Preparation And Performance Of Ternary Organic Solar Cells Based On PM6:Y6:IT-M

There are many ways to improve the performance of organic solar cells,and ternary system is one of the effective and easy to achieve ways.In recent years,more and more research teams have devoted themselves to the frontier research of ternary organic solar cells.In this paper,the non fullerene material it-m was added into the high efficiency PM6:Y6 binary organic solar cell as the third component.After determining the appropriate doping concentration,the active layer of the device was treated by two-step annealing method,namely solution annealing and high-temperature annealing,so as to further improve the performance of the device The influence of annealing process on device performance.Firstly,the open circuit voltage(V_OC)and short circuit current(J_SC)of the binary system were improved by energy level cascade and broadening absorption spectrum.The non fullerene material IT-M was doped into the binary system,and the effects of different doping ratios on the parameters of binary organic solar cells were studied.When the doping ratio of IT-M reaches 20 wt%,the three components PM6:IT-M:Y6 have the best performance.At this time,the battery has 0.82V open circuit voltage V_OC,short-circuit current J_SC of 28.83 mA/cm²,fill factor FF of 61.21%,energy conversion efficiency of 14.40%,which is 16%higher than binary standard.The improvement of device performance is mainly due to the higher LUMO and HOMO of IT-M than that of Y6 and PM6.With the increase of open circuit voltage,the LUMO levels of the three materials in the active layer of the device form a good arrangement,which we call the cascade of energy levels,and the carrier transport ability is improved.At the same time,the absorption spectrum is broadened and the short circuit current J_SC is increased.In addition,the doping of it-m makes the morphology of the active layer more conducive to the performance of the device,and the energy conversion efficiency of the device is improved.Subsequently,in order to further improve the performance of ternary organic solar cells,a two-step annealing process was adopted,using different solvents combined with high-temperature annealing to treat the active layer of the device,and characterization experiments were carried out on the related characteristics of the device.The experimental results show that the performance improvement of the device is the biggest in the two-step process using methanol and high-temperature annealing.The open circuit voltage V_OC is 0.82V,the short-circuit current J_SC is 30.19 mA/cm²,the filling factor FF is 63.47%,and the energy conversion efficiency is 15.72%.Compared with the single annealing process,the performance of the device is improved by 8.4%.The two-step annealing method can effectively control the morphology of active layer,which makes the surface morphology of PM6:IT-M:Y6 ternary system device more conducive to the effective separation of excitons and carrier transport and collection.In conclusion,PM-6:Y6 binary system was doped with non fullerene it-m,and the device was treated by two-step annealing process.It can greatly improve the performance of organic solar cells,which has great value for the research of organic solar cells.