The Study Of Multi Component And Wide Spectrum Organic Solar Cells

Organic solar cells have the advantages of green and pollution-free,low cost,light quality,flexible and large area preparation.It has become a key scientific research field for modern scientists to develop new energy and applications.At present,the organic solar cells with non fullerene small molecules acceptor materials become the main stream,and its photoelectric conversion efficiency has exceeded 14%.However,for the conventional heterojunction solar cell system,the photoelectric conversion efficiency has been limited because of its limited optical absorption range and weak photon capture ability.In order to overcome the defects of two component blends of organic solar cells,a solar cell system with three element blends was designed in this work.On the basis of an original electron donor and an electron acceptor,the blend solar cell was prepared by adding third components.The third component often has the function of widening absorption,better charge transfer performance and forming gradient energy level,thus improving the performance of solar cells.Based on this,this paper takes widening the optical gap as the breakthrough point,and improves the photoelectric conversion efficiency of solar cells through the three component blending strategy.By studying the optical,spectroscopic,morphological and electrical characteristics of active layer and device,the working principle of the device is explained.The main research results and innovation points in this paper are as follows:1.New organic polymer photovoltaic materials(PBDTNS-TPD and PBDTNS-TPD)based on thieno[3,4-c]pyrrole-4,6-dione(TPD)acceptor unit were designed and synthesized.Compared with the performance difference between the two polymer,the study found that:the polymer with alkylthio-naphthyl-substituted benzo[1,2-b:4,5-b']dithiophene(BDT)units shows a lower HOMO energy level and a higher open circuit voltage(Voc),which has a great contribution to the performance of organic solar cells.Using PBDTNS-TPD as the third component in photovoltaic devices,a PCE of 9.48%with a Voc of 0.93 V,an Jsc of 16.07 mA/cm2 and an FF of 63.44%was obtained.2.New organic polymer material(PBDTNS-BDD and PBDTNO-BDD)was synthesized with 1,3-bis(5-bromothiophen-2-yl)-5,7-bis(2-ethylhexyl)4H,8H-benzo-[1,2-:4,5-c']dithiophene-4,8-dione(BDD)unit as an electron-withdrawing unit and an electron-donating benzo[1,2-b:4,5-b']dithiophene(BDT)building block containing alkylthio naphthyl unit or alkyloxyl naphthyl unit as side chain.The study found that:The polymer with alkylthio naphthyl side chain has excellent performance in all aspects compared to alkyloxyl naphthyl side chain.We fabricated multi component organic solar cell devices with different proportions.With the addition of third component ITIC,short circuit current(Jsc)increased significantly.Short circuit current(Jsc)increased from 15.36 mA/cm2 to 17.77 mA/cm2,and photoelectric conversion efficiency increased from 7.85%to 11.21%.