Application Research Of Fluorene Derivative Materials In Inverted Perovskite Solar Cells

Perovskite solar cells have become the research hotspots because of their simple preparation process,high power conversion efficiency,and easy realization of flexibility.However,for commercial application of perovskite solar cells,the efficiency and stability of the devices need to be further improved.As part of cells,hole transport materials play an important role in it.In order to improve the performance of the devices and make a foundation for future commercial applications,this paper focuses on the application and device optimization of new fluorene derivative hole transport materials in perovskite solar cells.The main work is as follows:We introduced two new fluorene derivatives named HDM1 and HDM2 as hole-transporting materials and applied them to inverted planar perovskite solar cells.By means of atomic force microscopy and other characterization testing methods,the properties of the new hole transport materials were studied.We found that the materials HDM1 and HDM2 had good properties in terms of film-forming quality,energy level matching,hole mobility,hole extraction and transport capabilities,which was conducive to improving the efficiency and stability of the device.The optimal preparation process of HDM1 and HDM2 obtained from the experiment was: solution concentration 2 mg/m L,spin coating speed 3000 r/min.Devices using materials HDM1 and HDM2 as hole transport layers achieved efficiency of 17.96% and 18.59%.To optimize the perovskite film,we used(FAPb I3)1-x(MAPb Br3)x mixed cation perovskite system as the light absorption layer.And we fabricated the perovskite layer through the two-step method.The quality of the optimized perovskite film was better,mainly reflected in the larger size of the perovskite grains,the higher crystallinity of the perovskite.The film was uniform and continuous.After device optimization,the device based on material HDM1 had a maximum efficiency of 19.19%,and the device based on material HDM2 had a maximum efficiency of 20.42%.At the same time,the optimized high-performance device had good repeatability,negligible hysteresis effect and good working stability.The application of the new hole-transporting material named WMPA as a hole transport material in inverted planar perovskite solar cells was researched.The best annealing temperature of the material WMPA is 115 ?,and the best thickness of the hole transport layer is 12 nm.The maximum efficiency of the cells using WMPA was 19.33%.Compared with the commonly used hole transport material PEDOT: PSS,the cells efficiency based on the materials PEDOT: PSSW and MPA was 15.22% and 19.33%,respectively.The devices using the material WMPA had a big improvement in short circuit current and open circuit voltage.After photoluminescence spectroscopy testing,it was found that the WMPA material has more excellent hole extraction and transmission capabilities.There fore,it has better performance.The cells based on the material WMPA had good repeatability,negligible hysteresis effect and good working stability.The efficiency of the cells based on the material WMPA remained above 80% of its initial efficiency after 1000 h in the air.While the cells based on the material PEDOT: PSS only retained 60% of the initial efficiency.