Synthesis Of D-A-π-A Sensitized Dyes Based On Acceptor Modification And The Investigation Of Their Properties

For pure organic dyes,the molecular structure,especially for the molecular planarity,can effectively regulate multiple molecular properties.In this thesis,a series of organic dyes were designed and synthesized by using cyclization strategies to improve the planarity of the acceptor part of D-A-π-A dyes.The effects of moleuclar planarity on the properties were systematically studied.The first chapter introduces the research background and development of organic dyes applied in DSSCs.The recent research progress of organic dyes were summerized.Based on this,the research ideas and research content of this thesis are proposed.In chapter 2,two dyes CS-85 and CS-87 were synthesized by improving the molecular planarity of the acceptor part.Along with the improvement of molecular planarity,the molar extinction coefficient of the dyes were also effectively enhanced,which would increase the light-harvesting capability,leading to the larger photocurrent.The positional isomerization of carboxyl group has little impact on charge injection efficiency.However,the dye regeneration efficiency and charge collection efficiency of CS-85,which owns 4-carboxyl group,was higher than that of CS-87,which owns 3-carboxyl group.Under the same conditions,dye CS-85 achieved relatively high photocurrent,photovoltage,and power conversion efficiency due to its large molar extinction coefficient.In chapter 3,based on the reference indoline dye CS-31,the dyes CS-92 and CS-93 were synthesized by improving the planarity of acceptor part.Among them,CS-92 presented the highest molar extinction coefficient,which would increase its light-harvesting capability,being conducive to obtaining higher photocurrent.The improvement of planarity at acceptor part has not obvious effect on interfacial charge transfer efficiencies,including charge injection efficiency and dye regeneration efficiency,but significantly improved the charge collection efficiency of CS-92.Due to the highest light-harvesting capability and charge collection efficiency,DSSCs based on CS-92 achieved the highest photocurrent,photovoltage,and power conversion efficiency.In chapter 4,Conclusion.