| Due to the environmental pollution caused by traditional fossil energy,solar energy as a clean energy has been widely concerned.Perovskite solar cells(PSCs),as a new type of solar cells,has been widely concerned in recent years due to its advantages such as high efficiency,simple manufacturing process and rapid development.As an important part of battery components,hole transport material(HTM)has become an important research in this field.In traditional forward batteries,commercial spiro-OMe TAD has been widely used.However,the low hole mobility of the material requires doping lithium salt and tert-butyl pyridine to improve the photoelectric conversion efficiency of the battery,which leads to the decrease of the stability of the battery.Therefore,it is of great significance to develop non-doped cavity transport material for the preparation of efficient and stable perovskite solar cell devices.In this paper,with dithieno[3,2-b:2?,3?-d]pyrrole(DTP)as the conjunct unit and by adjusting the power supply unit and the central nuclear,four new kinds of doped cavity transport materials(M6,M6-F,M6-F-O and M7)were designed and synthesized.The optical physics electrochemical properties,thermal stability and membrane morphology of these HTMs were studied in detail.Perovskite solar cells were prepared to study the photovoltaic properties of these HTMs under the condition of doped-free.It was found that the combination of methoxy-substituted triphenylamine(OMe-TPA)and DTP as side chain OMe-TPA-DTP was more effective than the combination of methoxy-substituted triphenylamine and thiophene.In addition,the central screw check plays an important role in improving the film-forming performance of HTMs,and the introduction of fluorine atoms into screw[fluoren-9,9'-oxacene](SFX)can improve the intermolecular interaction.Through hole mobility test,it is found that M6,M6-F,M6-F-O and M7 have much higher intrinsic mobility than spiro-OMe TAD,which indicates that these HTMs have the potential to be non-doped hole transport materials.Among all HTMs,M6-F based on OMe-TPA-DTP side chains and fluorine-substituted SFX has good hole transport performance and film-forming properties.Applied to the structure of ITO/Sn O2/KCl/Perovskite/HTM/Au perovskite solar cells,and based on the M6-F device shows the best performance,the photoelectric conversion efficiency(PCE)is18.25%,the open circuit voltage(Voc)is 1.14V,short circuit current density(Jsc)is22.33 m A cm-2,fill factor(FF)is 0.72.Steady state photoluminescence(SSPL)was used to determine the quenching efficiency of HTMs to represent the efficiency of extraction of holes from perovskite by HTMs.The fluorescence quenching time data obtained by time-resolved transient photoluminescence(TRPL)test indicated that M6-F could separate the holes from perovskite the fastest and transport them quickly.M6-F based devices retain 98%of their initial efficiency after 960 hours of unpackaged storage(humidity 30%,ambient.air environment).The research results of this paper provide important theoretical and experimental basis for the design and synthesis of organic doped-free HTMs,and have positive significance for improving the practicability of perovskite solar cells. |
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