The Performance Study Of Organic Solar Cells Based On Solvent Strategy

Polymer solar cells(PSCs),as one of a new energy conversion technology,have attracted extensive attention due to its low cost in solvent-processing and potention in flexibility.Over the past decades,the power conversion efficiency of PSCs boosts up to 18% thanks to the emergency of new donor and acceptor.In order to realize high throughput roll-to-roll manufacturing,decrease production cost and improve the reproducibility,the processing procedure of PSCs needs to be simplified and easy fabracaion process can effectively achieve high performance.Though numerous desirable PSCs system has been reported,many of those cells need additive,thermal annealing and other complicated post-treatment,which may improve cost and reduce reproducibility.An as-cast active layer without a solvent additive and any post-treatments can be simply fabricated,which is attractive for the future commercial application.Solvent,as a prerequisite in solvent-processing PSCs,has considerable effect on cells’ performance.In this paper,we are gonging to discuss the solvents stretagy in as-cast PSCs.Non-halogenated solvents mesitylene(MES)was applied to process PBODT: IT-4F blend film as-cast PSC,achieving a PCE up to 9% in the film thickness of 110 nm,which was slightly higher than that of CB fabricated cell.When the thickness of blends increased to 200 and 290 nm,MES-fabricated as-cast device can achieve a similar PCE,a 15% improvement compared to CB-fabracated device in the thickness of 200 and 290 nm.The different performance in thick film between MES and CB-processed PSC indicated that PBODT: IT-4F blend film processed by MES had better processing window in the thickness of 200-290 nm.The film morphology of roughness and domain size could be changed by varying the processing solvent,leading to different performance.This solvent strategy simultaneously linked non-halogen solvent,thick film and as-cast device,which hsd contructive sense to the commercial application in the future.Mixed solvents CF: MES were used to process PTQ10: IT-4Cl film,with a PCE over 13% in the as-cast device.CF was a good solvent of PTQ10 and IT-4Cl and MES could dissolve PTQ10 well.MES acted as a semi-orthogonal co-solvent in CF: MES mixed solvents,due to weak solubility to the acceptor.Blend film could achieve vertical phase separation and cffectively control the film morphology because big boiling point difference between the two kinds solvent could cause formation of the domain of donor and acceptor sequently.Compared to the pure CF fabricated device,the three paramaters Jsc,Voc and FF of PTQ10: IT-4Cl PSC could be simultaneously improved by using a binary solvent system approach in as-cast non-fullerene solar cells.The mixed solvents strategy applied in as-cast device simultaneous improvement of three parameters was rarely seen,which had instructive sense in as-cast PSCs fabricating.