The Design,Synthesis And Photovoltaic Properties Of New Conjugated Polymers Based On Red Hair Pigment Skeleton

In recent years,polymer solar cells?PSCs?have gained more and more attention due to their light weight,flexible and solution processibility.It is one of the main advantages of polymer solar cells and one of the main development directions of polymer solar cells that they can be easily modified by synthesizing new monomer and modificating the polymer's structure.Nowadays,conjugated polymers based on natural pigment structure have become more and more popular because of their wide source and low price.Among them,the isoindigo dyes have attracted much attention in the field of polymer solar cells due to their unique chemical structure and excellent properties.Red hair pigment is a kind of natural pigment existing in human red hair.It has a similar structure to indigoid and has never been applied in the field of organic photovolatic.In this paper,two novel monomers based on the skeleton of the red hair pigment C were designed and synthesized.Their main structure is benzothiazine-indigo.In the second chapter of this paper,we synthesized a novel monomer?2E?-7-bromo-2-?7-bromo-3,4-dihydro-3-oxo-2H-1,4-benzothiazin-2-ylide ne?-2H-1,4-benzothiazine-3?4H?-one and it has been co-polymerized with electron rich benzodithiophene?BDT?and electron deficient diketopyrrolopyrrole?DPP?to give two conjugated polymers.Then the optical and electrochemical properties of these two polymers were characterized.In the chapter three,we synthesized a novel monomer?2E?-6-bromo-2-?6-bromo-3,4-dihydro-3-oxo-2H-1,4-benzothiazin-2-ylide ne?-2H-1,4-benzothiazine-3?4H?-one and also co-polymerized it with BDT and DPP.The polymer BTI2-DPPT was used as the donor material and PC₇₁BM was used as the acceptor material to prepare the corresponding polymer solar cell devices.The power conversion efficiency of the solar cell was 2.27%.This study introduced a new indigoid building block for conjugated polymers.