Effect Of Active Layer Treatment On Properties Of Ternary Blended Organic Solar Cells Based On ?tbt?₂Ir?acac?

Among the various methods of improving the performance of organic solar cells,the ternary system is easy to implement.It has attracted more and more attention by scientific research teams.In this paper,the Iridium complex small molecule material?tbt?₂Ir?acac?was incorporated as the third component in conventional active layer of P3HT and PC₇₁BM.The active layer was treated by combining two annealing processes.The effects of doping materials and two-step annealing process on device were investigated.Firstly,the effects of different doping ratios of Iridium complex small molecular material?tbt?₂Ir?acac?on device were investigated.It can be found that when the doping ratio of?tbt?₂Ir?acac?reaches 3.0 wt%,the three components P3HT:?tbt?₂Ir?acac?:PC₇₁BM have the best performance.The device voltage V_OC is 0.54 V.The short-circuit current J_SC of the device is 11.30 mA/cm².The fill factor FF of the device is 60.38%,and the energy conversion efficiency of the device PCE is 3.64%,with a 20%increase.The performance improvement of the device is mainly due to the doping of?tbt?₂Ir?acac?,which forms a good energy level gradient arrangement between P3HT,?tbt?₂Ir?acac?and PC₇₁BM in the active layer of the device,which is beneficial to the loading and the transmission of carrier.At the same time,due to the F?rster energy transfer effect between the material?tbt?₂Ir?acac?and P3HT,the utilization of photons by the device is improved.In addition,the doping of?tbt?₂Ir?acac?also improves the morphology of the active layer of the device,so the fill factor FF and the short-circuit current J_SC of the device are improved.Subsequently,in order to further improve the performance of the three components,the active layer was annealed using different solvents,and the influence of different solvents on the active layer of the device was preliminary researched.Then,we use the two-step annealing process to treat the active layer with different solvents.The characteristics of the device were characterized.When we use methanol as solvent to treat the active layer of the device we can get the best performance.t.At this time,the open circuit voltage V_OC of the device is 0.53 V.The short circuit current J_SC of the device is12.51 mA/cm²,and the fill factor FF of the device is 61.81%.The efficiency PCE is4.07%.The energy conversion efficiency of the device is improved by 39.8%compared to the device without any active layer treatment.The two-step annealing method can effectively control the morphology of the active layer of the device,so that the roughness of the surface of the P3HT:?tbt?₂Ir?acac?:PC₇₁BM ternary system device increases correspondingly.The relatively rough surface morphology facilitates efficient separation of excitons and transport and collection of carriers.In summary,Iridium complex small molecule material?tbt?₂Ir?acac?was used to dope the binary system of P3HT:PC₇₁BM,and a novel two-step annealing method was used on the devices.This paper provides a new idea and method for the development of new ternary organic solar cells with high performance.