and restrain the charge recombination,leading to an obvious improvement of the photovoltage.Accordingly,without any co-adsorbent,the dye CS-22 presented the record PCE of 8.48%among all four dyes,with a J_SCC of 17.49 mA cm^-2,a V_OC of 713 mV,and a fillfactor of 0.681,while only around 5%decline in PCE was found after 1000 h aging test.It can be seen from this that the dye also has high stability.In chapter 4,the conclusions were presented.